Merge branch release-5-0

[alexxy/gromacs.git] / src / programs / mdrun / runner.cpp

diff --git a/src/programs/mdrun/runner.cpp b/src/programs/mdrun/runner.cpp
index 3699360ead0295e831d6ecd7ae2491129a62d7d9..d9d2fd26776360f0ef83431cb852d9e380d75940 100644 (file)
--- a/src/programs/mdrun/runner.cpp
+++ b/src/programs/mdrun/runner.cpp
@@ -959,7 +959,7 @@ int mdrunner(gmx_hw_opt_t *hw_opt,
              int repl_ex_seed, real pforce, real cpt_period, real max_hours,
              const char *deviceOptions, int imdport, unsigned long Flags)
 {
-    gmx_bool                  bForceUseGPU, bTryUseGPU;
+    gmx_bool                  bForceUseGPU, bTryUseGPU, bRerunMD, bCantUseGPU;
     t_inputrec               *inputrec;
     t_state                  *state = NULL;
     matrix                    box;
@@ -999,8 +999,20 @@ int mdrunner(gmx_hw_opt_t *hw_opt,
         fplog = NULL;
     }
 
+    bRerunMD     = (Flags & MD_RERUN);
     bForceUseGPU = (strncmp(nbpu_opt, "gpu", 3) == 0);
     bTryUseGPU   = (strncmp(nbpu_opt, "auto", 4) == 0) || bForceUseGPU;
+    /* Rerun execution time is dominated by I/O and pair search, so
+     * GPUs are not very useful, plus they do not support more than
+     * one energy group. Don't select them when they can't be used,
+     * unless the user requested it, then fatal_error is called later.
+     *
+     * TODO it would be nice to notify the user that if this check
+     * causes GPUs not to be used that this is what is happening, and
+     * why, but that will be easier to do after some future
+     * cleanup. */
+    bCantUseGPU = bRerunMD && (inputrec->opts.ngener > 1);
+    bTryUseGPU  = bTryUseGPU && !(bCantUseGPU && !bForceUseGPU);
 
     /* Detect hardware, gather information. This is an operation that is
      * global for this process (MPI rank). */
@@ -1186,7 +1198,7 @@ int mdrunner(gmx_hw_opt_t *hw_opt,
                   );
     }
 
-    if ((Flags & MD_RERUN) &&
+    if (bRerunMD &&
         (EI_ENERGY_MINIMIZATION(inputrec->eI) || eiNM == inputrec->eI))
     {
         gmx_fatal(FARGS, "The .mdp file specified an energy mininization or normal mode algorithm, and these are not compatible with mdrun -rerun");