def zero_transform(string0: int, unocc: int, occ: int, norb: int) -> bool:
"""Given a bitstring, determine if it satisfies the occupation and
nonoccupation conditions necessary to be non zero when a product of creation
and annihilation operators are applied.
Args:
string0 (bitstring) - the occupation representation being acted upon
unocc (bitstring) - orbitals which should be unoccupied in string0
occ (bitstring) - orbitals which should be occupied in string0
norb (int) - the number of spatial orbitals for masking the bitstrings
Returns:
(bool) - true if the transformation is non zero, false if the
transformation is zero
"""
if check_conserved_bits(string0, occ):
if check_conserved_bits(invert_bitstring_with_mask(string0, norb),
unocc):
return False
return True
def test_check_conserved_bits_true_case(self):
"""Check for a positive conservation result
"""
conserved = 4
string0 = 1 + 4 + 8
self.assertTrue(bitstring.check_conserved_bits(string0, conserved))
def test_check_conserved_bits_false_case(self):
"""Check for a negative conservation result
"""
conserved = 2
string0 = 1 + 4 + 8
self.assertFalse(bitstring.check_conserved_bits(string0, conserved))
def test_check_conserved_bits_none(self):
"""Make sure that no bits are still conserved bits
"""
self.assertTrue(bitstring.check_conserved_bits(0, 0))