blqs_cirq: Taking the pain out of writing Cirq programs

Blqs_cirq is a library that uses blqs to make it easier to write Cirq programs.

Here is the creation of a simple circuit in Cirq

import cirq
circuit = cirq.Circuit()
q0, q1 = cirq.LineQubit.range(2)
circuit.append(cirq.H(q0))
circuit.append(cirq.CX(q0, q1))
circuit.append(measure(q0, key='a'))

Blqs_cirq makes it so that you can write this more like a normal imperative program

import blqs_cirq as bc
from blqs_cirq import CX, H, measure

# Write the function imperatively.
@bc.build
def my_circuit():
    H(0)
    CX(0, 1)
    measure(q0, key='a')

# To create the circuit we simply call the function.
circuit = my_circuit()

Blqs provides supports for all the gates in Cirq, along with all the various ways to use these gates to create operations.

But wait, there is more. Blqs_cirq supports

• Simplification of qubit specification. Instead of creating LineQubit or NamedQubit, etc., one can simply use integers (converted to LineQubits), 2-tuples or 2-lists (converted to GridQubits) or strings (converted to NamedQubits). Custom conversions are also possible.

• Simplification of control flow primitives. For example Cirq currently supports a subcircuit which can be repeated. For example here we repeat a small circuit within our circuit:

@bc.build
def my_circuit():
    H(1)
    with Repeat(repetitions=10):
        H(0)
        CX(0, 1)

As more control operations are added to Cirq these will be added to blqs_cirq.

• Simple building of Moments. For example, the code below builds two moments:

@bc.build
def my_circuit():
    with Moment():
        bc.H(0)
    with Moment():
        bc.H(1)

• Support for Cirq's insertion strategies:

@bc.build
def my_circuit():
    with bc.InsertStrategy(cirq.InsertStrategy.NEW):
        H(0)
        H(1)

Installation

To install blqs_cirq one can simply pip install the appropriate package

pip install blqs_cirq

Note that installing blqs_cirq will also install blqs and cirq.

Documentation

A good place to start is with the introduction, followed by a look at the important features. For a quick intro via a jupyter notebook, see hello blqs_cirq.