Initialize
class Initialize(params, num_qubits=None)
Bases: qiskit.circuit.instruction.Instruction
Complex amplitude initialization.
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.
Create new initialize composite.
Parameters

params (str, list, int or 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 $1\rangle$ 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 (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 $0\rangle$.
Methods
add_decomposition
Initialize.add_decomposition(decomposition)
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
Initialize.assemble()
Assemble a QasmQobjInstruction
broadcast_arguments
Initialize.broadcast_arguments(qargs, cargs)
Validation of the arguments.
Parameters
 qargs (List) – List of quantum bit arguments.
 cargs (List) – List of classical bit arguments.
Yields
Tuple(List, List) – 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.
c_if
Initialize.c_if(classical, val)
Set a classical equality condition on this instruction between the register or cbit classical
and value val
.
This is a setter method, not an additive one. Calling this multiple times will silently override any previously set condition; it does not stack.
copy
Initialize.copy(name=None)
Copy of the instruction.
Parameters
name (str) – name to be given to the copied circuit, if None then the name stays the same.
Returns
a copy of the current instruction, with the name
updated if it was provided
Return type
gates_to_uncompute
Initialize.gates_to_uncompute()
Call to create a circuit with gates that take the desired vector to zero.
Returns
circuit to take self.params vector to ${00\ldots0}\rangle$
Return type
inverse
Initialize.inverse()
Invert this instruction.
If the instruction is composite (i.e. has a definition), then its definition will be recursively inverted.
Special instructions inheriting from Instruction can implement their own inverse (e.g. T and Tdg, Barrier, etc.)
Returns
a fresh instruction for the inverse
Return type
Raises
CircuitError – if the instruction is not composite and an inverse has not been implemented for it.
is_parameterized
Initialize.is_parameterized()
Return True .IFF. instruction is parameterized else False
qasm
Initialize.qasm()
Return a default OpenQASM string for the instruction.
Derived instructions may override this to print in a different format (e.g. measure q[0] > c[0];).
repeat
Initialize.repeat(n)
Creates an instruction with gate repeated n amount of times.
Parameters
n (int) – Number of times to repeat the instruction
Returns
Containing the definition.
Return type
Raises
CircuitError – If n < 1.
reverse_ops
Initialize.reverse_ops()
For a composite instruction, reverse the order of subinstructions.
This is done by recursively reversing all subinstructions. It does not invert any gate.
Returns
a new instruction with
subinstructions reversed.
Return type
soft_compare
Initialize.soft_compare(other)
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.
Parameters
other (instruction) – other instruction.
Returns
are self and other equal up to parameter expressions.
Return type
bool
validate_parameter
Initialize.validate_parameter(parameter)
Instruction parameters has no validation or normalization.
Attributes
condition_bits
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
Return type
str
name
Return the name.
num_clbits
Return the number of clbits.
num_qubits
Return the number of qubits.
params
Return initialize params.
unit
Get the time unit of duration.