Dark Magic Operations

Warning

The operations in this section bypass the normal constraints of quantum mechanics and are not guaranteed to be unitary. Use them only for debugging, initialization, or when you clearly understand the consequences.

Dark magic operations provide the ability to directly modify the internal representation of a quantum state without going through normal quantum gate transformations. These operations do not correspond to any physical quantum operations.

Overview

Dark magic operations overview

Operator	Operation	Unitarity
Normalize	Normalize the quantum state	Non-unitary
Init_Unsafe	Set a register value directly	Non-unitary

—

Normalize

Operation: Normalizes the amplitudes of the entire SparseState so that \(\sum_i |\alpha_i|^2 = 1\).

Parameters: None.

Purpose: Use this operator to repair a quantum state that has been left unnormalized by manual manipulation (e.g. Init_Unsafe) or by numerical error.

import pysparq as ps

# Suppose some operations have left the quantum state unnormalized
ps.Normalize()(state)

# You can check it with ViewNormalization
ps.ViewNormalization()(state)

—

Init_Unsafe (unsafe initialization)

Operation: Directly sets the value of the specified register to a given constant, without going through any quantum gate.

Parameters:

• reg — target register (name or ID)

• value — the value to set (integer)

Behavior: Iterates over all basis states and forcibly sets the specified register’s value to value. If multiple basis states end up with duplicate keys after the assignment, their amplitudes are summed.

Warning

This operation is not guaranteed to be unitary. It destroys superposition information — if the register was in a superposition, all components other than value are overwritten.

import pysparq as ps

ps.System.clear()
ps.System.add_register("a", ps.UnsignedInteger, 4)
ps.System.add_register("b", ps.UnsignedInteger, 4)

state = ps.SparseState()

# Set the initial values directly
ps.Init_Unsafe("a", 3)(state)
ps.Init_Unsafe("b", 5)(state)

ps.pprint(state)
# |a=3,b=5⟩ : (1+0j)

Note

The most common use of Init_Unsafe is to set the initial values of the input registers at the start of an algorithm. Be especially careful when using it on a superposed state.

---

中文版 ===

黑魔法操作

警告

本节操作绕过正常的量子力学约束，不保证幺正性。仅在调试、初始化或明确了解后果时使用。

黑魔法操作提供直接修改量子态内部表示的能力，不经过正常的量子门变换。这些操作不对应任何物理量子操作。

概述

黑魔法操作总览

算子	操作	幺正性
Normalize	归一化量子态	非幺正
Init_Unsafe	直接设置寄存器值	非幺正

—

Normalize（归一化）

操作: 将整个 SparseState 的振幅归一化，使得 \(\sum_i |\alpha_i|^2 = 1\)。

参数: 无。

用途: 当手工操作（如 Init_Unsafe）或数值误差导致量子态未归一化时，使用此算子修复。

import pysparq as ps

# 假设某些操作导致量子态未归一化
ps.Normalize()(state)

# 可以通过 ViewNormalization 检查
ps.ViewNormalization()(state)

—

Init_Unsafe（不安全初始化）

操作: 直接将指定寄存器的值设置为给定常数，不经过任何量子门。

参数:

• reg — 目标寄存器（名称或 ID）

• value — 要设置的值（整数）

行为: 遍历所有基态，将指定寄存器的值强制设为 value。如果多个基态在设置后键值重复，它们的振幅会相加。

Warning

此操作 不保证幺正性。它会破坏叠加态信息——如果寄存器原本处于叠加态，所有非 value 的分量将被覆盖。

import pysparq as ps

ps.System.clear()
ps.System.add_register("a", ps.UnsignedInteger, 4)
ps.System.add_register("b", ps.UnsignedInteger, 4)

state = ps.SparseState()

# 直接设置初始值
ps.Init_Unsafe("a", 3)(state)
ps.Init_Unsafe("b", 5)(state)

ps.pprint(state)
# |a=3,b=5⟩ : (1+0j)

Note

Init_Unsafe 最常见的用途是在算法开始时设置输入寄存器的初值。在叠加态上使用时需格外小心。