Changes between Initial Version and Version 1 of Ticket #967
- Timestamp:
- 06/28/24 21:57:53 (10 months ago)
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Ticket #967 – Description
initial v1 1 1 A few routines were updated to allow compiling and running **split 4D-Var** with mixed precision. 2 2 3 The **split 4D-Var** algorithms (like **RBL4DVAR_SPLIT**) recommend the mixed precision approach to accelerate computations. The executing script (see **submit_split_rbl4dvar.sh**) uses multiple **ROMS** executables, which runs the **outer loop** in double precision (nonlinear background trajectory, **prior**) and single precision in the **inner loops** (tangent linear and adjoint minimization, incrementphase).3 The **split 4D-Var** algorithms (like **RBL4DVAR_SPLIT**) recommend the mixed precision approach to accelerate computations. The executing script (see **submit_split_rbl4dvar.sh**) uses multiple **ROMS** executables, which runs the **outer loop** in double precision (nonlinear background trajectory, **prior**) and single precision in the **inner loops** (tangent linear and adjoint minimization, **increment** phase). 4 4 5 5 In this update, several of the variables needed by the **RPCG** solver are declared in double precision to reduce the impact of rounding error and the convergence of the minimization algorithm (**rpcg_lanczos.F**) when computing dot-products and Ritz eigenvalues and eigenvectors.