+/*! Selects the Ewald kernel type, analytical on SM 3.0 and later, tabulated on
+ earlier GPUs, single or twin cut-off. */
+static int pick_ewald_kernel_type(bool bTwinCut,
+ const cuda_dev_info_t *dev_info)
+{
+ bool bUseAnalyticalEwald, bForceAnalyticalEwald, bForceTabulatedEwald;
+ int kernel_type;
+
+ /* Benchmarking/development environment variables to force the use of
+ analytical or tabulated Ewald kernel. */
+ bForceAnalyticalEwald = (getenv("GMX_CUDA_NB_ANA_EWALD") != NULL);
+ bForceTabulatedEwald = (getenv("GMX_CUDA_NB_TAB_EWALD") != NULL);
+
+ if (bForceAnalyticalEwald && bForceTabulatedEwald)
+ {
+ gmx_incons("Both analytical and tabulated Ewald CUDA non-bonded kernels "
+ "requested through environment variables.");
+ }
+
+ /* By default, on SM 3.0 and later use analytical Ewald, on earlier tabulated. */
+ if ((dev_info->prop.major >= 3 || bForceAnalyticalEwald) && !bForceTabulatedEwald)
+ {
+ bUseAnalyticalEwald = true;
+
+ if (debug)
+ {
+ fprintf(debug, "Using analytical Ewald CUDA kernels\n");
+ }
+ }
+ else
+ {
+ bUseAnalyticalEwald = false;
+
+ if (debug)
+ {
+ fprintf(debug, "Using tabulated Ewald CUDA kernels\n");
+ }
+ }
+
+ /* Use twin cut-off kernels if requested by bTwinCut or the env. var.
+ forces it (use it for debugging/benchmarking only). */
+ if (!bTwinCut && (getenv("GMX_CUDA_NB_EWALD_TWINCUT") == NULL))
+ {
+ kernel_type = bUseAnalyticalEwald ? eelCuEWALD_ANA : eelCuEWALD_TAB;
+ }
+ else
+ {
+ kernel_type = bUseAnalyticalEwald ? eelCuEWALD_ANA_TWIN : eelCuEWALD_TAB_TWIN;
+ }
+
+ return kernel_type;
+}
+
+