swap the sizeof() be the first multiplier to avoid overflow of int (#5561)

Author: kirk0830

source/module_hamilt_pw/hamilt_pwdft/wavefunc.cpp

@@ -59,12 +59,18 @@ psi::Psi<std::complex<double>>* wavefunc::allocate(const int nkstot, const int n
         if (PARAM.inp.basis_type == "lcao_in_pw")
         {
             wanf2[0].create(PARAM.globalv.nlocal, npwx * PARAM.globalv.npol);
-            const size_t memory_cost = PARAM.globalv.nlocal * (PARAM.globalv.npol * npwx) * sizeof(std::complex<double>);
-            std::cout << " Memory for wanf2 (MB): " << double(memory_cost) / 1024.0 / 1024.0 << std::endl;
+
+            // WARNING: put the sizeof() be the first to avoid the overflow of the multiplication of int
+            const size_t memory_cost = sizeof(std::complex<double>) * PARAM.globalv.nlocal * (PARAM.globalv.npol * npwx);
+
+            std::cout << " Memory for wanf2 (MB): " << static_cast<double>(memory_cost) / 1024.0 / 1024.0 << std::endl;
             ModuleBase::Memory::record("WF::wanf2", memory_cost);
         }
-        const size_t memory_cost = PARAM.inp.nbands * (PARAM.globalv.npol * npwx) * sizeof(std::complex<double>);
-        std::cout << " MEMORY FOR PSI (MB)  : " << double(memory_cost) / 1024.0 / 1024.0 << std::endl;
+        
+        // WARNING: put the sizeof() be the first to avoid the overflow of the multiplication of int
+        const size_t memory_cost = sizeof(std::complex<double>) * PARAM.inp.nbands * (PARAM.globalv.npol * npwx);
+
+        std::cout << " MEMORY FOR PSI (MB)  : " << static_cast<double>(memory_cost) / 1024.0 / 1024.0 << std::endl;
         ModuleBase::Memory::record("Psi_PW", memory_cost);
     }
     else if (PARAM.inp.basis_type != "pw")
@@ -82,17 +88,22 @@ psi::Psi<std::complex<double>>* wavefunc::allocate(const int nkstot, const int n
                 this->wanf2[ik].create(PARAM.globalv.nlocal, npwx * PARAM.globalv.npol);
             }
 
-            const size_t memory_cost = nks2 * PARAM.globalv.nlocal * (npwx * PARAM.globalv.npol) * sizeof(std::complex<double>);
-            std::cout << " Memory for wanf2 (MB): " << double(memory_cost) / 1024.0 / 1024.0 << std::endl;
+            // WARNING: put the sizeof() be the first to avoid the overflow of the multiplication of int
+            const size_t memory_cost = sizeof(std::complex<double>) * nks2 * PARAM.globalv.nlocal * (npwx * PARAM.globalv.npol);
+
+            std::cout << " Memory for wanf2 (MB): " << static_cast<double>(memory_cost) / 1024.0 / 1024.0 << std::endl;
             ModuleBase::Memory::record("WF::wanf2", memory_cost);
         }
     }
     else
     {
         // initial psi rather than evc
         psi_out = new psi::Psi<std::complex<double>>(nks2, PARAM.inp.nbands, npwx * PARAM.globalv.npol, ngk);
-        const size_t memory_cost = nks2 * PARAM.inp.nbands * (PARAM.globalv.npol * npwx) * sizeof(std::complex<double>);
-        std::cout << " MEMORY FOR PSI (MB)  : " << double(memory_cost) / 1024.0 / 1024.0 << std::endl;
+
+        // WARNING: put the sizeof() be the first to avoid the overflow of the multiplication of int
+        const size_t memory_cost = sizeof(std::complex<double>) * nks2 * PARAM.inp.nbands * (PARAM.globalv.npol * npwx);
+
+        std::cout << " MEMORY FOR PSI (MB)  : " << static_cast<double>(memory_cost) / 1024.0 / 1024.0 << std::endl;
         ModuleBase::Memory::record("Psi_PW", memory_cost);
     }
     return psi_out;

source/module_psi/psi_initializer.cpp

@@ -73,8 +73,8 @@ psi::Psi<std::complex<double>>* psi_initializer<T, Device>::allocate(const bool
                                                      PARAM.inp.nbands, // because no matter what, the wavefunction finally needed has PARAM.inp.nbands bands
                                                      nbasis_actual, 
                                                      this->pw_wfc_->npwk);
-        double memory_cost_psi = nks_psi * PARAM.inp.nbands * this->pw_wfc_->npwk_max * PARAM.globalv.npol*
-                        sizeof(std::complex<double>);
+        double memory_cost_psi = sizeof(std::complex<double>) * nks_psi * PARAM.inp.nbands 
+                                                              * this->pw_wfc_->npwk_max * PARAM.globalv.npol;
 #ifdef __MPI
         // get the correct memory cost for psi by all-reduce sum
         Parallel_Reduce::reduce_all(memory_cost_psi);