Merge b0fe63e into b170c4d

drudge/fock.py

@@ -1061,7 +1061,7 @@ class BogoliubovDrudge(GenMBDrudge):
 
     .. math::
 
-        \beta^\dagger_k = \sum_l u_{lk} c^\dagger_l v_{lk} c_l
+        \beta^\dagger_k = \sum_l u_{lk} c^\dagger_l + v_{lk} c_l
 
     Then the Hamiltonian is going to be rewritten with matrix elements formatted
     according to the given format.  During the rewritten, the new matrix

drudge/genquad.py

@@ -391,7 +391,7 @@ def _swap_lattice_gens(vec1: Vec, vec2: Vec, bcast_swap_info):
             comm_factor = -1 / phase
             phase = 1 / phase
         elif assume_comm:
-            comm = _NOUGHT
+            comm = parse_terms(_NOUGHT)
             phase = _UNITY
             comm_factor = _UNITY
         else:

tests/genquad_test.py

@@ -0,0 +1,26 @@
+"""Tests for the general quadratic algebra drudge"""
+
+import pytest
+from sympy import Integer
+from drudge import Vec, GenQuadLatticeDrudge
+
+
+def test_assume_comm(spark_ctx):
+    """
+    Test the case where vectors are assumed to commute if there commutator
+    is not specified.
+    """
+
+    v1 = Vec(r'v_1')
+    v2 = Vec(r'v_2')
+
+    dr = GenQuadLatticeDrudge(spark_ctx, order=(v1, v2), comms={},
+                              assume_comm=True)
+    tensor = dr.sum(v1 | v2)
+
+    assert tensor.simplify() == Integer(0)
+
+
+
+
+