PennyLaneCircuit#

class discopy.quantum.pennylane.PennyLaneCircuit(ops, params, wires, probabilities, post_selection, scale, n_qubits, device)[source]#

Bases: object

Implement a pennylane circuit with post-selection.

property post_selection#: The post-selection dictionary.

contains_sympy()[source]#

Determine if the circuit parameters are concrete or contain SymPy symbols.

Returns: Whether the circuit parameters contain SymPy symbols.
Return type: bool

draw(symbols=None, weights=None)[source]#

Print a string representation of the circuit similar to qml.draw, but including post-selection.

Parameters

symbols (list of sympy.core.symbol.Symbol, default: None) – The symbols from the original DisCoPy circuit.
weights (list of torch.FloatTensor, default: None) – The weights to substitute for the symbols.

get_valid_states()[source]#

Determine which of the output states of the circuit are compatible with the post-selections.

Returns: The indices of the circuit output that are compatible with the post-selections.
Return type: list of int

make_circuit()[source]#

Construct the qml.Qnode, a circuit that can be used with autograd to construct hybrid models.

Returns: A Pennylane circuit without post-selection.
Return type: qml.Qnode

post_selected_circuit(params)[source]#

Run the circuit with the given parameters and return the post-selected output.

Parameters: params (torch.FloatTensor) – The concrete parameters for the gates in the circuit.
Returns: The post-selected output of the circuit.
Return type: torch.Tensor

param_substitution(symbols, weights)[source]#

Substitute symbolic parameters (SymPy symbols) with floats.

Parameters

symbols (list of sympy.core.symbol.Symbol) – The symbols from the original DisCoPy circuit.
weights (list of torch.FloatTensor) – The weights to substitute for the symbols.

Returns

The concrete (non-symbolic) parameters for the circuit.

Return type

torch.FloatTensor

eval(symbols=None, weights=None)[source]#

Evaluate the circuit. The symbols should be those from the original DisCoPy diagram, which will be substituted for the concrete parameters in weights.

Parameters

symbols (list of sympy.core.symbol.Symbol, default: None) – The symbols from the original DisCoPy circuit.
weights (list of torch.FloatTensor, default: None) – The weights to substitute for the symbols.

Returns

The post-selected output of the circuit.

Return type

torch.Tensor