measurement.py

# -*- coding: utf-8 -*-
"""
Created on Wed Feb 17 12:35:02 2021

@author: VED DHARKAR
"""


#! /usr/bin/python3
import pennylane as qml
from pennylane import numpy as np
import sys


def simple_circuits_20(angle):
    """The code you write for this challenge should be completely contained within this function
    between the # QHACK # comment markers.
    In this function:
        * Rotate the qubit around the x-axis by angle
        * Measure the probability the qubit is in the zero state
    Args:
        angle (float): how much to rotate a state around the x-axis
    Returns:
        float: the probability of of the state being in the 0 ground state
    """
    prob = 0.0
    # QHACK #

    # Step 1 : initalize a device
    num_wires = 2
    dev = qml.device('default.qubit', wires=num_wires)

    # Step 2 : Create a quantum circuit and qnode
    @qml.qnode(dev)
    def cir(param):
        qml.RX(angle, wires=0)
        return qml.probs(wires=0)

    # Step 3 : Run the qnode
    prob1 = cir(0.1)
    prob = prob1[0]

    # QHACK #
    return prob


if __name__ == "__main__":
    # DO NOT MODIFY anything in this code block

    # Load and process input
    angle_str = sys.stdin.read()
    angle = float(angle_str)

    ans = simple_circuits_20(angle)

    if isinstance(ans, np.tensor):
        ans = ans.item()

    if not isinstance(ans, float):
        raise TypeError("the simple_circuits_20 function needs to return a float")

    print(ans)