SubSwapGate

class SubSwapGate

Bases: ConstantGate, QuditGate

The two-qudit subspace SWAP gate.

The subspace SWAP gate swaps between “qudit-levels” on a two-qudit gate. For example, a |01> to |20> swap would be the identity with the |01> row and |20> rows swapped.

__init__(radix, qudit_levels)

Construct a SubSwapGate.

Parameters:

• radix (int) – The number of qudit levels (>=2).

• qudit_levels (str) – The qudit levels that should be swapped, separated by a comma. Example: “0,1;2,0” to swap |01> to |20>

Raises:

• ValueError – if radix < 2

• ValueError – If any of the qudit levels integer represenation greater than or equal to radix.

• ValueError – If the qudit_levels string is not formatted correctly.

Attributes

dim	The matrix dimension for this unitary.
name	The name of this gate.
num_params	The number of real parameters this unitary-valued function takes.
num_qudits	The number of qudits this unitary can act on.
qasm_name	The qasm identifier for this gate.
radix	The number of levels in each qudit.
radixes	The number of orthogonal states for each qudit.

Methods

calculate_level_swap_unitary(radix, level1, ...)	Calculate the unitary for a qudit level swap.
check_env_matrix(env_matrix)	Check to ensure the env_matrix is validly shaped.
check_parameters(params)	Check parameters are valid and match the unitary.
decode_qudit_level_string(string)	Decode the qudit level string into two pairs of integers.
get_grad([params])	Return the gradient for this gate.
get_inverse()	Return the gate's inverse as a gate.
get_inverse_params([params])	Return the parameters that invert the gate.
get_qasm(params, location)	Returns the qasm string for this gate.
get_qasm_gate_def()	Returns a qasm gate definition block for this gate.
get_unitary([params])	Return the unitary for this gate, see Unitary for more.
get_unitary_and_grad([params])	Return the unitary and gradient for this gate.
is_constant()	Return true if this unitary doesn't take parameters.
is_parameterized()	Return true if this unitary is parameterized.
is_qubit_only()	Return true if this unitary can only act on qubits.
is_qudit_only(radix)	Return true if this unitary can only act on radix-qudits.
is_qutrit_only()	Return true if this unitary can only act on qutrits.
is_self_inverse([params])	Checks whether the unitary is its own inverse.
optimize(env_matrix)	Return the optimal parameters with respect to an environment matrix.
with_all_frozen_params(params)	Freeze all of a gate's parameters so they don't change from optimization.
with_frozen_params(frozen_params)	Freeze some of a gate's parameters so they don't change from optimization.