def tensor(self, *others):
if len(others) != 1:
return monoidal.Diagram.tensor(self, *others)
other, = others
f = rigid.Box('f', Ty('c00', 'q00', 'q00'), Ty('c10', 'q10', 'q10'))
g = rigid.Box('g', Ty('c01', 'q01', 'q01'), Ty('c11', 'q11', 'q11'))
above = Diagram.id(f.dom[:1] @ g.dom[:1] @ f.dom[1:2])\
@ Diagram.swap(g.dom[1:2], f.dom[2:]) @ Diagram.id(g.dom[2:])\
>> Diagram.id(f.dom[:1]) @ Diagram.swap(g.dom[:1], f.dom[1:])\
@ Diagram.id(g.dom[1:])
below =\
Diagram.id(f.cod[:1]) @ Diagram.swap(f.cod[1:], g.cod[:1])\
@ Diagram.id(g.cod[1:])\
>> Diagram.id(f.cod[:1] @ g.cod[:1] @ f.cod[1:2])\
@ Diagram.swap(f.cod[2:], g.cod[1:2]) @ Diagram.id(g.cod[2:])
diagram2tensor = tensor.Functor(ob={
Ty("{}{}{}".format(a, b, c)):
z.__getattribute__(y).__getattribute__(x)
for a, x in zip(['c', 'q'], ['classical', 'quantum'])
for b, y in zip([0, 1], ['dom', 'cod'])
for c, z in zip([0, 1], [self, other])
},
ar={
f: self.utensor.array,
g: other.utensor.array
})
return CQMap(self.dom @ other.dom,
self.cod @ other.cod,
utensor=diagram2tensor(above >> f @ g >> below))
def eval(self, *others, backend=None, mixed=False, **params):
"""
Evaluate a circuit on a backend, or simulate it with numpy.
Parameters
----------
others : :class:`discopy.quantum.circuit.Circuit`
Other circuits to process in batch.
backend : pytket.Backend, optional
Backend on which to run the circuit, if none then we apply
:class:`discopy.tensor.Functor` or :class:`CQMapFunctor` instead.
mixed : bool, optional
Whether to apply :class:`discopy.tensor.Functor`
or :class:`CQMapFunctor`.
params : kwargs, optional
Get passed to Circuit.get_counts.
Returns
-------
tensor : :class:`discopy.tensor.Tensor`
If :code:`backend is not None` or :code:`mixed=False`.
cqmap : :class:`CQMap`
Otherwise.
Examples
--------
We can evaluate a pure circuit (i.e. with :code:`not circuit.is_mixed`)
as a unitary :class:`discopy.tensor.Tensor` or as a :class:`CQMap`:
>>> from discopy.quantum import *
>>> H.eval().round(2)
Tensor(dom=Dim(2), cod=Dim(2), array=[0.71, 0.71, 0.71, -0.71])
>>> H.eval(mixed=True).round(1) # doctest: +ELLIPSIS
CQMap(dom=Q(Dim(2)), cod=Q(Dim(2)), array=[0.5, ..., 0.5])
We can evaluate a mixed circuit as a :class:`CQMap`:
>>> assert Measure().eval()\\
... == CQMap(dom=Q(Dim(2)), cod=C(Dim(2)),
... array=[1, 0, 0, 0, 0, 0, 0, 1])
>>> circuit = Bits(1, 0) @ Ket(0) >> Discard(bit ** 2 @ qubit)
>>> assert circuit.eval() == CQMap(dom=CQ(), cod=CQ(), array=[1])
We can execute any circuit on a `pytket.Backend`:
>>> circuit = Ket(0, 0) >> sqrt(2) @ H @ X >> CX >> Measure() @ Bra(0)
>>> from discopy.quantum.tk import mockBackend
>>> backend = mockBackend({(0, 1): 512, (1, 0): 512})
>>> assert circuit.eval(backend, n_shots=2**10).round()\\
... == Tensor(dom=Dim(1), cod=Dim(2), array=[0., 1.])
"""
from discopy import cqmap
from discopy.quantum.gates import Bits, scalar, ClassicalGate
if len(others) == 1 and not isinstance(others[0], Circuit):
# This allows the syntax :code:`circuit.eval(backend)`
return self.eval(backend=others[0], mixed=mixed, **params)
if backend is None:
if others:
return [circuit.eval(mixed=mixed, **params)
for circuit in (self, ) + others]
functor = cqmap.Functor() if mixed or self.is_mixed\
else tensor.Functor(lambda x: x[0].dim, lambda f: f.array)
return functor(self)
circuits = [circuit.to_tk() for circuit in (self, ) + others]
results, counts = [], circuits[0].get_counts(
*circuits[1:], backend=backend, **params)
for i, circuit in enumerate(circuits):
n_bits = len(circuit.post_processing.dom)
result = Tensor.zeros(Dim(1), Dim(*(n_bits * (2, ))))
for bitstring, count in counts[i].items():
result += (scalar(count) @ Bits(*bitstring)).eval()
if circuit.post_processing:
result = result >> circuit.post_processing.eval()
results.append(result)
return results if len(results) > 1 else results[0]