Operator

class Operator(data, input_dims=None, output_dims=None)

Matrix operator class

This represents a matrix operator \(M\) that will evolve() a Statevector \(|\psi\rangle\) by matrix-vector multiplication

\[|\psi\rangle \mapsto M|\psi\rangle,\]

and will evolve() a DensityMatrix \(\rho\) by left and right multiplication

\[\rho \mapsto M \rho M^\dagger.\]

Initialize an operator object.

Parameters

• or (data (QuantumCircuit) – Instruction or BaseOperator or matrix): data to initialize operator.

• input_dims (tuple) – the input subsystem dimensions. [Default: None]

• output_dims (tuple) – the output subsystem dimensions. [Default: None]

Raises

QiskitError – if input data cannot be initialized as an operator.

Additional Information:

If the input or output dimensions are None, they will be automatically determined from the input data. If the input data is a Numpy array of shape (2**N, 2**N) qubit systems will be used. If the input operator is not an N-qubit operator, it will assign a single subsystem with dimension specified by the shape of the input.

Attributes

Operator.atol	The default absolute tolerance parameter for float comparisons.
Operator.data	Return data.
Operator.dim	Return tuple (input_shape, output_shape).
Operator.num_qubits	Return the number of qubits if a N-qubit operator or None otherwise.
Operator.qargs	Return the qargs for the operator.
Operator.rtol	The relative tolerance parameter for float comparisons.

Methods

Operator.__call__(qargs)	Return a clone with qargs set
Operator.__mul__(other)
Operator.add(other)	Return the linear operator self + other.
Operator.adjoint()	Return the adjoint of the operator.
Operator.compose(other[, qargs, front])	Return the composed operator.
Operator.conjugate()	Return the conjugate of the operator.
Operator.copy()	Make a deep copy of current operator.
Operator.dot(other[, qargs])	Return the right multiplied operator self * other.
Operator.equiv(other[, rtol, atol])	Return True if operators are equivalent up to global phase.
Operator.expand(other)	Return the tensor product operator other ⊗ self.
Operator.from_label(label)	Return a tensor product of single-qubit operators.
Operator.input_dims([qargs])	Return tuple of input dimension for specified subsystems.
Operator.is_unitary([atol, rtol])	Return True if operator is a unitary matrix.
Operator.multiply(other)	Return the linear operator other * self.
Operator.output_dims([qargs])	Return tuple of output dimension for specified subsystems.
Operator.power(n)	Return the matrix power of the operator.
Operator.reshape([input_dims, output_dims])	Return a shallow copy with reshaped input and output subsystem dimensions.
Operator.set_atol(value)	Set the class default absolute tolerance parameter for float comparisons.
Operator.set_rtol(value)	Set the class default relative tolerance parameter for float comparisons.
Operator.subtract(other)	Return the linear operator self - other.
Operator.tensor(other)	Return the tensor product operator self ⊗ other.
Operator.to_instruction()	Convert to a UnitaryGate instruction.
Operator.to_operator()	Convert operator to matrix operator class
Operator.transpose()	Return the transpose of the operator.
Operator.__call__(qargs)	Return a clone with qargs set
Operator.__mul__(other)