Fix: nb2d default error with NSPIN=4

Author: dyzheng

source/module_hamilt_lcao/hamilt_lcaodft/LCAO_init_basis.cpp

@@ -79,7 +79,9 @@ void init_basis_lcao(Parallel_Orbitals& pv,
     try_nb += pv.set_nloc_wfc_Eij(PARAM.inp.nbands, GlobalV::ofs_running, GlobalV::ofs_warning);
     if (try_nb != 0)
     {
-        pv.set(nlocal, nlocal, 1, pv.blacs_ctxt);
+        // fall back to the minimum size, 1 or 2 (nspin=4)
+        const int min_size = (PARAM.inp.nspin == 4) ? 2 : 1;
+        pv.set(nlocal, nlocal, min_size, pv.blacs_ctxt);
         try_nb = pv.set_nloc_wfc_Eij(PARAM.inp.nbands, GlobalV::ofs_running, GlobalV::ofs_warning);
     }
 

source/module_hamilt_lcao/hamilt_lcaodft/operator_lcao/nonlocal_force_stress.hpp

@@ -32,7 +32,7 @@ void NonlocalNew<OperatorLCAO<TK, TR>>::cal_force_stress(const bool cal_force,
     { 
         // skip the atoms without plus-U
         auto tau0 = ucell->get_tau(iat0);
-        int I0;
+        int I0 = 0;
         ucell->iat2iait(iat0, &I0, &this->current_type);
 
         // first step: find the adjacent atoms and filter the real adjacent atoms