Revert "Update CC amplitude loading (#8)" (#9)

This reverts commit 38768ff until main FermiLib is updated to match.

Author: babbush

fermilibpluginpsi4/_psi4_conversion_functions.py

@@ -253,4 +253,8 @@ def beta_unoccupied(i):
                               alpha_unoccupied(b),
                               alpha_occupied(j)] = value / 2.
 
-    return single_amplitudes, double_amplitudes
+    # Package into InteractionOperator.
+    molecule = InteractionOperator(0.0,
+                                   single_amplitudes,
+                                   double_amplitudes)
+    return molecule

fermilibpluginpsi4/_psi4_template

@@ -225,11 +225,10 @@ if &run_ccsd:
 
         # Merge CC amplitudes into molecule by parsing
         psi_filename = outfile_name()
-        single_amplitudes, double_amplitudes = parse_psi4_ccsd_amplitudes(
+        ccsd_amplitudes = parse_psi4_ccsd_amplitudes(
             2 * molecule.n_orbitals,
             molecule.get_n_alpha_electrons(),
             molecule.get_n_beta_electrons(),
             psi_filename)
-        molecule.ccsd_single_amps = single_amplitudes
-        molecule.ccsd_double_amps = double_amplitudes
+        molecule.ccsd_amplitudes = ccsd_amplitudes
         molecule.save()