cirq.kron_with_controls¶

cirq.kron_with_controls(*matrices) → numpy.ndarray[source]¶

Computes the kronecker product of a sequence of matrices and controls.

Use linalg.CONTROL_TAG to represent controls. Any entry of the output
matrix corresponding to a situation where the control is not satisfied
will
be overwritten by identity matrix elements.

The control logic works by imbuing NaN with the meaning “failed to
meet one
or more controls”. The normal kronecker product then spreads the
per-item
NaNs to all the entries in the product that need to be replaced by
identity
matrix elements. This method rewrites those NaNs. Thus CONTROL_TAG
can be
the matrix [[NaN, 0], [0, 1]] or equivalently [[NaN, NaN], [NaN, 1]].

Because this method re-interprets NaNs as control-failed elements, it
won’t
propagate error-indicating NaNs from its input to its output in the
way
you’d otherwise expect.

Parameters:	*matrices – The matrices and controls to combine with the kronecker product.
Returns:	The resulting matrix.