Docs: Fix doc and warning for init_chg, nspin=1

docs/advanced/input_files/input-main.md

@@ -639,7 +639,7 @@ These variables are used to control general system parameters.
 - **Description**: This variable is used for both plane wave set and localized orbitals set. It indicates the type of starting density.
 
   - atomic: the density is starting from the summation of the atomic density of single atoms.
-  - file: the density will be read in from a binary file `charge-density.dat` first. If it does not exist, the charge density will be read in from cube files. Besides, when you do `nspin=1` calculation, you only need the density file chgs1.cube. However, if you do `nspin=2` calculation, you also need the density file chgs2.cube. The density file should be output with these names if you set out_chg = 1 in INPUT file.
+  - file: the density will be read in from a binary file `charge-density.dat` first. If it does not exist, the charge density will be read in from cube files. When you do `nspin=1` calculation, you only need the density file `chg.cube`. For `nspin=2 or 4` calculation, you need the density file `chgs1.cube` and `chgs2.cube` (and `chgs3.cube`, `chgs4.cube` if needed). The density file should be output with these names if you set out_chg = 1 in INPUT file.
   - wfc: the density will be calculated by wavefunctions and occupations. Wavefunctions are read in from binary files `wf*.dat` (see [out_wfc_pw](#out_wfc_pw)) while occupations are read in from file `eig.txt`.
   - dm: the density will be calculated by real space density matrix(DMR) of LCAO base. DMR is read in from file `dmrs1_nao.csr` in directory [read_file_dir](#read_file_dir).
   - hr: the real space Hamiltonian matrix(HR) will be read in from file `hrs1_nao.csr` in directory [read_file_dir](#read_file_dir), and DMR and charge density will be calculated from it.

source/source_cell/pseudo.cpp

@@ -34,7 +34,7 @@ void pseudo::check_betar()
 	}
 	if (min_flag)
 	{
-		std::cout << "WARNING: some of potential function is set to zero cause of less than 1e-30.\n";
+		std::cout << " WARNING: some of potential function is set to zero cause of less than 1e-30.\n";
 	}
 }
 

source/source_estate/module_charge/charge_init.cpp

@@ -60,14 +60,14 @@ void Charge::init_rho(const UnitCell& ucell,
         {
             for (int is = 0; is < nspin; ++is)
             {
-				std::stringstream ssc; 
+				std::stringstream ssc;
 
 				if(nspin==1)
 				{
                     ssc << PARAM.globalv.global_readin_dir << "chg.cube";
 				}
 				else
-				{               
+				{
 					ssc << PARAM.globalv.global_readin_dir << "chgs" << is + 1 << ".cube";
 				}
 
@@ -118,7 +118,7 @@ void Charge::init_rho(const UnitCell& ucell,
         {
             const std::string warn_msg
                 = " WARNING: \"init_chg\" is enabled but ABACUS failed to read\n charge density from file.\n"
-                  " Please check if there is chgsx.cube (x=1,2,etc.) or\n {suffix}-CHARGE-DENSITY.restart in the "
+                  " Please check if there is chg.cube (for nspin=1) or chgsx.cube (x=1,2,etc.) or\n {suffix}-CHARGE-DENSITY.restart in the "
                   "directory.\n";
             std::cout << warn_msg;
             if (PARAM.inp.init_chg == "file")
@@ -230,7 +230,7 @@ void Charge::init_rho(const UnitCell& ucell,
             }
             catch (const std::exception& e)
             {
-                // try to load from the output of `out_chg` 
+                // try to load from the output of `out_chg`
                 std::stringstream ssc;
                 ssc << PARAM.globalv.global_readin_dir << "chgs" << is + 1 << ".cube";
                 if (ModuleIO::read_vdata_palgrid(pgrid,
@@ -262,7 +262,7 @@ void Charge::init_rho(const UnitCell& ucell,
 
 		ModuleIO::read_wf2rho_pw(pw_wfc, symm, *this,
                 PARAM.globalv.global_readin_dir,
-				GlobalV::KPAR, GlobalV::MY_POOL, GlobalV::MY_RANK, 
+				GlobalV::KPAR, GlobalV::MY_POOL, GlobalV::MY_RANK,
                 GlobalV::NPROC_IN_POOL, GlobalV::RANK_IN_POOL,
 				PARAM.inp.nbands, nspin, PARAM.globalv.npol,
 				kv->get_nkstot(),kv->ik2iktot,kv->isk,GlobalV::ofs_running);
@@ -273,7 +273,7 @@ void Charge::init_rho(const UnitCell& ucell,
 // computes the core charge on the real space 3D mesh.
 //==========================================================
 void Charge::set_rho_core(const UnitCell& ucell,
-                          const ModuleBase::ComplexMatrix& structure_factor, 
+                          const ModuleBase::ComplexMatrix& structure_factor,
                           const bool* numeric)
 {
     ModuleBase::TITLE("Charge","set_rho_core");
@@ -300,7 +300,7 @@ void Charge::set_rho_core(const UnitCell& ucell,
     ModuleBase::GlobalFunc::ZEROS(rhocg, this->rhopw->ngg );
 
 	// three dimension.
-    std::complex<double> *vg = new std::complex<double>[this->rhopw->npw];	
+    std::complex<double> *vg = new std::complex<double>[this->rhopw->npw];
 
     for (int it = 0; it < ucell.ntype;it++)
     {
@@ -425,11 +425,11 @@ void Charge::non_linear_core_correction
 		igl_end += igl_beg;
 
         // G <> 0 term
-        for (int igl = igl_beg; igl < igl_end;igl++) 
+        for (int igl = igl_beg; igl < igl_end;igl++)
         {
             gx = sqrt(this->rhopw->gg_uniq[igl] * tpiba2);
             ModuleBase::Sphbes::Spherical_Bessel(mesh, r, gx, 0, aux);
-            for (int ir = 0;ir < mesh; ir++) 
+            for (int ir = 0;ir < mesh; ir++)
             {
                 aux [ir] = r[ir] * r[ir] * rhoc [ir] * aux [ir];
             } //  enddo
@@ -447,7 +447,7 @@ void Charge::non_linear_core_correction
 	}; // end kernel
 
 	// do not use omp parallel when this function is already in parallel block
-	// 
+	//
 	// it is called in parallel block in Forces::cal_force_cc,
 	// but not in other funtcion such as Stress_Func::stress_cc.
 	ModuleBase::TRY_OMP_PARALLEL(kernel);