refactor(esolver): extract init_esolver factory from base class file

The factory functions init_esolver() and determine_type() were previously
hosted in esolver.cpp, which is nominally the implementation file of the
abstract base class ESolver. To instantiate the concrete derived classes
(ESolver_KS_PW, ESolver_KS_LCAO, ESolver_OF, etc.), esolver.cpp had to
#include 13 derived-class headers, making the base-class file reverse-
depend on all its derivatives. This violates ABACUS coding rule 3
("Keep header dependencies minimal") and the dependency-inversion
principle.

Fix by moving the factory code into a dedicated esolver_factory module
so that esolver.h/cpp only carries the ESolver interface and knows
nothing about derived classes. The factory is the single place allowed
to see both the interface and all concrete implementations, which is
its essential responsibility.

Changes:
- Add source/source_esolver/esolver_factory.h with declarations of
  determine_type() and init_esolver(); forward-declares Input_para
  and ESolver to keep includes minimal.
- Add source/source_esolver/esolver_factory.cpp containing the full
  bodies of determine_type() and init_esolver() moved verbatim from
  esolver.cpp, plus the 13 derived-class includes that now live here.
- Remove source/source_esolver/esolver.cpp (its entire content was the
  factory code; the ESolver base class has no out-of-line members).
- Trim source/source_esolver/esolver.h: drop determine_type() and
  init_esolver() declarations and their doxygen blocks. The Input_para
  forward declaration is retained because before_all_runners() takes it
  as a parameter.
- Update source/source_esolver/CMakeLists.txt and source/Makefile.Objects
  to compile esolver_factory.cpp instead of esolver.cpp.
- Add explicit #include "source_esolver/esolver_factory.h" in
  source/source_main/driver_run.cpp, the sole caller of init_esolver();
  previously the declaration was pulled in transitively via relax_driver.h.

No runtime behavior change. After this refactor, touching a derived
esolver header no longer forces recompilation of the base-class file.

Verified: incremental build of `esolver` and `abacus_std_para` targets
in build_std_para (ENABLE_LCAO=ON) passes.

Author: abacus_fixer

source/Makefile.Objects

@@ -270,7 +270,7 @@ OBJS_ELECSTAT_LCAO=elecstate_lcao.o\
       cal_dm_psi.o\
       cal_edm_tddft.o\
 
-OBJS_ESOLVER=esolver.o\
+OBJS_ESOLVER=esolver_factory.o\
     esolver_ks.o\
     esolver_fp.o\
     esolver_ks_pw.o\

source/source_esolver/CMakeLists.txt

@@ -1,5 +1,5 @@
 list(APPEND objects
-    esolver.cpp
+    esolver_factory.cpp
     esolver_ks.cpp
     esolver_fp.cpp
     esolver_ks_pw.cpp

source/source_esolver/esolver.h

@@ -51,25 +51,6 @@ class ESolver
     std::string classname;
 };
 
-/**
- * @brief A subrutine called in init_esolver()
- *        This function returns type of ESolver
- *        Based on PARAM.inp.basis_type and PARAM.inp.esolver_type
- * @return [out] std::string The type of ESolver
- */
-std::string determine_type();
-
-/**
- * @brief Determine and initialize an ESolver based on input information.
- *
- * This function determines the type of ESolver to create based on input information and initializes
- * the corresponding ESolver child class. It supports various ESolver types including ksdft_pw,
- * ksdft_lcao, ksdft_lcao_tddft, sdft_pw, ofdft, lj_pot, and dp_pot.
- *
- * @return [out] A pointer to an ESolver object that will be initialized.
- */
-ESolver* init_esolver(const Input_para& inp);
-
 } // namespace ModuleESolver
 
 #endif

source/source_esolver/esolver.cpp source/source_esolver/esolver_factory.cppsource/source_esolver/esolver.cpp renamed to source/source_esolver/esolver_factory.cpp

@@ -1,5 +1,6 @@
-#include "esolver.h"
+#include "esolver_factory.h"
 
+#include "esolver.h"
 #include "esolver_ks_pw.h"
 #include "esolver_sdft_pw.h"
 #include "source_base/module_device/device.h"

source/source_esolver/esolver_factory.h

@@ -0,0 +1,38 @@
+#ifndef ESOLVER_FACTORY_H
+#define ESOLVER_FACTORY_H
+
+#include <string>
+
+struct Input_para;
+
+namespace ModuleESolver
+{
+
+class ESolver;
+
+/**
+ * @brief Determine the ESolver type string from input parameters.
+ *
+ * The type is decided based on PARAM.inp.basis_type and PARAM.inp.esolver_type,
+ * together with device/precision hints written to the running log.
+ *
+ * @return [out] std::string The type label consumed by init_esolver().
+ */
+std::string determine_type();
+
+/**
+ * @brief Determine and initialize an ESolver based on input information.
+ *
+ * This function determines the type of ESolver to create based on input
+ * information and initializes the corresponding ESolver child class. It
+ * supports various ESolver types including ksdft_pw, ksdft_lcao,
+ * ksdft_lcao_tddft, sdft_pw, ofdft, lj_pot, and dp_pot.
+ *
+ * @param [in] inp  Input parameters used to select and configure the ESolver.
+ * @return [out]    A pointer to the newly created ESolver object.
+ */
+ESolver* init_esolver(const Input_para& inp);
+
+} // namespace ModuleESolver
+
+#endif

source/source_main/driver_run.cpp

@@ -2,6 +2,7 @@
 #include "source_cell/check_atomic_stru.h"
 #include "source_cell/module_neighbor/sltk_atom_arrange.h"
 #include "source_relax/relax_driver.h"
+#include "source_esolver/esolver_factory.h"
 #include "source_io/module_parameter/parameter.h"
 #include "source_io/module_json/para_json.h"
 #include "source_io/module_output/print_info.h"