modification of functions that need psi4

quantnbody/fermionic/tools.py

@@ -4,7 +4,6 @@
 from itertools import combinations
 from numba import njit, prange
 import matplotlib.pyplot as plt
-import psi4
 
 E_ = False
 e_ = False
@@ -1650,6 +1649,16 @@ def get_info_from_psi4( string_geometry,
         Energy of the nuclei repulsion
 
     """
+
+    try:
+        import psi4
+    except ImportError as exc:
+        raise RuntimeError(
+            "psi4 is not installed. This function need psi4 to work."
+            "Install it before using get_info_from_psi4"
+        ) from exc
+
+
     if not TELL_ME:
         # To prevent psi4 from printing the output in the terminal
         psi4.core.set_output_file("output_Psi4.txt", False)

quantnbody/fermionic_fockspace/tools.py

@@ -3,7 +3,6 @@
 import numpy as np
 from itertools import combinations
 from numba import njit, prange
-import psi4
 
 E_ = False
 e_ = False
@@ -1340,6 +1339,17 @@ def get_info_from_psi4( string_geometry,
         Energy of the nuclei repulsion
 
     """
+
+    try:
+        import psi4
+    except ImportError as exc:
+        raise RuntimeError(
+            "psi4 is not installed. This function need psi4 to work. "
+            "Install it before using get_info_from_psi4"
+        ) from exc
+
+
+
     if not TELL_ME:
         # To prevent psi4 from printing the output in the terminal
         psi4.core.set_output_file("output_Psi4.txt", False)

quantnbody/hybrid_fermionic_bosonic/tools.py

@@ -4,7 +4,6 @@
 from numba import njit, prange
 import matplotlib.pyplot as plt
 import scipy.sparse
-import psi4
 
 
 # =============================================================================
@@ -717,6 +716,16 @@ def cqed_rhf(lambda_vector, molecule_string, psi4_options_dict):
     >>> cqed_rhf_dictionary = cqed_rhf([0., 0., 1e-2], '''\nMg\nH 1 1.7\nsymmetry c1\n1 1\n''', psi4_options_dictionary)
 
     """
+    try:
+        import psi4
+    except ImportError as exc:
+        raise RuntimeError(
+            "psi4 is not installed. This function need psi4 to work."
+            "Install it before using cqed_rhf"
+        ) from exc
+
+
+
     # define geometry using the molecule_string
     mol = psi4.geometry(molecule_string)
     # define options for the calculation
@@ -1813,4 +1822,4 @@ def binom(n, k):
     for i in range(1, k+1):
         numerator *= (n - (k - i))
         denominator *= i
-    return numerator // denominator
+    return numerator // denominator

testing/TESTS.py

@@ -1,11 +1,17 @@
 import unittest
 import numpy as np
-import psi4
 import scipy
 import quantnbody as qnb
 
+def _psi4_is_available():
+    try:
+        import psi4          
+        return True
+    except ImportError:
+        return False
 
 class MyTestCase(unittest.TestCase):
+
     def test_FERMION_BASICS(self):
         # ========================================================|
         # Parameters for the simulation
@@ -89,6 +95,9 @@ def test_FERMION_MODEL_HAMILTONIAN(self):
 
     def test_FERMION_AB_INITIO_HAMILTONIAN(self):
 
+        if not _psi4_is_available():
+            self.skipTest("psi4 not installed, test skipped")
+
         psi4.core.set_output_file("output_Psi4.txt", False)
         basisset = 'sto-3g'
         nelec_active = 2  # Number of active electrons in the Active-Space