qiskit.extensions.Initialize¶

class
Initialize
(params, num_qubits=None)[source]¶ Complex amplitude initialization.
Class that implements the (complex amplitude) initialization of some flexible collection of qubit registers. Note that Initialize is an Instruction and not a Gate since it contains a reset instruction, which is not unitary.
Create new initialize composite.
 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
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> and the qubit one to 0>.
 int: an integer that is used as a bitmap indicating which qubits to initialize
to 1>. Example: setting params to 5 would initialize qubit 0 and qubit 2 to 1> and qubit 1 to 0>.
 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> and the remaining 3 qubits to be initialized to 0>.

__init__
(params, num_qubits=None)[source]¶ Create new initialize composite.
 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
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> and the qubit one to 0>.
 int: an integer that is used as a bitmap indicating which qubits to initialize
to 1>. Example: setting params to 5 would initialize qubit 0 and qubit 2 to 1> and qubit 1 to 0>.
 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> and the remaining 3 qubits to be initialized to 0>.
Methods
__init__
(params[, num_qubits])Create new initialize composite.
add_decomposition
(decomposition)Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
()Assemble a QasmQobjInstruction
broadcast_arguments
(qargs, cargs)Validation of the arguments.
c_if
(classical, val)Add classical condition on register classical and value val.
copy
([name])Copy of the instruction.
Call to create a circuit with gates that take the desired vector to zero.
inverse
()Invert this instruction.
Return True .IFF.
mirror
()DEPRECATED: use instruction.reverse_ops().
qasm
()Return a default OpenQASM string for the instruction.
repeat
(n)Creates an instruction with gate repeated n amount of times.
For a composite instruction, reverse the order of subinstructions.
soft_compare
(other)Soft comparison between gates.
validate_parameter
(parameter)Initialize instruction parameter can be str, int, float, and complex.
Attributes
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
Return definition in terms of other basic gates.
Get the duration.
return instruction params.
Get the time unit of duration.

add_decomposition
(decomposition)¶ Add a decomposition of the instruction to the SessionEquivalenceLibrary.

assemble
()¶ Assemble a QasmQobjInstruction

broadcast_arguments
(qargs, cargs)[source]¶ 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
(classical, val)¶ Add classical condition on register classical and value val.

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

property
decompositions
¶ Get the decompositions of the instruction from the SessionEquivalenceLibrary.

property
definition
¶ Return definition in terms of other basic gates.

property
duration
¶ Get the duration.

gates_to_uncompute
()[source]¶ 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
()¶ 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
()¶ Return True .IFF. instruction is parameterized else False

mirror
()¶ DEPRECATED: use instruction.reverse_ops().
 Returns
 a new instruction with subinstructions
reversed.
 Return type

property
params
¶ return instruction params.

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
(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
()¶ 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
(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

property
unit
¶ Get the time unit of duration.