modify warning output (#6074)

Author: dzzz2001

source/module_io/read_input_item_elec_stru.cpp

@@ -122,9 +122,23 @@ void ReadInput::item_elec_stru()
                 }
                 else if (ks_solver == "cusolver" || ks_solver == "cusolvermp")
                 {
+                    std::string warningstr;
 #ifndef __MPI
                     ModuleBase::WARNING_QUIT("ReadInput", "Cusolver can not be used for series version.");
 #endif
+#ifndef __CUDA
+                    warningstr = "ks_solver is set to " + ks_solver + " but ABACUS is built with CPU only!\n"
+                    + " Please rebuild ABACUS with GPU support or change the ks_solver.";  
+                    ModuleBase::WARNING_QUIT("ReadInput", warningstr);
+#endif
+                    if( ks_solver == "cusolvermp")
+                    {
+#ifndef __CUSOLVERMP
+                    warningstr = "ks_solver is set to cusolvermp, but ABACUS is not built with cusolvermp support\n"
+                    " Please rebuild ABACUS with cusolvermp support or change the ks_solver.";
+                    ModuleBase::WARNING_QUIT("ReadInput", warningstr);
+#endif              
+                    }
                 }
                 else if (ks_solver == "pexsi")
                 {