Tried to set different backends

Author: rezgarshakeri

examples/Hdiv-mixed/include/structs.h

@@ -40,6 +40,7 @@ struct CeedData_ {
 // Application context from user command line options
 typedef struct AppCtx_ *AppCtx;
 struct AppCtx_ {
+  char              ceed_resource[PETSC_MAX_PATH_LEN]; // libCEED backend
   MPI_Comm          comm;
   // Degree of polynomial (1 only), extra quadrature pts
   PetscInt          degree;

examples/Hdiv-mixed/main.c

@@ -40,29 +40,6 @@ int main(int argc, char **argv) {
   // ---------------------------------------------------------------------------
   PetscCall( PetscInitialize(&argc, &argv, NULL, help) );
 
-  // ---------------------------------------------------------------------------
-  // Initialize libCEED
-  // ---------------------------------------------------------------------------
-  // -- Initialize backend
-  Ceed ceed;
-  CeedInit("/cpu/self/ref/serial", &ceed);
-  CeedMemType mem_type_backend;
-  CeedGetPreferredMemType(ceed, &mem_type_backend);
-
-  VecType        vec_type = NULL;
-  switch (mem_type_backend) {
-  case CEED_MEM_HOST: vec_type = VECSTANDARD; break;
-  case CEED_MEM_DEVICE: {
-    const char *resolved;
-    CeedGetResource(ceed, &resolved);
-    if (strstr(resolved, "/gpu/cuda")) vec_type = VECCUDA;
-    else if (strstr(resolved, "/gpu/hip/occa"))
-      vec_type = VECSTANDARD; // https://github.com/CEED/libCEED/issues/678
-    else if (strstr(resolved, "/gpu/hip")) vec_type = VECHIP;
-    else vec_type = VECSTANDARD;
-  }
-  }
-
   // ---------------------------------------------------------------------------
   // Create structs
   // ---------------------------------------------------------------------------
@@ -101,6 +78,30 @@ int main(int argc, char **argv) {
   app_ctx->ctx_Hdiv = ctx_Hdiv;
   app_ctx->ctx_H1 = ctx_H1;
 
+  // ---------------------------------------------------------------------------
+  // Initialize libCEED
+  // ---------------------------------------------------------------------------
+  // -- Initialize backend
+  Ceed ceed;
+  //CeedInit("/cpu/self/ref/serial", &ceed);
+  CeedInit(app_ctx->ceed_resource, &ceed);
+  CeedMemType mem_type_backend;
+  CeedGetPreferredMemType(ceed, &mem_type_backend);
+
+  VecType        vec_type = NULL;
+  switch (mem_type_backend) {
+  case CEED_MEM_HOST: vec_type = VECSTANDARD; break;
+  case CEED_MEM_DEVICE: {
+    const char *resolved;
+    CeedGetResource(ceed, &resolved);
+    if (strstr(resolved, "/gpu/cuda")) vec_type = VECCUDA;
+    else if (strstr(resolved, "/gpu/hip/occa"))
+      vec_type = VECSTANDARD; // https://github.com/CEED/libCEED/issues/678
+    else if (strstr(resolved, "/gpu/hip")) vec_type = VECHIP;
+    else vec_type = VECSTANDARD;
+  }
+  }
+
   // -- Process general command line options
   MPI_Comm comm = PETSC_COMM_WORLD;
   // ---------------------------------------------------------------------------

examples/Hdiv-mixed/src/cl-options.c

@@ -23,11 +23,22 @@
 PetscErrorCode ProcessCommandLineOptions(AppCtx app_ctx) {
 
   PetscBool problem_flag = PETSC_FALSE;
+  PetscBool ceed_flag = PETSC_FALSE;
   PetscFunctionBeginUser;
 
   PetscOptionsBegin(app_ctx->comm, NULL, "H(div) examples in PETSc with libCEED",
                     NULL);
 
+  PetscCall( PetscOptionsString("-ceed", "CEED resource specifier",
+                                NULL, app_ctx->ceed_resource, app_ctx->ceed_resource,
+                                sizeof(app_ctx->ceed_resource), &ceed_flag) );
+
+  // Provide default ceed resource if not specified
+  if (!ceed_flag) {
+    const char *ceed_resource = "/cpu/self";
+    strncpy(app_ctx->ceed_resource, ceed_resource, 10);
+  }
+
   PetscCall( PetscOptionsFList("-problem", "Problem to solve", NULL,
                                app_ctx->problems,
                                app_ctx->problem_name, app_ctx->problem_name, sizeof(app_ctx->problem_name),