DraperQFTAdder¶

class
DraperQFTAdder
(num_state_qubits, kind='fixed', name='DraperQFTAdder')[source]¶ Bases:
qiskit.circuit.library.arithmetic.adders.adder.Adder
A circuit that uses QFT to perform inplace addition on two qubit registers.
For registers with \(n\) qubits, the QFT adder can perform addition modulo \(2^n\) (with
kind="fixed"
) or ordinary addition by adding a carry qubits (withkind="half"
).As an example, a nonfixed_point QFT adder circuit that performs addition on two 2qubit sized registers is as follows:
a_0: ─────────■──────■────────────────────────■──────────────── │ │ │ a_1: ─────────┼──────┼────────■──────■────────┼──────────────── ┌──────┐ │P(π) │ │ │ │ ┌───────┐ b_0: ┤0 ├─■──────┼────────┼──────┼────────┼───────┤0 ├ │ │ │P(π/2) │P(π) │ │ │ │ b_1: ┤1 qft ├────────■────────■──────┼────────┼───────┤1 iqft ├ │ │ │P(π/2) │P(π/4) │ │ cout_0: ┤2 ├────────────────────────■────────■───────┤2 ├ └──────┘ └───────┘
References:
[1] T. G. Draper, Addition on a Quantum Computer, 2000. arXiv:quantph/0008033
[2] RuizPerez et al., Quantum arithmetic with the Quantum Fourier Transform, 2017. arXiv:1411.5949
[3] Vedral et al., Quantum Networks for Elementary Arithmetic Operations, 1995. arXiv:quantph/9511018
 Parameters
num_state_qubits (
int
) – The number of qubits in either input register for state \(a\rangle\) or \(b\rangle\). The two input registers must have the same number of qubits.kind (
str
) – The kind of adder, can be'half'
for a half adder or'fixed'
for a fixedsized adder. A half adder contains a carryout to represent the mostsignificant bit, but the fixedsized adder doesn’t and hence performs addition modulo2 ** num_state_qubits
.name (
str
) – The name of the circuit object.
 Raises
ValueError – If
num_state_qubits
is lower than 1.
Attributes

ancillas
¶ Returns a list of ancilla bits in the order that the registers were added.

calibrations
¶ Return calibration dictionary.
 The custom pulse definition of a given gate is of the form
{‘gate_name’: {(qubits, params): schedule}}

clbits
¶ Returns a list of classical bits in the order that the registers were added.

data
¶ Return the circuit data (instructions and context).
 Returns
a listlike object containing the tuples for the circuit’s data.
Each tuple is in the format
(instruction, qargs, cargs)
, where instruction is an Instruction (or subclass) object, qargs is a list of Qubit objects, and cargs is a list of Clbit objects. Return type
QuantumCircuitData

extension_lib
= 'include "qelib1.inc";'¶

global_phase
¶ Return the global phase of the circuit in radians.

header
= 'OPENQASM 2.0;'¶

instances
= 16¶

metadata
¶ The user provided metadata associated with the circuit
The metadata for the circuit is a user provided
dict
of metadata for the circuit. It will not be used to influence the execution or operation of the circuit, but it is expected to be passed between all transforms of the circuit (ie transpilation) and that providers will associate any circuit metadata with the results it returns from execution of that circuit.

num_ancillas
¶ Return the number of ancilla qubits.

num_clbits
¶ Return number of classical bits.

num_parameters
¶ Convenience function to get the number of parameter objects in the circuit.

num_qubits
¶ Return number of qubits.

num_state_qubits
¶ The number of state qubits, i.e. the number of bits in each input register.
 Return type
int
 Returns
The number of state qubits.

parameters
¶ Convenience function to get the parameters defined in the parameter table.

prefix
= 'circuit'¶

qubits
¶ Returns a list of quantum bits in the order that the registers were added.