add warning_quit in pw basis for PDOS calculations, add doscs for ploting Fermi surface in LCAO basis, add Fermi surface plot function in PW basis when out_dos=3

Author: mohanchen

docs/advanced/input_files/input-main.md

@@ -1705,7 +1705,8 @@ These variables are used to control the output of properties.
 - **Description**: Whether to output the density of states (DOS). For more information, refer to the [dos.md](../elec_properties/dos.md).
   - 0: no output
   - 1: output the density of states (DOS)
-  - 2: (lcao-only) output the density of states (DOS) and the projected density of states (PDOS)
+  - 2: (LCAO) output the density of states (DOS) and the projected density of states (PDOS)
+  - 3: output the Fermi surface file (fermi.bxsf) in BXSF format that can be visualized by XCrySDen 
 - **Default**: 0
 
 ### out_ldos

source/module_io/nscf_fermi_surf.cpp

@@ -15,8 +15,8 @@ void ModuleIO::nscf_fermi_surface(const std::string &out_band_dir,
 	ModuleBase::timer::tick("ModuleIO", "nscf_fermi_surface");
 #ifdef __MPI
 
-	int start = 1;
-	int end = PARAM.inp.nbands;
+	const int start = 1;
+	const int end = PARAM.inp.nbands;
 
 	std::ofstream ofs;
 	if(GlobalV::MY_RANK==0)

source/module_io/write_dos_pw.cpp

@@ -58,5 +58,21 @@ void ModuleIO::write_dos_pw(const ModuleBase::matrix& ekb,
 				wg);
 	}
 
+
+    if (PARAM.inp.out_dos == 2)
+    {
+        WARNING_QUIT("ModuleIO::write_dos_pw","PW basis do not support PDOS calculations yet.");
+    }
+
+    if(PARAM.inp.out_dos == 3)
+    {
+        for (int is = 0; is < nspin0; is++)
+        {
+            std::stringstream ss3;
+            ss3 << PARAM.globalv.global_out_dir << "fermi" << is << ".bxsf";
+            nscf_fermi_surface(ss3.str(), nbands, energy_fermi.ef, kv, ucell, ekb);
+        }
+    }
+
     ofs_running << " DOS CALCULATIONS ENDS." << std::endl; 
 }