fix compilation error (#5061)

Author: dzzz2001

source/module_hamilt_lcao/module_gint/gint_force_gpu.cu

@@ -31,7 +31,11 @@ void gint_fvl_gpu(const hamilt::HContainer<double>* dm,
                         const Grid_Technique& gridt,
                         const UnitCell& ucell)
 { 
-    int dev_id = base_device::information::set_device_by_rank();
+#ifdef __MPI
+    const int dev_id = base_device::information::set_device_by_rank();
+#else
+    const int dev_id = 0;
+#endif
     // checkCuda(cudaSetDeviceFlags(cudaDeviceScheduleBlockingSync));
 
     const int nbzp = gridt.nbzp;

source/module_hamilt_lcao/module_gint/gint_rho_gpu.cu

@@ -17,7 +17,11 @@ void gint_rho_gpu(const hamilt::HContainer<double>* dm,
                         const UnitCell& ucell,
                         double* rho)
 {
-    int dev_id = base_device::information::set_device_by_rank();
+#ifdef __MPI
+    const int dev_id = base_device::information::set_device_by_rank();
+#else
+    const int dev_id = 0;
+#endif
     // checkCuda(cudaSetDeviceFlags(cudaDeviceScheduleBlockingSync));
 
     const int nbzp = gridt.nbzp;

source/module_hamilt_lcao/module_gint/gint_vl_gpu.cu

@@ -29,7 +29,11 @@ void gint_vl_gpu(hamilt::HContainer<double>* hRGint,
                  double* pvpR,
                  const bool is_gamma_only)
 {
-    int dev_id = base_device::information::set_device_by_rank();
+#ifdef __MPI
+    const int dev_id = base_device::information::set_device_by_rank();
+#else
+    const int dev_id = 0;
+#endif
     // checkCuda(cudaSetDeviceFlags(cudaDeviceScheduleBlockingSync));
     const int nbzp = gridt.nbzp;
     const int num_streams = gridt.nstreams;

source/module_hamilt_lcao/module_gint/grid_technique.cpp

@@ -560,8 +560,6 @@ int Grid_Technique::find_offset(const int id1, const int id2, const int iat1, co
 
 void Grid_Technique::init_gpu_gint_variables(const UnitCell& ucell,
                                              const int num_stream) {
-
-    int dev_id = base_device::information::set_device_by_rank();
     if (is_malloced) {
         free_gpu_gint_variables(this->nat);
     }