def _is_cp_helper(self, choi, atol, rtol):
"""Test if a channel is completely-positive (CP)"""
if atol is None:
atol = self.atol
if rtol is None:
rtol = self.rtol
return is_positive_semidefinite_matrix(choi, rtol=rtol, atol=atol)
def _is_cp(self, choi=None):
"""Test if a channel is completely-positive (CP)"""
if choi is None:
choi = _to_choi(self.rep, self._data, *self.dim)
return is_positive_semidefinite_matrix(choi,
rtol=self._rtol,
atol=self._atol)
def is_valid(self, atol=None, rtol=None):
"""Return True if trace 1 and positive semidefinite."""
if atol is None:
atol = self.atol
if rtol is None:
rtol = self.rtol
# Check trace == 1
if not np.allclose(self.trace(), 1, rtol=rtol, atol=atol):
return False
# Check Hermitian
if not is_hermitian_matrix(self.data, rtol=rtol, atol=atol):
return False
# Check positive semidefinite
return is_positive_semidefinite_matrix(self.data, rtol=rtol, atol=atol)
def _is_cp(self):
"""Test if Choi-matrix is completely-positive (CP)"""
return is_positive_semidefinite_matrix(
self._data, rtol=self.rtol, atol=self.atol)
