Fix&Refactor: soc force/stress error for LCAO code, refactor the force/stress code into operator (#5381)

* Refactor&Fix: soc force&stress for LCAO

* Fix: nspin2 error

* Fix: lack of switch_dmr

* Test: add coverage of force/stress for SOC, and delete useless code

* [pre-commit.ci lite] apply automatic fixes

* Fix&Refactor: error of NSPIN=2 and refactor DensityMatrix class

* Fix: reference of forces in Gamma_only cases

* [pre-commit.ci lite] apply automatic fixes

* Fix: change reference of Gamma-only case and SOC case

* Fix: nb2d default error with NSPIN=4

* Fix: delete useless code

---------

Co-authored-by: dyzheng <[email protected]>
Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>

Author: 3 people

source/Makefile.Objects

@@ -230,6 +230,7 @@ OBJS_ELECSTAT_LCAO=elecstate_lcao.o\
       elecstate_lcao_tddft.o\
       elecstate_lcao_cal_tau.o\
       density_matrix.o\
+      density_matrix_io.o\
       cal_dm_psi.o\
 
 OBJS_ESOLVER=esolver.o\
@@ -571,8 +572,6 @@ OBJS_LCAO=evolve_elec.o\
       stress_tools.o\
       edm.o\
       pulay_force_stress_center2.o\
-	  fvnl_dbeta_gamma.o\
-	  fvnl_dbeta_k.o\
 	  grid_init.o\
       spar_dh.o\
       spar_exx.o\

source/module_elecstate/CMakeLists.txt

@@ -35,6 +35,7 @@ if(ENABLE_LCAO)
       elecstate_lcao_cal_tau.cpp
       potentials/H_TDDFT_pw.cpp
       module_dm/density_matrix.cpp
+      module_dm/density_matrix_io.cpp
       module_dm/cal_dm_psi.cpp
   )
 endif()