From bfde586a08bfe4edc3233357797efca06f210e46 Mon Sep 17 00:00:00 2001
From: Stardust0831 <169599847+Stardust0831@users.noreply.github.com>
Date: Wed, 19 Aug 2026 02:17:31 +0800
Subject: [PATCH] fix(input): constrain diag_subspace availability

---
 docs/advanced/input_files/input-main.md               | 1 +
 docs/parameters.yaml                                  | 2 +-
 source/source_io/module_parameter/read_inp_sys.cpp    | 1 +
 source/source_io/test_serial/read_input_item_test.cpp | 4 ++++
 4 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/docs/advanced/input_files/input-main.md b/docs/advanced/input_files/input-main.md
index 422fcd3835..a03b3c4e51 100644
--- a/docs/advanced/input_files/input-main.md
+++ b/docs/advanced/input_files/input-main.md
@@ -1006,6 +1006,7 @@
 ### diag_subspace
 
 - **Type**: Integer
+- **Availability**: *[`basis_type`](#basis_type)==pw and [`ks_solver`](#ks_solver)==dav_subspace*
 - **Description**: The method to diagonalize subspace in dav_subspace method.
   - 0: by LAPACK
   - 1: by GenELPA
diff --git a/docs/parameters.yaml b/docs/parameters.yaml
index ef311d26fc..78b5997b84 100644
--- a/docs/parameters.yaml
+++ b/docs/parameters.yaml
@@ -428,7 +428,7 @@ parameters:
       * 2: by ScaLAPACK
     default_value: "0"
     unit: ""
-    availability: ""
+    availability: basis_type==pw and ks_solver==dav_subspace
   - name: erf_ecut
     category: Plane wave related variables
     type: Real
diff --git a/source/source_io/module_parameter/read_inp_sys.cpp b/source/source_io/module_parameter/read_inp_sys.cpp
index 015314956e..1d207658e4 100644
--- a/source/source_io/module_parameter/read_inp_sys.cpp
+++ b/source/source_io/module_parameter/read_inp_sys.cpp
@@ -1178,6 +1178,7 @@ Available options are:
 * 1: by GenELPA
 * 2: by ScaLAPACK)";
         item.default_value = "0";
+        item.set_availability("basis_type==pw and ks_solver==dav_subspace");
         read_sync_int(input.diag_subspace);
         this->add_item(item);
     }
diff --git a/source/source_io/test_serial/read_input_item_test.cpp b/source/source_io/test_serial/read_input_item_test.cpp
index cb86a5d2d8..93a01ae4f5 100644
--- a/source/source_io/test_serial/read_input_item_test.cpp
+++ b/source/source_io/test_serial/read_input_item_test.cpp
@@ -1990,6 +1990,10 @@ TEST_F(InputTest, Item_test2)
         output = testing::internal::GetCapturedStdout();
         EXPECT_THAT(output, testing::HasSubstr("NOTICE"));
     }
+    { // diag_subspace
+        auto it = find_label("diag_subspace", readinput.input_lists);
+        EXPECT_EQ(it->second.get_availability(), "basis_type==pw and ks_solver==dav_subspace");
+    }
     { // md_nstep
         auto it = find_label("md_nstep", readinput.input_lists);
         param.input.mdp.md_nstep = 0;