refactor(cell): split unitcell.cpp into index/stats/setup files

source/Makefile.Objects

@@ -212,6 +212,9 @@ OBJS_CELL=atom_pseudo.o\
     read_pp_blps.o\
     read_pp_vwr.o\
     unitcell.o\
+    unitcell_index.o\
+    unitcell_stats.o\
+    unitcell_setup.o\
     read_atoms.o\
     read_atoms_helper.o\
     print_cell.o\

source/source_cell/CMakeLists.txt

@@ -24,6 +24,9 @@ add_library(
     mdcell_reader.cpp
     mdcell.cpp
     unitcell.cpp
+    unitcell_index.cpp
+    unitcell_stats.cpp
+    unitcell_setup.cpp
     read_atoms.cpp
     read_atoms_helper.cpp
     read_orb.cpp

source/source_cell/test/CMakeLists.txt

@@ -23,6 +23,9 @@ install(FILES bcast_sep_cell_test.sh DESTINATION ${CMAKE_CURRENT_BINARY_DIR})
 
 list(APPEND cell_simple_srcs
     ../unitcell.cpp
+    ../unitcell_index.cpp
+    ../unitcell_stats.cpp
+    ../unitcell_setup.cpp
     ../update_cell.cpp
     ../bcast_cell.cpp
     ../print_cell.cpp
@@ -138,6 +141,9 @@ AddTest(
     ../print_cell.cpp
     ../atom_spec.cpp
     ../unitcell.cpp
+    ../unitcell_index.cpp
+    ../unitcell_stats.cpp
+    ../unitcell_setup.cpp
     ../update_cell.cpp
     ../bcast_cell.cpp
     ../atom_pseudo.cpp
@@ -176,6 +182,12 @@ AddTest(
   SOURCES unitcell_test.cpp ../cal_ux.cpp
 )
 
+AddTest(
+  TARGET MODULE_CELL_unitcell_index_test
+  LIBS base device cell_info symmetry
+  SOURCES test_unitcell_index.cpp ../magnetism.cpp
+)
+
 AddTest(
   TARGET MODULE_CELL_print_cell_test
   LIBS base device cell_info symmetry

source/source_cell/test/test_unitcell_index.cpp

@@ -0,0 +1,75 @@
+#include "../unitcell.h"
+
+#include <gtest/gtest.h>
+
+class TestUnitCellIndex : public ::testing::Test
+{
+  protected:
+    void SetUp() override
+    {
+        // Build a minimal UnitCell:
+        // 2 species, 2 atoms of the first species, 1 atom of the second
+        ucell.ntype = 2;
+        ucell.nat = 3;
+        ucell.atoms = new Atom[2];
+        ucell.atoms[0].na = 2;
+        ucell.atoms[0].nw = 4; // 4 orbitals
+        ucell.atoms[1].na = 1;
+        ucell.atoms[1].nw = 2; // 2 orbitals
+        ucell.set_atom_flag = true;
+    }
+
+    void TearDown() override
+    {
+        // Do NOT delete[] ucell.atoms: ~UnitCell() frees it (set_atom_flag = true).
+        // Do NOT delete[] iat2it/iat2ia either: they are owned by the internal
+        // Statistics member, whose destructor releases them (see AGENTS.md).
+    }
+
+    UnitCell ucell;
+};
+
+TEST_F(TestUnitCellIndex, SetIat2itia)
+{
+    ucell.set_iat2itia();
+    // iat2it: [0, 0, 1]
+    EXPECT_EQ(ucell.iat2it[0], 0);
+    EXPECT_EQ(ucell.iat2it[1], 0);
+    EXPECT_EQ(ucell.iat2it[2], 1);
+    // iat2ia: [0, 1, 0]
+    EXPECT_EQ(ucell.iat2ia[0], 0);
+    EXPECT_EQ(ucell.iat2ia[1], 1);
+    EXPECT_EQ(ucell.iat2ia[2], 0);
+}
+
+TEST_F(TestUnitCellIndex, SetIat2itiaCalledTwice)
+{
+    // Cover the delete[] + new[] reallocation path: the second call must
+    // produce the same mapping as the first.
+    ucell.set_iat2itia();
+    ucell.set_iat2itia();
+    EXPECT_EQ(ucell.iat2it[0], 0);
+    EXPECT_EQ(ucell.iat2it[1], 0);
+    EXPECT_EQ(ucell.iat2it[2], 1);
+    EXPECT_EQ(ucell.iat2ia[0], 0);
+    EXPECT_EQ(ucell.iat2ia[1], 1);
+    EXPECT_EQ(ucell.iat2ia[2], 0);
+}
+
+TEST_F(TestUnitCellIndex, SetIat2iwtNpol1)
+{
+    ucell.set_iat2iwt(1);
+    // iat=0: iwt=0, iat=1: iwt=4, iat=2: iwt=8
+    EXPECT_EQ(ucell.get_iat2iwt()[0], 0);
+    EXPECT_EQ(ucell.get_iat2iwt()[1], 4);
+    EXPECT_EQ(ucell.get_iat2iwt()[2], 8);
+}
+
+TEST_F(TestUnitCellIndex, SetIat2iwtNpol2)
+{
+    ucell.set_iat2iwt(2);
+    // iat=0: iwt=0, iat=1: iwt=8, iat=2: iwt=16
+    EXPECT_EQ(ucell.get_iat2iwt()[0], 0);
+    EXPECT_EQ(ucell.get_iat2iwt()[1], 8);
+    EXPECT_EQ(ucell.get_iat2iwt()[2], 16);
+}

source/source_cell/test_pw/CMakeLists.txt

@@ -12,7 +12,7 @@ install(FILES unitcell_test_pw_para.sh DESTINATION ${CMAKE_CURRENT_BINARY_DIR})
 AddTest(
   TARGET MODULE_CELL_unitcell_test_pw
   LIBS parameter base device
-  SOURCES unitcell_test_pw.cpp ../unitcell.cpp ../read_atoms.cpp ../read_atoms_helper.cpp ../cell_tools.cpp ../atom_spec.cpp ../update_cell.cpp ../bcast_cell.cpp
+  SOURCES unitcell_test_pw.cpp ../unitcell.cpp ../unitcell_index.cpp ../unitcell_stats.cpp ../unitcell_setup.cpp ../read_atoms.cpp ../read_atoms_helper.cpp ../cell_tools.cpp ../atom_spec.cpp ../update_cell.cpp ../bcast_cell.cpp
 	../atom_pseudo.cpp ../pseudo.cpp ../read_pp.cpp ../read_pp_complete.cpp ../read_pp_upf201.cpp ../read_pp_upf100.cpp
   ../read_stru.cpp   ../read_atom_species.cpp
 	../read_pp_vwr.cpp ../read_pp_blps.cpp