Fix numerical error in DeePKS vdrpre.

Author: ErjieWu

source/source_lcao/module_deepks/deepks_vdrpre.cpp

@@ -153,7 +153,7 @@ void DeePKS_domain::cal_vdr_precalc(const int nlocal,
             hamilt::BaseMatrix<double>* overlap_1 = phialpha[0]->find_matrix(iat, ibt1, dR1);
             hamilt::BaseMatrix<double>* overlap_2 = phialpha[0]->find_matrix(iat, ibt2, dR2);
             assert(overlap_1->get_col_size() == overlap_2->get_col_size());
-            ModuleBase::Vector3<int> dR = dR1 - dR2;
+            ModuleBase::Vector3<int> dR = dR2 - dR1;
             int iRx = DeePKS_domain::mapping_R(dR.x);
             int iRy = DeePKS_domain::mapping_R(dR.y);
             int iRz = DeePKS_domain::mapping_R(dR.z);