Statevector

class Statevector(data, dims=None)[source]

Statevector class

Initialize a statevector object.

Parameters
  • data (vector_like) – a complex statevector.

  • dims (int or tuple or list) – Optional. The subsystem dimension of the state (See additional information).

Raises

QiskitError – if input data is not valid.

Additional Information:

The dims kwarg can be None, an integer, or an iterable of integers.

  • Iterable – the subsystem dimensions are the values in the list with the total number of subsystems given by the length of the list.

  • Int or None – the length of the input vector specifies the total dimension of the density matrix. If it is a power of two the state will be initialized as an N-qubit state. If it is not a power of two the state will have a single d-dimensional subsystem.

Attributes

Statevector.atol

The absolute tolerance parameter for float comparisons.

Statevector.data

Return data.

Statevector.dim

Return total state dimension.

Statevector.num_qubits

Return the number of qubits if a N-qubit state or None otherwise.

Statevector.rtol

The relative tolerance parameter for float comparisons.

Methods

Statevector.__mul__(other)

Statevector.add(other)

Return the linear combination self + other.

Statevector.conjugate()

Return the conjugate of the operator.

Statevector.copy()

Make a copy of current operator.

Statevector.dims([qargs])

Return tuple of input dimension for specified subsystems.

Statevector.equiv(other[, rtol, atol])

Return True if statevectors are equivalent up to global phase.

Statevector.evolve(other[, qargs])

Evolve a quantum state by the operator.

Statevector.expand(other)

Return the tensor product state other ⊗ self.

Statevector.expectation_value(oper[, qargs])

Compute the expectation value of an operator.

Statevector.from_instruction(instruction)

Return the output statevector of an instruction.

Statevector.from_int(i, dims)

Return a computational basis statevector.

Statevector.from_label(label)

Return a tensor product of Pauli X,Y,Z eigenstates.

Statevector.is_valid([atol, rtol])

Return True if a Statevector has norm 1.

Statevector.measure([qargs])

Measure subsystems and return outcome and post-measure state.

Statevector.multiply(other)

Return the scalar multipled state other * self.

Statevector.probabilities([qargs, decimals])

Return the subsystem measurement probability vector.

Statevector.probabilities_dict([qargs, decimals])

Return the subsystem measurement probability dictionary.

Statevector.purity()

Return the purity of the quantum state.

Statevector.reset([qargs])

Reset state or subsystems to the 0-state.

Statevector.sample_counts(shots[, qargs])

Sample a dict of qubit measurement outcomes in the computational basis.

Statevector.sample_memory(shots[, qargs])

Sample a list of qubit measurement outcomes in the computational basis.

Statevector.seed([value])

Set the seed for the quantum state RNG.

Statevector.set_atol(value)

Set the class default absolute tolerance parameter for float comparisons.

Statevector.set_rtol(value)

Set the class default relative tolerance parameter for float comparisons.

Statevector.subtract(other)

Return the linear operator self - other.

Statevector.tensor(other)

Return the tensor product state self ⊗ other.

Statevector.to_counts()

Returns the statevector as a counts dict of probabilities.

Statevector.to_dict([decimals])

Convert the statevector to dictionary form.

Statevector.to_operator()

Convert state to a rank-1 projector operator

Statevector.trace()

Return the trace of the quantum state as a density matrix.

Statevector.__mul__(other)