math

A tiny math library which will be extended thoughout the next weeks. Right now, it only contains the math functions necessary to run Beauregard’s implementation of Shor’s algorithm.

projectq.libs.math.all_defined_decomposition_rules	list() -> new empty list list(iterable) -> new list initialized from iterable’s items
projectq.libs.math.AddConstant(a)	Add a constant to a quantum number represented by a quantum register, stored from low- to high-bit.
projectq.libs.math.SubConstant(a)	Subtract a constant from a quantum number represented by a quantum register, stored from low- to high-bit.
projectq.libs.math.AddConstantModN(a, N)	Add a constant to a quantum number represented by a quantum register modulo N.
projectq.libs.math.SubConstantModN(a, N)	Subtract a constant from a quantum number represented by a quantum register modulo N.
projectq.libs.math.MultiplyByConstantModN(a, N)	Multiply a quantum number represented by a quantum register by a constant modulo N.

Module contents

class projectq.libs.math.AddConstant(a)

Add a constant to a quantum number represented by a quantum register, stored from low- to high-bit.

Example

qunum = eng.allocate_qureg(5) # 5-qubit number
X | qunum[1] # qunum is now equal to 2
AddConstant(3) | qunum # qunum is now equal to 5

__init__(a)

Initializes the gate to the number to add.

Parameters:a (int) – Number to add to a quantum register.

It also initializes its base class, BasicMathGate, with the corresponding function, so it can be emulated efficiently.

get_inverse()

Return the inverse gate (subtraction of the same constant).

class projectq.libs.math.AddConstantModN(a, N)

Add a constant to a quantum number represented by a quantum register modulo N.

The number is stored from low- to high-bit, i.e., qunum[0] is the LSB.

Example

qunum = eng.allocate_qureg(5) # 5-qubit number
X | qunum[1] # qunum is now equal to 2
AddConstantModN(3, 4) | qunum # qunum is now equal to 1

__init__(a, N)

Initializes the gate to the number to add modulo N.

Parameters:

• a (int) – Number to add to a quantum register (0 <= a < N).
• N (int) – Number modulo which the addition is carried out.

It also initializes its base class, BasicMathGate, with the corresponding function, so it can be emulated efficiently.

get_inverse()

Return the inverse gate (subtraction of the same number a modulo the same number N).

class projectq.libs.math.MultiplyByConstantModN(a, N)

Multiply a quantum number represented by a quantum register by a constant modulo N.

The number is stored from low- to high-bit, i.e., qunum[0] is the LSB.

Example

qunum = eng.allocate_qureg(5) # 5-qubit number
X | qunum[2] # qunum is now equal to 4
MultiplyByConstantModN(3,5) | qunum # qunum is now 2.

__init__(a, N)

Initializes the gate to the number to multiply with modulo N.

Parameters:

• a (int) – Number by which to multiply a quantum register (0 <= a < N).
• N (int) – Number modulo which the multiplication is carried out.

It also initializes its base class, BasicMathGate, with the corresponding function, so it can be emulated efficiently.

projectq.libs.math.SubConstant(a)

Subtract a constant from a quantum number represented by a quantum register, stored from low- to high-bit.

Parameters:a (int) – Constant to subtract

Example

qunum = eng.allocate_qureg(5) # 5-qubit number
X | qunum[2] # qunum is now equal to 4
SubConstant(3) | qunum # qunum is now equal to 1

projectq.libs.math.SubConstantModN(a, N)

Subtract a constant from a quantum number represented by a quantum register modulo N.

The number is stored from low- to high-bit, i.e., qunum[0] is the LSB.

Parameters:

• a (int) – Constant to add
• N (int) – Constant modulo which the addition of a should be carried out.

Example

qunum = eng.allocate_qureg(3) # 3-qubit number
X | qunum[1] # qunum is now equal to 2
SubConstantModN(4,5) | qunum # qunum is now -2 = 6 = 1 (mod 5)