Docs: update BPCG solver guidance (#7701)

Author: lanshuyue

docs/advanced/input_files/input-main.md

@@ -1152,9 +1152,9 @@
   For plane-wave basis,
 
   - cg: The conjugate-gradient (CG) method.
-  - bpcg: The BPCG method, which is a block-parallel Conjugate Gradient (CG) method, typically exhibits higher acceleration in a GPU environment.
   - dav: The Davidson algorithm.
   - dav_subspace: The Davidson algorithm without orthogonalization operation, this method is the most recommended for efficiency. `pw_diag_ndim` can be set to 2 for this method.
+  - bpcg: The BPCG method, which is a block-parallel Conjugate Gradient (CG) method, typically exhibits higher acceleration in a GPU environment. The BPCG method is currently under testing and is not recommended for use.
 
   For numerical atomic orbitals basis,
 

docs/parameters.yaml

@@ -533,9 +533,9 @@ parameters:
       For plane-wave basis,
 
       * cg: The conjugate-gradient (CG) method.
-      * bpcg: The BPCG method, which is a block-parallel Conjugate Gradient (CG) method, typically exhibits higher acceleration in a GPU environment.
       * dav: The Davidson algorithm.
       * dav_subspace: The Davidson algorithm without orthogonalization operation, this method is the most recommended for efficiency. `pw_diag_ndim` can be set to 2 for this method.
+      * bpcg: The BPCG method, which is a block-parallel Conjugate Gradient (CG) method, typically exhibits higher acceleration in a GPU environment. The BPCG method is currently under testing and is not recommended for use.
 
       For numerical atomic orbitals basis,
 

source/source_io/module_parameter/read_input_item_elec_stru.cpp

@@ -53,9 +53,9 @@ void ReadInput::item_elec_stru()
 For plane-wave basis,
 
 * cg: The conjugate-gradient (CG) method.
-* bpcg: The BPCG method, which is a block-parallel Conjugate Gradient (CG) method, typically exhibits higher acceleration in a GPU environment.
 * dav: The Davidson algorithm.
 * dav_subspace: The Davidson algorithm without orthogonalization operation, this method is the most recommended for efficiency. `pw_diag_ndim` can be set to 2 for this method.
+* bpcg: The BPCG method, which is a block-parallel Conjugate Gradient (CG) method, typically exhibits higher acceleration in a GPU environment. The BPCG method is currently under testing and is not recommended for use.
 
 For numerical atomic orbitals basis,