279 lines
8.6 KiB
Plaintext
279 lines
8.6 KiB
Plaintext
---
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title: Initialize
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description: API reference for qiskit.extensions.Initialize
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in_page_toc_min_heading_level: 1
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python_api_type: class
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python_api_name: qiskit.extensions.Initialize
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---
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# Initialize
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<Class id="qiskit.extensions.Initialize" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.23/qiskit/extensions/quantum_initializer/initializer.py" signature="Initialize(params, num_qubits=None)" modifiers="class">
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Bases: [`qiskit.circuit.instruction.Instruction`](qiskit.circuit.Instruction "qiskit.circuit.instruction.Instruction")
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Complex amplitude initialization.
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Class that initializes some flexible collection of qubit registers, implemented by calling the `qiskit.extensions.StatePreparation` Class. Note that Initialize is an Instruction and not a Gate since it contains a reset instruction, which is not unitary.
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Create new initialize composite.
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**Parameters**
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* **params** (*str, list, int or* [*Statevector*](qiskit.quantum_info.Statevector "qiskit.quantum_info.Statevector")) –
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* Statevector: Statevector to initialize to.
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* list: vector of complex amplitudes to initialize to.
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* 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 $|0\rangle$.
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* 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 $|0\rangle$.
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* **num\_qubits** (*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 $|0\rangle$.
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## Methods
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### add\_decomposition
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<Function id="qiskit.extensions.Initialize.add_decomposition" signature="Initialize.add_decomposition(decomposition)">
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Add a decomposition of the instruction to the SessionEquivalenceLibrary.
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</Function>
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### assemble
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<Function id="qiskit.extensions.Initialize.assemble" signature="Initialize.assemble()">
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Assemble a QasmQobjInstruction
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</Function>
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### broadcast\_arguments
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<Function id="qiskit.extensions.Initialize.broadcast_arguments" signature="Initialize.broadcast_arguments(qargs, cargs)">
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Validation of the arguments.
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**Parameters**
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* **qargs** (*List*) – List of quantum bit arguments.
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* **cargs** (*List*) – List of classical bit arguments.
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**Yields**
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*Tuple(List, List)* – A tuple with single arguments.
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**Raises**
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**CircuitError** – If the input is not valid. For example, the number of arguments does not match the gate expectation.
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</Function>
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### c\_if
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<Function id="qiskit.extensions.Initialize.c_if" signature="Initialize.c_if(classical, val)">
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Set a classical equality condition on this instruction between the register or cbit `classical` and value `val`.
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<Admonition title="Note" type="note">
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This is a setter method, not an additive one. Calling this multiple times will silently override any previously set condition; it does not stack.
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</Admonition>
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</Function>
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### copy
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<Function id="qiskit.extensions.Initialize.copy" signature="Initialize.copy(name=None)">
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Copy of the instruction.
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**Parameters**
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**name** (*str*) – name to be given to the copied circuit, if None then the name stays the same.
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**Returns**
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**a copy of the current instruction, with the name**
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updated if it was provided
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**Return type**
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[qiskit.circuit.Instruction](qiskit.circuit.Instruction "qiskit.circuit.Instruction")
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</Function>
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### gates\_to\_uncompute
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<Function id="qiskit.extensions.Initialize.gates_to_uncompute" signature="Initialize.gates_to_uncompute()">
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Call to create a circuit with gates that take the desired vector to zero.
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**Returns**
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circuit to take self.params vector to $|{00\ldots0}\rangle$
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**Return type**
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[QuantumCircuit](qiskit.circuit.QuantumCircuit "qiskit.circuit.QuantumCircuit")
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</Function>
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### inverse
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<Function id="qiskit.extensions.Initialize.inverse" signature="Initialize.inverse()">
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Invert this instruction.
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If the instruction is composite (i.e. has a definition), then its definition will be recursively inverted.
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Special instructions inheriting from Instruction can implement their own inverse (e.g. T and Tdg, Barrier, etc.)
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**Returns**
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a fresh instruction for the inverse
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**Return type**
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[qiskit.circuit.Instruction](qiskit.circuit.Instruction "qiskit.circuit.Instruction")
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**Raises**
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**CircuitError** – if the instruction is not composite and an inverse has not been implemented for it.
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</Function>
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### is\_parameterized
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<Function id="qiskit.extensions.Initialize.is_parameterized" signature="Initialize.is_parameterized()">
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Return True .IFF. instruction is parameterized else False
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</Function>
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### qasm
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<Function id="qiskit.extensions.Initialize.qasm" signature="Initialize.qasm()">
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Return a default OpenQASM string for the instruction.
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Derived instructions may override this to print in a different format (e.g. measure q\[0] -> c\[0];).
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</Function>
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### repeat
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<Function id="qiskit.extensions.Initialize.repeat" signature="Initialize.repeat(n)">
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Creates an instruction with gate repeated n amount of times.
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**Parameters**
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**n** (*int*) – Number of times to repeat the instruction
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**Returns**
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Containing the definition.
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**Return type**
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[qiskit.circuit.Instruction](qiskit.circuit.Instruction "qiskit.circuit.Instruction")
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**Raises**
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**CircuitError** – If n \< 1.
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</Function>
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### reverse\_ops
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<Function id="qiskit.extensions.Initialize.reverse_ops" signature="Initialize.reverse_ops()">
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For a composite instruction, reverse the order of sub-instructions.
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This is done by recursively reversing all sub-instructions. It does not invert any gate.
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**Returns**
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**a new instruction with**
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sub-instructions reversed.
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**Return type**
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[qiskit.circuit.Instruction](qiskit.circuit.Instruction "qiskit.circuit.Instruction")
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</Function>
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### soft\_compare
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<Function id="qiskit.extensions.Initialize.soft_compare" signature="Initialize.soft_compare(other)">
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Soft comparison between gates. Their names, number of qubits, and classical bit numbers must match. The number of parameters must match. Each parameter is compared. If one is a ParameterExpression then it is not taken into account.
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**Parameters**
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**other** (*instruction*) – other instruction.
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**Returns**
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are self and other equal up to parameter expressions.
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**Return type**
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bool
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</Function>
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### validate\_parameter
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<Function id="qiskit.extensions.Initialize.validate_parameter" signature="Initialize.validate_parameter(parameter)">
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Instruction parameters has no validation or normalization.
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</Function>
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## Attributes
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### condition\_bits
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<Attribute id="qiskit.extensions.Initialize.condition_bits">
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Get Clbits in condition.
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**Return type**
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`List`\[[`Clbit`](qiskit.circuit.Clbit "qiskit.circuit.classicalregister.Clbit")]
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</Attribute>
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### decompositions
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<Attribute id="qiskit.extensions.Initialize.decompositions">
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Get the decompositions of the instruction from the SessionEquivalenceLibrary.
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</Attribute>
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### definition
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<Attribute id="qiskit.extensions.Initialize.definition">
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Return definition in terms of other basic gates.
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</Attribute>
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### duration
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<Attribute id="qiskit.extensions.Initialize.duration">
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Get the duration.
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</Attribute>
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### label
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<Attribute id="qiskit.extensions.Initialize.label">
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Return instruction label
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**Return type**
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`str`
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</Attribute>
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### name
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<Attribute id="qiskit.extensions.Initialize.name">
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Return the name.
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</Attribute>
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### num\_clbits
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<Attribute id="qiskit.extensions.Initialize.num_clbits">
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Return the number of clbits.
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</Attribute>
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### num\_qubits
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<Attribute id="qiskit.extensions.Initialize.num_qubits">
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Return the number of qubits.
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</Attribute>
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### params
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<Attribute id="qiskit.extensions.Initialize.params">
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Return initialize params.
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</Attribute>
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### unit
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<Attribute id="qiskit.extensions.Initialize.unit">
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Get the time unit of duration.
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</Attribute>
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</Class>
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