qrisp.QuantumModulus.inpl_mult

QuantumModulus.inpl_mult(factor: int | np.integer | Array | BigInteger, inverse: int | np.integer | Array | BigInteger | None = None) → QuantumModulus

Multiply the register in place by a classical factor, optionally with its precomputed inverse.

qm.inpl_mult(X) is the same as qm *= X. To uncompute a temporary register, the in-place multiplication also multiplies by the inverse of \(X\) modulo \(N\), and computing this inverse is its most expensive classical step. If the inverse is known in advance, for example for the powers \(a^{2^i}\) of Shor’s algorithm, passing it skips this computation. The circuit is the same.

Parameters:

factorint, Array or BigInteger

The classical factor \(X\), coprime to the modulus. NumPy integers are accepted as well.

inverseint, Array or BigInteger, optional

The inverse of \(X\) modulo \(N\). It is not checked. The default is None, which computes it.

Returns:

QuantumModulus

The register, multiplied in place.

Raises:

TypeError

If the factor or the inverse is not a classical integer.

Examples

Multiply by 7 modulo 15, whose inverse modulo 15 is 13:

>>> from qrisp import QuantumModulus
>>> qm = QuantumModulus(15)
>>> qm[:] = 2
>>> qm = qm.inpl_mult(7, inverse=13)
>>> print(qm)
{14: 1.0}