qiskit-documentation/docs/api/qiskit/0.36/qiskit.circuit.library.StatePreparation.mdx

---
title: StatePreparation
description: API reference for qiskit.circuit.library.StatePreparation
in_page_toc_min_heading_level: 1
python_api_type: class
python_api_name: qiskit.circuit.library.StatePreparation
---

# StatePreparation

<Class id="qiskit.circuit.library.StatePreparation" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.20/qiskit/circuit/library/data_preparation/state_preparation.py" signature="StatePreparation(params, num_qubits=None, inverse=False, label=None)" modifiers="class">
  Bases: `qiskit.circuit.gate.Gate`

  Complex amplitude state preparation.

  Class that implements the (complex amplitude) state preparation of some flexible collection of qubit registers.

  **Parameters**

  *   **params** (`Union`\[`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()`](qiskit.quantum_info.Statevector#from_label "qiskit.quantum_info.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 $|1\rangle$ and the qubit one to $|0\rangle$.
      *   int: an integer that is used as a bitmap indicating which qubits to initialize to $|1\rangle$. Example: setting params to 5 would initialize qubit 0 and qubit 2 to $|1\rangle$ and qubit 1 to $|0\rangle$.

  *   **num\_qubits** (`Optional`\[`int`]) – 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 $|1\rangle$ and the remaining 3 qubits to be initialized to $|0\rangle$.

  *   **inverse** (`bool`) – if True, the inverse state is constructed.

  *   **label** (`Optional`\[`str`]) – An optional label for the gate

  **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](https://arxiv.org/abs/quant-ph/0406176v5)]

  ## Methods Defined Here

  ### broadcast\_arguments

  <Function id="qiskit.circuit.library.StatePreparation.broadcast_arguments" signature="StatePreparation.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:

    ```python
    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:
    >
    >     ```python
    >     [q[0], q[1]] -> [q[0]],[q[1]]
    >     ```
    >
    > *   If len(qargs) == 2:
    >
    >     ```python
    >     [[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:
    >
    >     ```python
    >     [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.
  </Function>

  ### inverse

  <Function id="qiskit.circuit.library.StatePreparation.inverse" signature="StatePreparation.inverse()">
    Return inverted StatePreparation
  </Function>

  ### validate\_parameter

  <Function id="qiskit.circuit.library.StatePreparation.validate_parameter" signature="StatePreparation.validate_parameter(parameter)">
    StatePreparation instruction parameter can be str, int, float, and complex.
  </Function>

  ## Attributes

  ### condition\_bits

  <Attribute id="qiskit.circuit.library.StatePreparation.condition_bits">
    Get Clbits in condition.

    **Return type**

    `List`\[`Clbit`]
  </Attribute>

  ### decompositions

  <Attribute id="qiskit.circuit.library.StatePreparation.decompositions">
    Get the decompositions of the instruction from the SessionEquivalenceLibrary.
  </Attribute>

  ### definition

  <Attribute id="qiskit.circuit.library.StatePreparation.definition">
    Return definition in terms of other basic gates.
  </Attribute>

  ### duration

  <Attribute id="qiskit.circuit.library.StatePreparation.duration">
    Get the duration.
  </Attribute>

  ### label

  <Attribute id="qiskit.circuit.library.StatePreparation.label">
    Return instruction label

    **Return type**

    `str`
  </Attribute>

  ### name

  <Attribute id="qiskit.circuit.library.StatePreparation.name">
    Return the name.
  </Attribute>

  ### num\_clbits

  <Attribute id="qiskit.circuit.library.StatePreparation.num_clbits">
    Return the number of clbits.
  </Attribute>

  ### num\_qubits

  <Attribute id="qiskit.circuit.library.StatePreparation.num_qubits">
    Return the number of qubits.
  </Attribute>

  ### params

  <Attribute id="qiskit.circuit.library.StatePreparation.params">
    return instruction params.
  </Attribute>

  ### unit

  <Attribute id="qiskit.circuit.library.StatePreparation.unit">
    Get the time unit of duration.
  </Attribute>
</Class>