IO - Revision history

Robertson at 18:18, 5 May 2025

2025-05-05T18:18:20Z

Arango: /* Output Multi-Files */

2023-03-11T20:51:32Z

Output Multi-Files

← Older revision		Revision as of 20:51, 11 March 2023
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	<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>		<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>

	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain '''5'''-time records because of the initial conditions, and the rest of the files will have '''4'''-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain '''9'''-time records, and the rest will have '''8'''-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. If [[Variables#dstart\|DSTART]] is changed, it will reset the timestep internal counter <span class="red">iic(ng)</span>, and we are in deep trouble! Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. If [[Variables#dstart\|DSTART]] is changed, it will reset the timestep internal counter <span class="red">iic(ng)</span>, and we are in deep trouble! Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

Arango: /* Output Multi-Files */

2023-03-11T20:49:59Z

Output Multi-Files

← Older revision		Revision as of 20:49, 11 March 2023
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	* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>		* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>

	* Timestamp assigned for model initialization, reference time origin for tidal forcing, and model reference time for output NetCDF units attribute.<div class="box"> [[Variables#dstart\|DSTART]] = 365.0d0 ! days <span class="mediumOrchid">(ROMS is initialized on 2007-01-01 00:00:00Z)</span><br /> [[Variables#tide_start\|TIDE_START]] = 0.0d0 ! days<br /> [[Variables#time_ref\|TIME_REF]] = 20060101.0d0 ! yyyymmdd.dd <span class="mediumOrchid">(Very important: ROMS time is seconds since 2006-01-01 00:00:00Z)</span></div>		* Timestamp assigned for model initialization, reference time origin for tidal forcing, and model reference time for output NetCDF units attribute.<div class="box"> [[Variables#dstart\|DSTART]] = 365.0d0 ! days <span class="mediumOrchid">(ROMS is initialized on 2007-01-01 00:00:00Z)</span><br /> [[Variables#tide_start\|TIDE_START]] = 0.0d0 ! days <span class="mediumOrchid">(zero phase date is set when preparing the tidal data for 2006-01-01)</span><br /> [[Variables#time_ref\|TIME_REF]] = 20060101.0d0 ! yyyymmdd.dd <span class="mediumOrchid">(Very important: ROMS time is seconds since 2006-01-01 00:00:00Z)</span></div>

	Notice that all the parameters are an exact integer multiple from each other:		Notice that all the parameters are an exact integer multiple from each other:

Arango: /* Output Multi-Files */

2023-03-11T20:43:30Z

Output Multi-Files

← Older revision		Revision as of 20:43, 11 March 2023
Line 46:		Line 46:
	* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>		* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>

	* Timestamp assigned for model initialization, reference time origin for tidal forcing, and model reference time for output NetCDF units attribute.<div class="box"> [[Variables#dstart\|DSTART]] = 365.0d0 ! days <span class="mediumOrchid">(ROMS is initialized on 2007-01-01 00:00:00Z)</span><br /> [[Variables#tide_start\|TIDE_START]] = 0.0d0 ! days<br /> [[Variables#time_ref\|TIME_REF]] = 20060101.0d0 ! yyyymmdd.dd</div>		* Timestamp assigned for model initialization, reference time origin for tidal forcing, and model reference time for output NetCDF units attribute.<div class="box"> [[Variables#dstart\|DSTART]] = 365.0d0 ! days <span class="mediumOrchid">(ROMS is initialized on 2007-01-01 00:00:00Z)</span><br /> [[Variables#tide_start\|TIDE_START]] = 0.0d0 ! days<br /> [[Variables#time_ref\|TIME_REF]] = 20060101.0d0 ! yyyymmdd.dd <span class="mediumOrchid">(Very important: ROMS time is seconds since 2006-01-01 00:00:00Z)</span></div>

	Notice that all the parameters are an exact integer multiple from each other:		Notice that all the parameters are an exact integer multiple from each other:

Arango: /* Output Multi-Files */

2023-03-11T20:39:56Z

Output Multi-Files

← Older revision		Revision as of 20:39, 11 March 2023
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	* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>		* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>

	* Timestamp assigned for model initialization, reference time origin for tidal forcing, and model reference time for output NetCDF units attribute.<div class="box"> [[Variables#dstart\|DSTART]] = ~~366~~.0d0 ! days<br /> [[Variables#tide_start\|TIDE_START]] = 0.0d0 ! days<br /> [[Variables#time_ref\|TIME_REF]] = 20060101.0d0 ! yyyymmdd.dd</div>		* Timestamp assigned for model initialization, reference time origin for tidal forcing, and model reference time for output NetCDF units attribute.<div class="box"> [[Variables#dstart\|DSTART]] = 365.0d0 ! days <span class="mediumOrchid">(ROMS is initialized on 2007-01-01 00:00:00Z)</span><br /> [[Variables#tide_start\|TIDE_START]] = 0.0d0 ! days<br /> [[Variables#time_ref\|TIME_REF]] = 20060101.0d0 ! yyyymmdd.dd</div>

	Notice that all the parameters are an exact integer multiple from each other:		Notice that all the parameters are an exact integer multiple from each other:

Arango: /* Output Multi-Files */

2023-03-11T20:32:49Z

Output Multi-Files

← Older revision		Revision as of 20:32, 11 March 2023
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	* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>		* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>

	* Flags controlling the frequency of output.<div class="box"> [[Variables#nrrec\|NRREC]] = 0 ! Model restart flag<br /> [[Variables#LcycleRST\|LcycleRST]] == T ! Switch to recycle restart time records<br /> [[Variables#nRST\|NRST]] == 288 ! Number of timesteps between writing restart records <span class="mediumOrchid">(daily)</span><br /> [[Variables#nSTA\|NSTA]] == 1 ! Number of timesteps between stations records<br /> [[Variables#nFLT\|NFLT]] == 1 ! Number of timesteps between floats records<br /> [[Variables#ninfo\|NINFO]] == 1 ! Number of timesteps between printing information diagnostics</div>		* Flags controlling the frequency of output.<div class="box"> [[Variables#nrrec\|NRREC]] = 0 ! Model restart flag<br /> [[Variables#LcycleRST\|LcycleRST]] == T ! Switch to recycle restart time records <span class="mediumOrchid">(file with only 2 cycling time records)</span><br /> [[Variables#nRST\|NRST]] == 288 ! Number of timesteps between writing restart records <span class="mediumOrchid">(daily)</span><br /> [[Variables#nSTA\|NSTA]] == 1 ! Number of timesteps between stations records<br /> [[Variables#nFLT\|NFLT]] == 1 ! Number of timesteps between floats records<br /> [[Variables#ninfo\|NINFO]] == 1 ! Number of timesteps between printing information diagnostics</div>

	* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>		* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>

Arango: /* Output Multi-Files */

2023-03-11T20:26:49Z

Output Multi-Files

← Older revision		Revision as of 20:26, 11 March 2023
Line 53:		Line 53:
	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. If [[Variables#dstart\|DSTART]] is changed, it will reset the timestep internal counter <span class="red">iic(ng)</span>, and we are in deep trouble! Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

Arango: /* Output Multi-Files */

2023-03-11T20:21:58Z

Output Multi-Files

← Older revision		Revision as of 20:21, 11 March 2023
Line 51:		Line 51:
	<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>		<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>

	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the averages and diagnostic files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You cannot change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for ~~all~~ the restart of ROMS with multi-file. We need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]]. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

Arango: /* Output Multi-Files */

2023-03-11T20:13:50Z

Output Multi-Files

← Older revision		Revision as of 20:13, 11 March 2023
Line 38:		Line 38:
	Sometimes, it is advantageous to time-split ROMS output data (<span class="twilightBlue">averages</span>, <span class="twilightBlue">diagnostic</span>, <span class="twilightBlue">history</span>, and <span class="twilightBlue">quicksave</span>) into multiple NetCDF files to avoid creating huge files on disk for storage in applications with large grids. Smaller files are easy to handle and can be concatenated in OpenDAP catalogs.		Sometimes, it is advantageous to time-split ROMS output data (<span class="twilightBlue">averages</span>, <span class="twilightBlue">diagnostic</span>, <span class="twilightBlue">history</span>, and <span class="twilightBlue">quicksave</span>) into multiple NetCDF files to avoid creating huge files on disk for storage in applications with large grids. Smaller files are easy to handle and can be concatenated in OpenDAP catalogs.

	For example, an application for a particular ~~area~~ with a substantial grid size needs to be run for one year. The ROMS timestep is [[Variables#DT\|DT]] = 300 seconds. Then, one could split the <span class="twilightBlue">history</span> and quicksave data into daily NetCDF files with single or multiple time records every '''3''', '''6''', or '''24''' hours. In this case, ROMS will generate a sequence of files with suffixes <span class="violet">_0001.nc</span> to <span class="violet">_0365.nc</span> filenames. Therefore, we need the following parameters in [[roms.in\|roms.in]]:		For example, an application for a particular region with a substantial grid size needs to be run for one year. The ROMS timestep is [[Variables#DT\|DT]] = 300 seconds, as shown below. Then, one could split the <span class="twilightBlue">history</span> and <span class="twilightBlue">quicksave</span> output data into daily NetCDF files with single or multiple time records every '''3''', '''6''', or '''24''' hours. In this case, ROMS will generate a sequence of files with suffixes <span class="violet">_0001.nc</span> to <span class="violet">_0365.nc</span> filenames. Therefore, we need the following parameters in [[roms.in\|roms.in]]:

	* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>		* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>
Line 51:		Line 51:
	<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>		<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>

	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the averages and diagnostic files are single records files representing daily averaged fields.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the averages and diagnostic files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You cannot change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for all the restart of ROMS with multi-file. We need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You cannot change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for all the restart of ROMS with multi-file. We need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]]. If ~~doing~~ balancing terms and budgets, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]]. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

Arango: /* Output Multi-Files */

2023-03-11T19:56:46Z

Output Multi-Files

← Older revision		Revision as of 19:56, 11 March 2023
Line 36:		Line 36:
	==Output Multi-Files==		==Output Multi-Files==

	Sometimes, it is advantageous to time-split ROMS output (<span class="twilightBlue">averages</span>, <span class="twilightBlue">diagnostic</span>, <span class="twilightBlue">history</span>, and <span class="twilightBlue">quicksave</span>) into multiple NetCDF files to avoid creating huge files on disk for storage in applications with large grids. Smaller files are easy to handle and can be concatenated in OpenDAP catalogs.		Sometimes, it is advantageous to time-split ROMS output data (<span class="twilightBlue">averages</span>, <span class="twilightBlue">diagnostic</span>, <span class="twilightBlue">history</span>, and <span class="twilightBlue">quicksave</span>) into multiple NetCDF files to avoid creating huge files on disk for storage in applications with large grids. Smaller files are easy to handle and can be concatenated in OpenDAP catalogs.

	For example, an application for a particular area with a substantial grid size needs to be run for one year. The ROMS timestep is [[Variables#DT\|DT]] = 300 seconds. Then, one could split the <span class="twilightBlue">history</span> and quicksave data into daily NetCDF files with single or multiple time records every '''3''', '''6''', or '''24''' hours. In this case, ROMS will generate a sequence of files with suffixes <span class="violet">_0001.nc</span> to <span class="violet">_0365.nc</span> filenames. Therefore, we need the following parameters in [[roms.in\|roms.in]]:		For example, an application for a particular area with a substantial grid size needs to be run for one year. The ROMS timestep is [[Variables#DT\|DT]] = 300 seconds. Then, one could split the <span class="twilightBlue">history</span> and quicksave data into daily NetCDF files with single or multiple time records every '''3''', '''6''', or '''24''' hours. In this case, ROMS will generate a sequence of files with suffixes <span class="violet">_0001.nc</span> to <span class="violet">_0365.nc</span> filenames. Therefore, we need the following parameters in [[roms.in\|roms.in]]:

← Older revision		Revision as of 20:51, 11 March 2023
Line 51:		Line 51:
	<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>		<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>

	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain '''5'''-time records because of the initial conditions, and the rest of the files will have '''4'''-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain '''9'''-time records, and the rest will have '''8'''-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. If [[Variables#dstart\|DSTART]] is changed, it will reset the timestep internal counter <span class="red">iic(ng)</span>, and we are in deep trouble! Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. If [[Variables#dstart\|DSTART]] is changed, it will reset the timestep internal counter <span class="red">iic(ng)</span>, and we are in deep trouble! Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

← Older revision		Revision as of 20:32, 11 March 2023
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	* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>		* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>

	* Flags controlling the frequency of output.<div class="box"> [[Variables#nrrec\|NRREC]] = 0 ! Model restart flag<br /> [[Variables#LcycleRST\|LcycleRST]] == T ! Switch to recycle restart time records<br /> [[Variables#nRST\|NRST]] == 288 ! Number of timesteps between writing restart records <span class="mediumOrchid">(daily)</span><br /> [[Variables#nSTA\|NSTA]] == 1 ! Number of timesteps between stations records<br /> [[Variables#nFLT\|NFLT]] == 1 ! Number of timesteps between floats records<br /> [[Variables#ninfo\|NINFO]] == 1 ! Number of timesteps between printing information diagnostics</div>		* Flags controlling the frequency of output.<div class="box"> [[Variables#nrrec\|NRREC]] = 0 ! Model restart flag<br /> [[Variables#LcycleRST\|LcycleRST]] == T ! Switch to recycle restart time records <span class="mediumOrchid">(file with only 2 cycling time records)</span><br /> [[Variables#nRST\|NRST]] == 288 ! Number of timesteps between writing restart records <span class="mediumOrchid">(daily)</span><br /> [[Variables#nSTA\|NSTA]] == 1 ! Number of timesteps between stations records<br /> [[Variables#nFLT\|NFLT]] == 1 ! Number of timesteps between floats records<br /> [[Variables#ninfo\|NINFO]] == 1 ! Number of timesteps between printing information diagnostics</div>

	* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>		* Output history, average, and diagnostic file parameters.<div class="box"> [[Variables#ldefout\|LDEFOUT]] == T ! File creation/append switch<br /> [[Variables#nHIS\|NHIS]] == 72 ! Number of timesteps between writing history records <span class="mediumOrchid">(every 6 hours)</span><br /> [[Variables#ndefHIS\|NDEFHIS]] == 288 ! Number of timesteps between the creation of new history files <span class="mediumOrchid">(daily files)</span><br /> [[Variables#nQCK\|NQCK]] == 36 ! Number of timesteps between writing quicksave records <span class="mediumOrchid">(every 3 hours)</span><br /> [[Variables#ndefQCK\|NDEFQCK]] == 288 ! Number of timesteps between the creation of new quicksave file <span class="mediumOrchid">(daily)</span><span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsAVG\|NTSAVG]] == 1 ! Starting averages timestep<br /> [[Variables#nAVG\|NAVG]] == 288 ! Number of timesteps between writing averages records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefAVG\|NDEFAVG]] == 288 ! Number of timesteps between the creation of new averages file <span class="mediumOrchid">(daily, single record files)</span><br /> [[Variables#ntsDIA\|NTSDIA]] == 1 ! Starting diagnostics timestep<br /> [[Variables#nDIA\|NDIA]] == 288 ! Number of timesteps between writing diagnostics records <span class="mediumOrchid">(daily averages)</span><br /> [[Variables#ndefDIA\|NDEFDIA]] == 288 ! Number of timesteps between the creation of new diagnostics file <span class="mediumOrchid">(daily, single record files)</span></div>

← Older revision		Revision as of 20:26, 11 March 2023
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	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. If [[Variables#dstart\|DSTART]] is changed, it will reset the timestep internal counter <span class="red">iic(ng)</span>, and we are in deep trouble! Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

← Older revision		Revision as of 20:21, 11 March 2023
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	<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>		<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>

	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the averages and diagnostic files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the <span class="twilightBlue">averages</span> and <span class="twilightBlue">diagnostic</span> files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You cannot change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for ~~all~~ the restart of ROMS with multi-file. We need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You '''cannot''' change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for the restart of ROMS with multi-file. In addition, we need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]]. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]] because of the accumulation sums when computing time-averaging fields. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

← Older revision		Revision as of 20:13, 11 March 2023
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	Sometimes, it is advantageous to time-split ROMS output data (<span class="twilightBlue">averages</span>, <span class="twilightBlue">diagnostic</span>, <span class="twilightBlue">history</span>, and <span class="twilightBlue">quicksave</span>) into multiple NetCDF files to avoid creating huge files on disk for storage in applications with large grids. Smaller files are easy to handle and can be concatenated in OpenDAP catalogs.		Sometimes, it is advantageous to time-split ROMS output data (<span class="twilightBlue">averages</span>, <span class="twilightBlue">diagnostic</span>, <span class="twilightBlue">history</span>, and <span class="twilightBlue">quicksave</span>) into multiple NetCDF files to avoid creating huge files on disk for storage in applications with large grids. Smaller files are easy to handle and can be concatenated in OpenDAP catalogs.

	For example, an application for a particular ~~area~~ with a substantial grid size needs to be run for one year. The ROMS timestep is [[Variables#DT\|DT]] = 300 seconds. Then, one could split the <span class="twilightBlue">history</span> and quicksave data into daily NetCDF files with single or multiple time records every '''3''', '''6''', or '''24''' hours. In this case, ROMS will generate a sequence of files with suffixes <span class="violet">_0001.nc</span> to <span class="violet">_0365.nc</span> filenames. Therefore, we need the following parameters in [[roms.in\|roms.in]]:		For example, an application for a particular region with a substantial grid size needs to be run for one year. The ROMS timestep is [[Variables#DT\|DT]] = 300 seconds, as shown below. Then, one could split the <span class="twilightBlue">history</span> and <span class="twilightBlue">quicksave</span> output data into daily NetCDF files with single or multiple time records every '''3''', '''6''', or '''24''' hours. In this case, ROMS will generate a sequence of files with suffixes <span class="violet">_0001.nc</span> to <span class="violet">_0365.nc</span> filenames. Therefore, we need the following parameters in [[roms.in\|roms.in]]:

	* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>		* Timestepping parameters.<div class="box"> [[Variables#ntimes\|NTIMES]] = 105120 ! Number of timesteps <span class="mediumOrchid">(288 steps per day; 365 days simulation)</span><br /> [[Variables#dt\|DT]] == 300.0d0 ! Timestep size (seconds)<br /> [[Variables#ndtfast\|NDTFAST]] == 30 ! Number of barotropic steps</div>
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	<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>		<div class="box"> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFHIS]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefHIS\|NDEFQCK]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefAVG\|NDEFAVG]]) = 0 <br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#ndefDIA\|NDEFDIA]]) = 0 <br /><br /> MOD([[Variables#ntimes\|NTIMES]], [[Variables#nRST\|NRST]]) = 0 <br /><br /> MOD([[Variables#ndefHIS\|NDEFHIS]], [[Variables#nHIS\|NHIS]]) = 0 <br /> MOD([[Variables#ndefQCK\|NDEFQCK]], [[Variables#nQCK\|NQCK]]) = 0 <br /> MOD([[Variables#ndefAVH\|NDEFAVG]], [[Variables#nAVG\|NAVG]]) = 0 <br /> MOD([[Variables#ndefDIA\|NDEFDIA]], [[Variables#nHIS\|NDIA]]) = 0 <br /></div>

	where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the averages and diagnostic files are single records files representing daily averaged fields.		where the Fortran intrinsic function '''MOD(<span class="red">X</span>,<span class="red">Y</span>)''' computes the remainder of the division of <span class="red">X</span> by <span class="red">Y</span>, and has to be always '''zero''' for ROMS multi-file option to work. Notice that the first files in the <span class="twilightBlue">history</span> data series (<span class="violet">roms_his_0001.nc</span>) will contain 5-time records because of the initial conditions, and the rest of the files will have 4-time records. Similarly, the first file in the <span class="twilightBlue">quicksave</span> series (<span class="violet">roms_qck_0001.nc</span>) will contain 9-time records, and the rest will have 8-time records. The time-averaged data in the averages and diagnostic files are single records files representing daily averaged fields. The above analysis also holds when converted to time in seconds since every parameter is multiplied by the [[Variables#dt\|DT]] timestep.

	<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You cannot change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for all the restart of ROMS with multi-file. We need the following mathematical equalities:		<span class="red">WARNING:</span> If running your application in a supercomputer with limited-time job queues, long simulations will require a restart. You cannot change the values of [[Variables#ntimes\|NTIMES]] or [[Variables#dstart\|DSTART]] because the multi-file will fail. Notice that the value [[Variables#nRST\|NRST]] is crucial for all the restart of ROMS with multi-file. We need the following mathematical equalities:
	<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>		<div class="box"> MOD([[Variables#nRST\|NRST]], [[Variables#nHIS\|NHIS]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nQCK\|NQCK]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nAVG\|NAVG]]) = 0<br /> MOD([[Variables#nRST\|NRST]], [[Variables#nDIA\|NDIA]]) = 0<br /></div>
	Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]]. If ~~doing~~ balancing terms and budgets, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.		Also, it will be trivial to restart if [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] = [[Variables#nRST\|NRST]]. If balancing terms and budgets from output data, you will need [[Variables#nAVG\|NAVG]] = [[Variables#nDIA\|NDIA]] too.

← Older revision		Revision as of 18:18, 5 May 2025
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	<div class="title">ROMS I/O</div>		<div class="title">ROMS I/O</div>

	ROMS uses NetCDF for all its input and output data management. The NetCDF files can be processed using the standard library developed by [http://doi.org/10.5065/D6H70CW6 UNIDATA], the Parallel-IO ('''PIO''') library developed at NCAR (Hartnett and Edwards, 2021; [https://www.researchgate.net/publication/348169990_THE_PARALLELIO_PIO_CFORTRAN_LIBRARIES_FOR_SCALABLE_HPC_PERFORMANCE unpublished paper]), or the Software for Cashing Output and Reads for Parallel I/O ('''SCORPIO''') library intended for the DOE's Energy Exascale Earth Model System ([https://e3sm.org/scorpio-parallel-io-library/ E<sup>3</sup>SM]). Furthermore, another parallel I/O strategy has been available in ROMS for several years with the NetCDF4/HDF5 libraries by activating the [[Options#PARALLEL_IO\|PARALLEL_IO]] and [[Options#HDF5\|HDF5]] CPP options.		ROMS uses NetCDF for all its input and output data management. The NetCDF files can be processed using the standard library developed by [http://doi.org/10.5065/D6H70CW6 UNIDATA], the Parallel-IO ('''PIO''') library developed at NCAR (Hartnett and Edwards, 2021; [https://www.researchgate.net/publication/348169990_THE_PARALLELIO_PIO_CFORTRAN_LIBRARIES_FOR_SCALABLE_HPC_PERFORMANCE unpublished paper]). Furthermore, another parallel I/O strategy has been available in ROMS for several years with the NetCDF4/HDF5 libraries by activating the [[Options#PARALLEL_IO\|PARALLEL_IO]] and [[Options#HDF5\|HDF5]] CPP options.

	The '''SCORPIO''' library was forked from the '''PIO''' library several years ago and evolved separately. The generic interface for parallel I/O in ROMS works for both the '''PIO''' or '''SCORPIO''' libraries and available by activating the [[Options#PIO_LIB\|PIO_LIB]] CPP option. <span class="red">However</span>, we recommend using the '''PIO''' library because it is more efficient in processing I/O in our benchmark tests.

	Generally, writing is usually a more frequent and more complicated operation than reading. There are four strategies for writing (Mendez ''et al.'', 2019; [https://www.researchgate.net/publication/332190037_Best_Practice_Guide_-_Parallel_IO Preprint]):		Generally, writing is usually a more frequent and more complicated operation than reading. There are four strategies for writing (Mendez ''et al.'', 2019; [https://www.researchgate.net/publication/332190037_Best_Practice_Guide_-_Parallel_IO Preprint]):
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	#<span class="blue">Single file, single writer:</span> '''Serial I/O''' in non-parallel or parallel applications. It is the default strategy in ROMS using the '''NetCDF3''' or '''NetCDF4''' libraries.		#<span class="blue">Single file, single writer:</span> '''Serial I/O''' in non-parallel or parallel applications. It is the default strategy in ROMS using the '''NetCDF3''' or '''NetCDF4''' libraries.
	#<span class="blue">Single file, multiple writers:</span> '''Parallel I/O''' with each partition tile writing its data to a single file. In ROMS, this capability is achieved by activating [[Options#PARALLEL_IO\|PARALLEL_IO]] and [[Options#HDF5\|HDF5]]. It is only possible with the '''NetCDF4/HDF5''' libraries.		#<span class="blue">Single file, multiple writers:</span> '''Parallel I/O''' with each partition tile writing its data to a single file. In ROMS, this capability is achieved by activating [[Options#PARALLEL_IO\|PARALLEL_IO]] and [[Options#HDF5\|HDF5]]. It is only possible with the '''NetCDF4/HDF5''' libraries.
	#<span class="blue">Single file, collective writers:</span> '''Parallel I/O''' with either one or a subset of processes performing I/O operations. The I/O operations can be '''synchronous''' or '''asynchronous'''. In ROMS, this capability uses the '''PIO''' ~~or '''SCORPIO''' libraries~~ and available when [[Options#PIO_LIB\|PIO_LIB]] is activated.		#<span class="blue">Single file, collective writers:</span> '''Parallel I/O''' with either one or a subset of processes performing I/O operations. The I/O operations can be '''synchronous''' or '''asynchronous'''. In ROMS, this capability uses the '''PIO''' library and is available when [[Options#PIO_LIB\|PIO_LIB]] is activated.
	#<span class="blue">Multiple files, multiple writers:</span> '''Parallel I/O''' in which each distributed-memory or shared-memory tile decomposition writes its data into the partition file. Still, post-processing is required to pack the data into a single file. Currently, this capability is not available in ROMS but can be easily implemented within its current I/O infrastructure. However, this strategy is cumbersome and undesired in variational data assimilation (4D-Var) algorithms that require reading forwards and backward, in time, the state trajectories. As a consequence, reading becomes the bottleneck.		#<span class="blue">Multiple files, multiple writers:</span> '''Parallel I/O''' in which each distributed-memory or shared-memory tile decomposition writes its data into the partition file. Still, post-processing is required to pack the data into a single file. Currently, this capability is not available in ROMS but can be easily implemented within its current I/O infrastructure. However, this strategy is cumbersome and undesired in variational data assimilation (4D-Var) algorithms that require reading forwards and backward, in time, the state trajectories. As a consequence, reading becomes the bottleneck.

Line 20:		Line 18:
	Parallel I/O using parallel HDF5 and NetCDF-4 has been available in ROMS for many years. This I/O option requires parallel enabled HDF5 and NetCDF-4 and is activated by defining [[Options#PARALLEL_IO\|PARALLEL_IO]] and [[Options#HDF5\|HDF5]] CPP options. Each parallel tile reads and writes the decomposed data. This approach does not scale well because it requires every process to participate in reading and writing, which quickly overloads the file system with requests as the number of tiles (NtileI x NtileJ) increases.		Parallel I/O using parallel HDF5 and NetCDF-4 has been available in ROMS for many years. This I/O option requires parallel enabled HDF5 and NetCDF-4 and is activated by defining [[Options#PARALLEL_IO\|PARALLEL_IO]] and [[Options#HDF5\|HDF5]] CPP options. Each parallel tile reads and writes the decomposed data. This approach does not scale well because it requires every process to participate in reading and writing, which quickly overloads the file system with requests as the number of tiles (NtileI x NtileJ) increases.

	==Parallel I/O with PIO ~~or SCORPIO~~==		==Parallel I/O with PIO==

	'''PIO''' ~~and '''SCORPIO''' libraries are~~ primarily intended for ROMS '''distributed-memory (MPI) applications''' running on a large number of processes in an HPC system with a Parallel File System (like Lustre, GPFS, and so on) for high-performance I/O. The '''PIO~~''' and '''SCORPIO~~''' library uses the '''MPI-IO''' interface to facilitate the partitioning of the data across computational or dedicated I/O processes. For example, in an HPC cluster environment with a '''Parallel File System''', the user can instruct '''PIO~~''' or '''SCORPIO~~''' to designate which processes per node to perform I/O. This is a much more reasonable approach for larger applications running on hundreds of processors. To use this Parallel I/O strategy, the '''PIO~~''' or '''SCORPIO~~''' library must be linked to ROMS at compile time by defining the [[Options#PIO_LIB\|PIO_LIB]] CPP option. <span class="blue">It is only available in distributed-memory applications since it uses '''MPI-IO'''</span>.		The '''PIO''' library is primarily intended for ROMS '''distributed-memory (MPI) applications''' running on a large number of processes in an HPC system with a Parallel File System (like Lustre, GPFS, and so on) for high-performance I/O. The '''PIO''' library uses the '''MPI-IO''' interface to facilitate the partitioning of the data across computational or dedicated I/O processes. For example, in an HPC cluster environment with a '''Parallel File System''', the user can instruct '''PIO''' to designate which processes per node to perform I/O. This is a much more reasonable approach for larger applications running on hundreds of processors. To use this Parallel I/O strategy, the '''PIO''' library must be linked to ROMS at compile time by defining the [[Options#PIO_LIB\|PIO_LIB]] CPP option. <span class="blue">It is only available in distributed-memory applications since it uses '''MPI-IO'''</span>.

	There are two modes of parallel I/O in '''PIO~~''' and '''SCORPIO~~''':		There are two modes of parallel I/O in '''PIO''':

	<ol style="list-style-type: upper-alpha">		<ol style="list-style-type: upper-alpha">
	<li>'''Synchronous:''' MPI intra-communications mode. A subset or all processes does I/O and also computations. The user specifies the total number of I/O tasks and how they are distributed across the HPC nodes as a function of the ROMS MPI-communicator object, '''OCN_COMM_WORLD'''. It is often desirable to shift the first I/O task away from the first computation task since it has higher memory requirements than other processes. If the MPI processes are spread over several computer nodes, it is highly recommended to spread all I/O tasks over all nodes. Avoid all I/O processes occupying the same node.</li>		<li>'''Synchronous:''' MPI intra-communications mode. A subset or all processes does I/O and also computations. The user specifies the total number of I/O tasks and how they are distributed across the HPC nodes as a function of the ROMS MPI-communicator object, '''OCN_COMM_WORLD'''. It is often desirable to shift the first I/O task away from the first computation task since it has higher memory requirements than other processes. If the MPI processes are spread over several computer nodes, it is highly recommended to spread all I/O tasks over all nodes. Avoid all I/O processes occupying the same node.</li>
	<li>'''Asynchronous:''' MPI inter-communications mode. The I/O tasks are a disjointed set of dedicated I/O processes and do not perform computations. It is possible to have groups of computational units running separate models (coupling) where all the I/O data are sent to dedicated processes. In ROMS, the asynchronous mode is possible by ~~activation either~~ [[Options#ASYNCHRONOUS_PIO\|ASYNCHRONOUS_PIO~~]] or [[Options#ASYNCHRONOUS_SCORPIO\|ASYNCHRONOUS_SCORPIO~~]]. '''<span class="red">However</span>, this capability is still under development and not recommended for use at this time.'''</li>		<li>'''Asynchronous:''' MPI inter-communications mode. The I/O tasks are a disjointed set of dedicated I/O processes and do not perform computations. It is possible to have groups of computational units running separate models (coupling) where all the I/O data are sent to dedicated processes. In ROMS, the asynchronous mode is possible by activating [[Options#ASYNCHRONOUS_PIO\|ASYNCHRONOUS_PIO]]. '''<span class="red">However</span>, this capability is still under development and not recommended for use at this time.'''</li>
	</ol>		</ol>