increase default values for lambbda_q and lambda_z

Author: brucefan1983

doc/nep/input_parameters/lambda_q.rst

@@ -10,6 +10,6 @@ The syntax is::
 
   lambda_q <weight>
 
-Here, :attr:`<weight>` represents :math:`\lambda_q`, which must satisfy :math:`\lambda_q \geq 0` and defaults to :math:`\lambda_f = 0.1`.
+Here, :attr:`<weight>` represents :math:`\lambda_q`, which must satisfy :math:`\lambda_q \geq 0` and defaults to :math:`\lambda_q = 0.5`.
 
 This keyword is only relevant for the qNEP models.

doc/nep/input_parameters/lambda_z.rst

@@ -10,6 +10,6 @@ The syntax is::
 
   lambda_z <weight>
 
-Here, :attr:`<weight>` represents :math:`\lambda_z`, which must satisfy :math:`\lambda_z \geq 0` and defaults to :math:`\lambda_z = 0.1`.
+Here, :attr:`<weight>` represents :math:`\lambda_z`, which must satisfy :math:`\lambda_z \geq 0` and defaults to :math:`\lambda_z = 0.5`.
 
 This keyword is only relevant for the qNEP models.

src/main_nep/parameters.cu

@@ -91,8 +91,8 @@ void Parameters::set_default_parameters()
   lambda_e = lambda_f = 1.0f;  // energy and force are more important
   lambda_v = 0.1f;             // virial is less important
   lambda_shear = 1.0f;         // do not weight shear virial more by default
-  lambda_q = 0.1f;             // need to test
-  lambda_z = 0.1f;             // need to test
+  lambda_q = 0.5f;             // close to optimal
+  lambda_z = 0.5f;             // close to optimal
   force_delta = 0.0f;          // no modification of force loss
   batch_size = 1000;           // large enough in most cases
   use_full_batch = 0;          // default is not to enable effective full-batch