Update pymodule.py (#425)

* Update pymodule.py

* Update df-casscf-gradient-2

* Update df-casscf-gradient-2 output.ref

Author: lcyyork

forte/pymodule.py

@@ -311,7 +311,7 @@ def gradient_forte(name, **kwargs):
     derivobj = psi4.core.Deriv(data.psi_wfn)
     derivobj.set_deriv_density_backtransformed(True)
     derivobj.set_ignore_reference(True)
-    if int_type == "DF":
+    if "DF" in int_type:
         grad = derivobj.compute_df("DF_BASIS_SCF", "DF_BASIS_MP2")
     else:
         grad = derivobj.compute(psi4.core.DerivCalcType.Correlated)

tests/methods/df-casscf-gradient-2/input.dat

@@ -58,5 +58,9 @@ set forte{
 
 #set gradient_write true
 #set findif points 5
-grad = gradient('forte')
-compare_matrices(ref_grad, grad, 7, "CASSCF(4,4)/DZ gradient on butadiene with frozen orbitals")
+grad1 = gradient('forte')
+compare_matrices(ref_grad, grad1, 7, "CASSCF(4,4)/DZ gradient on butadiene with frozen orbitals")
+
+set forte int_type diskdf
+grad2 = gradient('forte')
+compare_matrices(grad1, grad2, 8, "DISKDF vs DF CASSCF(4,4)/DZ gradient")