fix INPUT problem

Author: Fei Yang

docs/advanced/input_files/input-main.md

@@ -1468,13 +1468,15 @@ These variables are used to control the geometry relaxation.
   the first element:
   - cg: using the conjugate gradient (CG) algorithm. Note that there are two implementations of the conjugate gradient (CG) method, see [relax_new](#relax_new).
   - bfgs : using the Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm.
+  - lbfgs: using the Limited-memory Broyden–Fletcher–Goldfarb–Shanno (LBFGS) algorithm.
   - cg_bfgs: using the CG method for the initial steps, and switching to BFGS method when the force convergence is smaller than [relax_cg_thr](#relax_cg_thr).
   - sd: using the steepest descent (SD) algorithm.
   - fire: the Fast Inertial Relaxation Engine method (FIRE), a kind of molecular-dynamics-based relaxation algorithm, is implemented in the molecular dynamics (MD) module. The algorithm can be used by setting [calculation](#calculation) to `md` and [md_type](#md_type) to `fire`. Also ionic velocities should be set in this case. See [fire](../md.md#fire) for more details.
 
   the second element:
-  when the first element is bfgs,  if the second parameter is 1, it indicates the use of the new BFGS algorithm; if the second parameter is not 1, it indicates the use of the old BFGS algorithm.
+  when the first element is bfgs, if the second parameter is 1, it indicates the use of the new BFGS algorithm; if the second parameter is not 1, it indicates the use of the old BFGS algorithm.
 - **Default**: cg 1
+- **Note**:In the 3.10-LTS version, the type of this parameter is std::string. It can be set to "cg","bfgs","cg_bfgs","bfgs_trad","lbfgs","sd","fire".
 
 ### relax_new