StatePreparation
class qiskit.circuit.library.StatePreparation(params, num_qubits=None, inverse=False, label=None, normalize=False)
Bases: Gate
Complex amplitude state preparation.
Class that implements the (complex amplitude) state preparation of some flexible collection of qubit registers.
Parameters
-
params (str |list |int |Statevector) –
- Statevector: Statevector to initialize to.
- list: vector of complex amplitudes to initialize to.
- string: labels of basis states of the Pauli eigenstates Z, X, Y. See
Statevector.from_label(). Notice the order of the labels is reversed with respect to the qubit index to be applied to. Example label ‘01’ initializes the qubit zero to and the qubit one to . - int: an integer that is used as a bitmap indicating which qubits to initialize to . Example: setting params to 5 would initialize qubit 0 and qubit 2 to and qubit 1 to .
-
num_qubits (int | None) – This parameter is only used if params is an int. Indicates the total number of qubits in the initialize call. Example: initialize covers 5 qubits and params is 3. This allows qubits 0 and 1 to be initialized to and the remaining 3 qubits to be initialized to .
-
inverse (bool) – if True, the inverse state is constructed.
-
label (str | None) – An optional label for the gate
-
normalize (bool) – Whether to normalize an input array to a unit vector.
Raises
QiskitError – num_qubits parameter used when params is not an integer
When a Statevector argument is passed the state is prepared using a recursive initialization algorithm, including optimizations, from [1], as well as some additional optimizations including removing zero rotations and double cnots.
References: [1] Shende, Bullock, Markov. Synthesis of Quantum Logic Circuits (2004) [https://arxiv.org/abs/quant-ph/0406176v5]
Attributes
condition_bits
Get Clbits in condition.
decompositions
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
definition
Return definition in terms of other basic gates.
duration
Get the duration.
label
Return instruction label
name
Return the name.
num_clbits
Return the number of clbits.
num_qubits
Return the number of qubits.
params
return instruction params.
unit
Get the time unit of duration.
Methods
broadcast_arguments
broadcast_arguments(qargs, cargs)
Validation and handling of the arguments and its relationship.
For example, cx([q[0],q[1]], q[2]) means cx(q[0], q[2]); cx(q[1], q[2]). This method yields the arguments in the right grouping. In the given example:
in: [[q[0],q[1]], q[2]],[]
outs: [q[0], q[2]], []
[q[1], q[2]], []The general broadcasting rules are:
If len(qargs) == 1:
[q[0], q[1]] -> [q[0]],[q[1]]If len(qargs) == 2:
[[q[0], q[1]], [r[0], r[1]]] -> [q[0], r[0]], [q[1], r[1]] [[q[0]], [r[0], r[1]]] -> [q[0], r[0]], [q[0], r[1]] [[q[0], q[1]], [r[0]]] -> [q[0], r[0]], [q[1], r[0]]If len(qargs) >= 3:
[q[0], q[1]], [r[0], r[1]], ...] -> [q[0], r[0], ...], [q[1], r[1], ...]
Parameters
- qargs – List of quantum bit arguments.
- cargs – List of classical bit arguments.
Returns
A tuple with single arguments.
Raises
CircuitError – If the input is not valid. For example, the number of arguments does not match the gate expectation.
inverse
inverse()
Return inverted StatePreparation
validate_parameter
validate_parameter(parameter)
StatePreparation instruction parameter can be str, int, float, and complex.