pyqpanda_alg.QLuoShu.VarModDou

Module Contents

Functions

VarModDou(qvec, aux, N)

Quantum Circuit for Variant Modular Doubling for Odd Modulo.

pyqpanda_alg.QLuoShu.VarModDou.VarModDou(qvec, aux, N)

Quantum Circuit for Variant Modular Doubling for Odd Modulo.

Parameters:

\(qvec\) : qlist

holds the integer \(x\)

aux : qubit

an auxiliary qubit to control constant modulo addition

\(N\) : int

the constant modulo

Return:

circuit : VarModDou.QCircuit

The circuit is used to compute modular doubling that \(|x \rangle |0 \rangle \rightarrow |2x \mod N\rangle|0\rangle\). The modular doubling circuit for a constant odd integer modulus \(N\). There are two changes that make it more efficient than the addition circuit. First, it works in place on only one \(n\)-qubit input integer \(|x \rangle\), with \(n=\lceil \log_{2}N \rceil\). Therefore it uses only \(n+1\) qubits.

Example:

If \(x =7, N=11\), putting \(x\) held in \(|qvec \rangle\). By the circuit, the result \(|0011 \rangle\) will be held in the \(|qvec \rangle\), i.e., \(2*7 \mod 11=3\).

from pyqpanda import *
import math
from pyqpanda_alg.QLuoShu import VarModDou

if __name__ == "__main__":
    N = 11
    x = 7
    n = math.ceil(math.log(N, 2))
    qvm = init_quantum_machine(QMachineType.CPU)
    prog = QProg()

    qvec = qvm.qAlloc_many(n)
    aux = qvm.qAlloc_many(1)

    prog << bind_nonnegative_data(x, qvec) \
         << VarModDou.VarModDou(qvec, aux, N)

    result = prob_run_dict(prog, qvec, 1)

    for key in result:
        print(key + ":" + str(result[key]))
        c = int(key, 2)
    print("2*%d mod %d=%d" % (x, N, c))

0011:0.9999999999999982
2*7 mod 11=3

Note that: \(N\) is an odd integer.