quantum/lib_q_computer_old.py

72 lines
2.0 KiB
Python
Raw Normal View History

2019-12-04 17:17:36 +01:00
"""
TODO: DEPRECATE THIS ONE IN FAVOR OF lib_q_computer.py
"""
import random
import numpy as np
# |0> and |1>
_0 = np.array([[1],
[0]])
_1 = np.array([[0],
[1]])
# |+> and |->
_p = np.array([[1 / np.sqrt(2)],
[1 / np.sqrt(2)]])
_m = np.array([[1 / np.sqrt(2)],
[-1 / np.sqrt(2)]])
# Gates - Identity, Pauli X and Hadamard
I = np.array([[1, 0],
[0, 1]])
X = np.array([[0, 1],
[1, 0]])
H = np.array([[1 / np.sqrt(2), 1 / np.sqrt(2)],
[1 / np.sqrt(2), -1 / np.sqrt(2)]])
def measure_probability(qbit):
"""
In a qbit [a, b] normalized: |a|^2 + |b|^2 = 1
Probability of 0 is |a|^2 and 1 with prob |b|^2
:returns: tuple of probabilities to measure 0 or 1"""
return np.abs(qbit[0][0]) ** 2, np.abs(qbit[1][0]) ** 2
def measure(qbit):
"""
This gets a random choice of either 0 and 1 with weights
based on the probabilities of the qbit
:returns: classical bit based on qbit probabilities"""
return random.choices([0, 1], measure_probability(qbit))[0]
def run_qbit_tests():
# asserts are sets of tests to check if mathz workz
# Identity: verify that I|0> == |0> and I|1> == |0>
assert np.array_equal(I.dot(_0), _0)
assert np.array_equal(I.dot(_1), _1)
# Pauli X: verify that X|0> == |1> and X|1> == |0>
assert np.array_equal(X.dot(_0), _1)
assert np.array_equal(X.dot(_1), _0)
# measure probabilities in sigma_x of |0> and |1>
# using allclose since dealing with floats
assert np.allclose(measure_probability(_0), (1.0, 0.0))
assert np.allclose(measure_probability(_1), (0.0, 1.0))
# applying Hadamard puts the qbit in orthogonal +/- basis
assert np.array_equal(H.dot(_0), _p)
assert np.array_equal(H.dot(_1), _m)
# measure probabilities in sigma_x of |+> and |->
# using allclose since dealing with floats
assert np.allclose(measure_probability(_p), (0.5, 0.5))
assert np.allclose(measure_probability(_m), (0.5, 0.5))