fix(input): reject PW gamma_only without rewriting KPT

examples/21_deepks/01_pw_H2O/INPUT

@@ -14,7 +14,7 @@ scf_nmax             50
 
 #Parameters (3.Basis)
 basis_type           pw
-gamma_only           1 ### Abacus will generate/overwrite a KPT file when gamma_only is set to 1.
+gamma_only           0 # Gamma-point sampling is specified in KPT.
 
 #Parameters (4.Smearing)
 smearing_method      gaussian

examples/21_deepks/01_pw_H2O/KPT

@@ -2,4 +2,3 @@ K_POINTS
 0
 Gamma
 1 1 1 0 0 0
-###This file will be overwritten by Abacus because either kspacing is used or gamma_only is set to 1

examples/27_imp_sol/01_pw_Pt_slab/INPUT

@@ -8,7 +8,7 @@ ecutwfc              60 ###Energy cutoff needs to be tested to ensure your calcu
 scf_nmax             200
 scf_thr              1.0e-7
 basis_type           pw
-gamma_only           1 ### Abacus will generate/overwrite a KPT file when gamma_only is set to 1.
+gamma_only           0 # Gamma-point sampling is specified in KPT.
 smearing_method      gauss
 smearing_sigma       0.015
 mixing_type          broyden

examples/27_imp_sol/01_pw_Pt_slab/KPT

@@ -0,0 +1,4 @@
+K_POINTS
+0
+Gamma
+1 1 1 0 0 0

examples/28_efield/01_Pt_slab/INPUT

@@ -8,7 +8,7 @@ ecutwfc              60 ###Energy cutoff needs to be tested to ensure your calcu
 scf_nmax             200
 scf_thr              1.0e-7
 basis_type           pw
-gamma_only           1 ### Abacus will generate/overwrite a KPT file when gamma_only is set to 1.
+gamma_only           0 # Gamma-point sampling is specified in KPT.
 smearing_method      gauss
 smearing_sigma       0.015
 mixing_type          broyden

examples/28_efield/01_Pt_slab/KPT

@@ -0,0 +1,4 @@
+K_POINTS
+0
+Gamma
+1 1 1 0 0 0

examples/29_dipole_corr/01_Pt_slab/INPUT1

@@ -8,7 +8,7 @@ ecutwfc		  60
 scf_nmax	  200
 scf_thr		  1.0e-7
 basis_type	  pw
-gamma_only        1
+gamma_only        0 # Gamma-point sampling is specified in KPT.
 smearing_method	  gauss
 smearing_sigma	  0.02
 mixing_type       broyden

examples/29_dipole_corr/01_Pt_slab/INPUT2

@@ -8,7 +8,7 @@ ecutwfc		  60
 scf_nmax	  200
 scf_thr		  1.0e-7
 basis_type	  pw
-gamma_only        1
+gamma_only        0 # Gamma-point sampling is specified in KPT.
 smearing_method	  gauss
 smearing_sigma	  0.02
 mixing_type       broyden

examples/29_dipole_corr/01_Pt_slab/KPT

@@ -0,0 +1,4 @@
+K_POINTS
+0
+Gamma
+1 1 1 0 0 0

examples/31_comp_charge/01_Pt_slab/INPUT

@@ -8,7 +8,7 @@ ecutwfc              60 ###Energy cutoff needs to be tested to ensure your calcu
 scf_nmax             200
 scf_thr              1.0e-7
 basis_type           pw
-gamma_only           1 ### Abacus will generate/overwrite a KPT file when gamma_only is set to 1.
+gamma_only           0 # Gamma-point sampling is specified in KPT.
 smearing_method      gauss
 smearing_sigma       0.015
 mixing_type          broyden

examples/31_comp_charge/01_Pt_slab/KPT

@@ -0,0 +1,4 @@
+K_POINTS
+0
+Gamma
+1 1 1 0 0 0

source/source_io/module_parameter/read_inp_estruc.cpp

@@ -793,30 +793,24 @@ This setting takes effect only when the selected exchange-correlation functional
                           "set to 1, a fast algorithm is used";
         item.category = "Electronic structure";
         item.type = "Boolean";
-        item.description = R"(Whether to use gamma_only algorithm.
-* 0: more than one k-point is used and the ABACUS is slower compared to the gamma only algorithm.
-* 1: ABACUS uses gamma only, the algorithm is faster and you don't need to specify the k-points file.
+        item.description = R"(Whether to use the optimized Gamma-only algorithm.
+* 0: use the general k-point algorithm, including for a single Gamma point.
+* 1: use the optimized algorithm for localized orbitals with nspin=1 or 2; no KPT file is needed.
 
-Note: If gamma_only is set to 1, the KPT file will be overwritten. So make sure to turn off gamma_only for multi-k calculations.)";
+PW calculations require gamma_only=0. For Gamma-point sampling in PW, specify a 1 1 1 0 0 0 Gamma mesh in KPT. An explicit gamma_only=1 with basis_type=pw is an input error; the input reader does not create or overwrite KPT.)";
         item.default_value = "0";
         item.unit = "";
         item.set_availability("basis_type==lcao");
         read_sync_bool(input.gamma_only);
-        item.reset_value = [](const Input_Item& item, Parameter& para) {
+        item.check_value = [](const Input_Item& item, const Parameter& para) {
             if (para.input.basis_type == "pw" && para.input.gamma_only)
             {
-                para.input.gamma_only = false;
-                GlobalV::ofs_warning << " WARNING : gamma_only has not been implemented for pw yet" << std::endl;
-                GlobalV::ofs_warning << "gamma_only is not supported in the pw model" << std::endl;
-                GlobalV::ofs_warning << " the INPUT parameter gamma_only has been reset to 0" << std::endl;
-                GlobalV::ofs_warning << " and a new KPT is generated with gamma point as the only k point"<< std::endl;
-                GlobalV::ofs_warning << " Auto generating k-points file: " << para.input.kpoint_file << std::endl;
-                std::ofstream ofs(para.input.kpoint_file.c_str());
-                ofs << "K_POINTS" << std::endl;
-                ofs << "0" << std::endl;
-                ofs << "Gamma" << std::endl;
-                ofs << "1 1 1 0 0 0" << std::endl;
-                ofs.close();
+                const std::string message
+                    = "Invalid INPUT gamma_only=" + longstring(item.str_values)
+                      + " with basis_type=pw. PW requires gamma_only=0; for Gamma-point sampling, "
+                        "use a 1 1 1 0 0 0 Gamma mesh in KPT. KPT is not modified.\n"
+                        "See https://abacus.deepmodeling.com/en/latest/advanced/input_files/input-main.html#gamma-only";
+                ModuleBase::WARNING_QUIT("ReadInput", message);
             }
             if (para.input.basis_type == "lcao" && para.input.gamma_only)
             {

source/source_io/test_serial/read_input_item_test.cpp

@@ -1145,20 +1145,18 @@ TEST_F(InputTest, Item_test)
         auto it = find_label("gamma_only", readinput.input_lists);
         TestParameters::input(param).basis_type = "pw";
         TestParameters::input(param).gamma_only = true;
-        std::string filename = TestParameters::input(param).kpoint_file;
-        it->second.reset_value(it->second, param);
-        EXPECT_EQ(TestParameters::input(param).gamma_only, false);
-        std::ifstream ifs(filename);
-        std::string line;
-        std::getline(ifs, line);
-        ifs.close();
-        EXPECT_EQ(line, "K_POINTS");
+        it->second.str_values = {"1"};
+        EXPECT_EXIT(it->second.check_value(it->second, param), ::testing::ExitedWithCode(1), "");
+        EXPECT_TRUE(TestParameters::input(param).gamma_only);
+
+        TestParameters::input(param).gamma_only = false;
+        EXPECT_NO_THROW(it->second.check_value(it->second, param));
 
         TestParameters::input(param).basis_type = "lcao";
         TestParameters::input(param).gamma_only = true;
         TestParameters::input(param).nspin = 4;
         testing::internal::CaptureStdout();
-        EXPECT_EXIT(it->second.reset_value(it->second, param), ::testing::ExitedWithCode(1), "");
+        EXPECT_EXIT(it->second.check_value(it->second, param), ::testing::ExitedWithCode(1), "");
         output = testing::internal::GetCapturedStdout();
         EXPECT_THAT(output, testing::HasSubstr("NOTICE"));
 
@@ -1271,6 +1269,71 @@ TEST_F(InputTest, Item_test)
     }
 }
 
+TEST_F(InputTest, RejectPwGammaOnlyWithoutChangingKpt)
+{
+    const std::string filename = testing::TempDir() + "abacus_pw_gamma_INPUT";
+    const std::string kpt = testing::TempDir() + "abacus_pw_gamma_KPT";
+    const std::string content = "K_POINTS\n0\nGamma\n2 3 4 0 0 0\n";
+    for (const bool existing_kpt : {false, true})
+    {
+        SCOPED_TRACE(existing_kpt);
+        if (existing_kpt)
+        {
+            std::ofstream output(kpt.c_str());
+            output << content;
+        }
+        {
+            std::ofstream input(filename.c_str());
+            input << "INPUT_PARAMETERS\nbasis_type pw\ngamma_only 1\nkpoint_file " << kpt << "\n";
+        }
+        ModuleIO::ReadInput reader(0);
+        reader.check_ntype_flag = false;
+        Parameter param;
+        testing::internal::CaptureStdout();
+        EXPECT_EXIT(reader.read_parameters(param, filename), testing::ExitedWithCode(1), "");
+        const std::string diagnostic = testing::internal::GetCapturedStdout();
+        EXPECT_THAT(diagnostic, testing::HasSubstr("Invalid INPUT gamma_only=1"));
+        EXPECT_THAT(diagnostic, testing::HasSubstr("PW requires gamma_only=0"));
+        EXPECT_THAT(diagnostic, testing::HasSubstr("1 1 1 0 0 0 Gamma mesh"));
+        EXPECT_THAT(diagnostic, testing::HasSubstr("input-main.html#gamma-only"));
+        std::ifstream actual(kpt.c_str());
+        if (existing_kpt)
+        {
+            std::stringstream buffer;
+            buffer << actual.rdbuf();
+            EXPECT_EQ(buffer.str(), content);
+            actual.close();
+            EXPECT_EQ(std::remove(kpt.c_str()), 0);
+        }
+        else
+        {
+            EXPECT_FALSE(actual.is_open());
+        }
+        EXPECT_EQ(std::remove(filename.c_str()), 0);
+    }
+}
+
+TEST_F(InputTest, AcceptSupportedGammaOnlyInputs)
+{
+    const std::string filename = testing::TempDir() + "abacus_supported_gamma_INPUT";
+    for (const std::string parameters : {"basis_type pw\ngamma_only 0\n",
+                                         "basis_type lcao\ngamma_only 1\nnspin 1\n",
+                                         "basis_type lcao\ngamma_only 1\nnspin 2\n"})
+    {
+        SCOPED_TRACE(parameters);
+        {
+            std::ofstream input(filename.c_str());
+            input << "INPUT_PARAMETERS\n" << parameters;
+        }
+        ModuleIO::ReadInput reader(0);
+        reader.check_ntype_flag = false;
+        Parameter param;
+        reader.read_parameters(param, filename);
+        EXPECT_EQ(param.inp.gamma_only, param.inp.basis_type == "lcao");
+        EXPECT_EQ(std::remove(filename.c_str()), 0);
+    }
+}
+
 TEST_F(InputTest, HsOutputAliases)
 {
     {

tests/01_PW/027_PW_PINT_RKS/INPUT

@@ -10,7 +10,7 @@ ecutwfc           50
 scf_nmax          20
 
 basis_type        pw
-gamma_only        1
+gamma_only        0 # Gamma-point sampling is specified in KPT.
 
 init_wfc          nao
 

tests/01_PW/028_PW_PINT_UKS/INPUT

@@ -16,7 +16,7 @@ mixing_beta_mag   0.4
 
 ks_solver         cg
 basis_type        pw
-gamma_only        1
+gamma_only        0 # Gamma-point sampling is specified in KPT.
 nspin             2
 pseudo_dir        ../../../tests/PP_ORB
 orbital_dir       ../../../tests/PP_ORB

tests/09_DeePKS/97_PW_ORB_deepks_s/INPUT

@@ -14,7 +14,7 @@ scf_nmax          50
 
 #Parameters (3.Basis)
 basis_type        pw
-gamma_only        1
+gamma_only        0 # Gamma-point sampling is specified in KPT.
 
 #Parameters (4.Smearing)
 smearing_method   gaussian

tests/09_DeePKS/98_PW_ORB_deepks_p/INPUT

@@ -14,7 +14,7 @@ scf_nmax          50
 
 #Parameters (3.Basis)
 basis_type        pw
-gamma_only        1
+gamma_only        0 # Gamma-point sampling is specified in KPT.
 
 #Parameters (4.Smearing)
 smearing_method   gaussian

tests/09_DeePKS/99_PW_ORB_deepks_d/INPUT

@@ -13,7 +13,7 @@ scf_nmax          50
 
 #Parameters (3.Basis)
 basis_type        pw
-gamma_only        1
+gamma_only        0 # Gamma-point sampling is specified in KPT.
 
 #Parameters (4.Smearing)
 smearing_method   gaussian