Get a Tensorflow op that produces samples from given quantum circuits.

This function produces a non-differentiable op that will calculate batches of circuit samples given tensor batches of cirq.Circuits, parameter values, and a scalar telling the op how many samples to take.

# Simulate circuits with cirq.
my_op = tfq.get_sampling_op(backend=cirq.sim.Simulator())
# Simulate circuits with C++.
my_second_op = tfq.get_sampling_op()
# Prepare some inputs.
qubit = cirq.GridQubit(0, 0)
my_symbol = sympy.Symbol('alpha')
my_circuit_tensor = tfq.convert_to_tensor(
my_values = np.array([[2.0]])
n_samples = np.array([10])
# This op can now be run to take samples.
output = my_second_op(
    my_circuit_tensor, ['alpha'], my_values, n_samples)
<tf.RaggedTensor [[[0], [0], [0], [0], [0], [0], [0], [0], [0], [0]]]>

backend Optional Python object that specifies what backend this op should use when evaluating circuits. Can be any cirq.Sampler. If not provided the default C++ sampling op is returned.
quantum_concurrent Optional Python bool. True indicates that the returned op should not block graph level parallelism on itself when executing. False indicates that graph level parallelism on itself should be blocked. Defaults to value specified in tfq.get_quantum_concurrent_op_mode which defaults to True (no blocking). This flag is only needed for advanced users when using TFQ for very large simulations, or when running on a real chip.

A callable with the following signature:

op(programs, symbol_names, symbol_values, num_samples)

programs tf.Tensor of strings with shape [batch_size] containing the string representations of the circuits to be executed.
symbol_names tf.Tensor of strings with shape [n_params], which is used to specify the order in which the values in symbol_values should be placed inside of the circuits in programs.
symbol_values tf.Tensor of real numbers with shape [batch_size, n_params] specifying parameter values to resolve into the circuits specified by programs, following the ordering dictated by symbol_names.
num_samples tf.Tensor with one element indicating the number of samples to draw.
Returns tf.Tensor with shape [batch_size, num_samples, n_qubits] that holds samples (as boolean values) for each circuit.