Just starting local-CC design.

pycc/ccenergy.py

@@ -63,7 +63,7 @@ class ccenergy(object):
         Computes the T1 and T2 residuals for a given set of amplitudes and Fock operator
     """
 
-    def __init__(self, scf_wfn):
+    def __init__(self, scf_wfn, local):
         """
         Parameters
         ----------
@@ -84,6 +84,8 @@ def __init__(self, scf_wfn):
         self.nmo = self.ref.nmo()                       # all MOs/AOs
         self.nv = self.nmo - self.no - self.nfzc   # active virt
 
+        H = Hamiltonian(scf_wfn, local=local)
+
         # Get MOs
         C = self.ref.Ca_subset("AO", "ACTIVE")
         npC = np.asarray(C)  # as numpy array

pycc/hamiltonian.py

@@ -0,0 +1,30 @@
+if __name__ == "__main__":
+    raise Exception("This file cannot be invoked on its own.")
+
+
+import psi4
+import numpy as np
+
+class Hamiltonian(object):
+
+
+    def __init__(self, ref, local=None):
+        self.ref = ref
+
+        if (local != None):
+            C_occ = self.ref.Ca_subset("AO", "ACTIVE_OCC")
+            Local = psi4.core.Localizer.build("PIPEK_MEZEY", ref.bassiset(), C_occ)
+
+        # Get MOs
+        C = self.ref.Ca_subset("AO", "ACTIVE")
+        npC = np.asarray(C)  # as numpy array
+
+        # Get MO Fock matrix
+        self.F = np.asarray(self.ref.Fa())
+        self.F = np.einsum('uj,vi,uv', npC, npC, self.F)
+
+        # Get MO two-electron integrals in Dirac notation
+        mints = psi4.core.MintsHelper(self.ref.basisset())
+        self.ERI = np.asarray(mints.mo_eri(C, C, C, C))     # (pr|qs)
+        self.ERI = self.ERI.swapaxes(1,2)                   # <pq|rs>
+        self.L = 2.0 * self.ERI - self.ERI.swapaxes(2,3)    # 2 <pq|rs> - <pq|sr>

pycc/local.py

@@ -0,0 +1,4 @@
+class local(object):
+
+    def __init__(self, wfn):
+