Reference: Modular Addition Qubricks¶

Contents¶

ModularAdd Class

ModularAdd Class¶

psiqworkbench.qubricks.qbk_modular_add.ModularAdd ¶

ModularAdd(adder_qubrick=None, **kwargs)

Bases: Qubrick

Modular addition: computes dst = (dst + rhs) % M, where M is a positive integer.

dst and rhs must store values less than M.

While this was implemented independently, it ended up similar to the one described in "How to compute a 256-bit elliptic curve private key with only 50 million Toffoli gates" (https://arxiv.org/abs/2306.08585 ⧉).

Parameters:

Name	Type	Description	Default
`adder_qubrick`	`Qubrick or None`	Qubrick to perform internal additions. Defaults to GidneyAdd.	`None`

compute ¶

compute(dst: QUInt, rhs: QUInt | int, M: int, ctrl: Qubits | None = None)

Computes dst = (dst + rhs) % M.

Parameters:

Name	Type	Description	Default
`dst`	`QUInt`	Register to add the number to.	required
`rhs`	`QUInt \| int`	The number to add to `dst`.	required
`M`	`int`	The modulo used for modular addition.	required
`ctrl`	`Qubits \| None`	Optional quantum control.	`None`

Note

dst and rhs must store values less than M, i.e., this modular add may wrap around at most once.