fresh-qc-sim.py

import numpy as np
import random
import math
import cmath #so eval can work w/ complex #s
from datetime import datetime #for output file
import os #for directory stuff

#file input vs. cli interface handling -> edit so it can accomodate noise
input_mode = input('file input or cli input? ')

if input_mode == 'file':
    file_contents = []
    file_name = input('file name: ')
    with open(file_name, 'r') as file:
        for i in file:#make sure i is each new line
            file_contents.append(i.strip('\n'))
    file_commands = file_contents[3:]
    qnum = int(file_contents[0])
    simulation_type = file_contents[1]
    z_or_o = file_contents[2]
else:
    qnum = int(input("How many qubits: "))
    simulation_type = input("ideal or nonideal simulation: ")
    z_or_o = input('would you like to start in the 0 or 1 state: ')

zero_state = np.matrix([[1],[0]])
one_state = np.matrix([[0],[1]])
iterate = 1
while iterate <= qnum:
    if iterate == 1:
        if z_or_o == '0':
            x = zero_state
        elif z_or_o == '1':
            x = one_state
    if iterate == qnum:
        qstat = x
        print(qstat)
    else:
        x = np.kron(x,zero_state)
    iterate+=1

basis_states = []
for i in range(0, 2**qnum):
    basis_states.append(bin(i)[2:].zfill(qnum))
done = 'n'

things_done = []
gates = {}

def record(name):
    things_done.append(name)

#for 'j' write '1j'
def custom_gate(dimension):
    value_hold = []
    for y in range(dimension):
        for x in range(dimension):
            element = input('What value for position ({}, {}): '.format(y+1, x+1))
            element = element.strip("\"\'\\\/") #sanitizes input
            value_hold.append(eval(element))
    matrix = np.matrix(np.resize(value_hold, (dimension, dimension)))
    if np.allclose(np.dot(matrix, matrix.conj().T), np.eye(dimension)):
        try:
            save = input("Would you like to save this gate? y or n: ")
            if save == 'y':
                save_gate(matrix)
            else:
                matrix_name = input("Please input matrix name: ")
                gates[matrix_name] = matrix
                record(matrix_name)
            return np.dot(matrix, qstat)
        except ValueError:
            print("not same size as vector, not applying")
            return qstat
    else:
        print("Invalid gate (not unitary), not applying")
        return qstat

def save_gate(matrix):
    matrix_name = input('please input a name for your matrix: ')
    record(matrix_name)
    gates[matrix_name] = matrix#add folder stuff
    np.savetxt(matrix_name+'.txt', matrix, delimiter=',')

def apply(matrix, qstat):
    try:
        return np.dot(matrix, qstat)
    except ValueError:
        print("not same size as vector, not applying")
        return qstat

def norm(qstat):
    return math.sqrt(sum(float(i)**2 for i in qstat))

def normalize(qstat):
    norm_result = norm(qstat)
    return np.dot(1/(norm_result),qstat)

def projection(acceptable_stats):
    #create qnum*qnum diagonal matrix
    diag_gen = []
    for i in range(0, qnum**2):
        diag_gen.append(1)
    diagonal_matrix = np.diag(diag_gen)
    #list of indexes of allowed states
    position_nums = []
    for i in acceptable_stats:
        position_nums.append(basis_states.index(i))
    #modify diagonal matrix to comply with list
    for i in range(0, qnum**2):
        if i not in position_nums:
            for k in range(0, qnum**2):
                diagonal_matrix[i][k] = 0
    return diagonal_matrix

def probability(qstat, qnum_index):
    amplitude = np.array(qstat)[qnum_index][0]
    prob = abs(amplitude)**2
    return prob

#measurement in different bases?
def measurement(qstat, qnum_meas="all"):
    if qnum_meas != "all":
        qnum_meas = int(qnum_meas)
        zero_prob = 1 - probability(qstat, qnum_meas-1)
        rand = random.random()
        acceptable_stats = []
        if rand < zero_prob:
            #zero
            print(qnum_meas,' qubit measured as zero')
            record(str(qnum_meas)+' qubit measured as zero')
            for i in basis_states:
                if i[qnum_meas-1] == '0':
                    acceptable_stats.append(i)
        else:
            #one
            print(qnum_meas,' qubit measured as one')
            record(str(qnum_meas)+' qubit measured as one')
            for i in basis_states:
                if i[qnum_meas-1] == '1':
                    acceptable_stats.append(i)
        projection_result = projection(acceptable_stats)
        return normalize(np.dot(projection_result, qstat))
    else:
        probabilities = []
        for i in qstat:
            probabilities.append(probability(qstat, np.where(qstat==i)[0][0]))
        rand_int = random.random()
        zero_vector = np.zeros((qnum**2, 1))
        counter = 0
        for i in probabilities:
            if rand_int < sum(probabilities[:counter+1]):
                zero_vector[counter][0] = 1
                return zero_vector
            counter+=1

#actual running...add 'if' for file/cli input
if input_mode == 'cli':
    if simulation_type == 'ideal':
        while done == 'n':
            next_item = input("custom gate or measurement or import or prev used: ")
            if next_item == 'measurement':
                measure_num = input('input all or which qubit num you would like measured: ')
                qstat = measurement(qstat, measure_num)
                record('measurement: '+measure_num)
                print(qstat)
            elif next_item == 'import':
                file_read = input("input file name you would like to read: ")
                try:#add folder stuff
                    matrix_load = np.loadtxt(file_read, delimiter=',')
                    gates[file_read[:file_read.index('.')]] = matrix_load
                    print(gates)
                    try:
                        matrix = input("which gate from your file would you like to use: ")
                        qstat = apply(gates[matrix], qstat)
                        record(matrix)
                    except KeyError:
                        print('this gate does not seem to have been saved in the past. try custom gate')
                    print(qstat)
                except FileNotFoundError:
                    print("file not found, check your spelling")
            elif next_item == 'prev used':
                print('list of gates: ',gates)
                matrix = input("please input the matrix name: ")
                try:
                    qstat = apply(gates[matrix],qstat)
                    print(qstat)
                    record(matrix)
                except KeyError:
                    print("this gate does not seem to have been saved in the past. try custom gate")
            else:
                dimension = int(input("Please give the size of your gate: "))
                qstat = custom_gate(dimension)
                print(qstat)
            done = input("Done with your qubits? y or n: ")

#consider having user import decoherence times they wish, but own noise function
#nothing special has to be done for error correction?
#how do decohered qubits affect other decohered qubits?
    else:
        print('this is not done yet; sorry!')#maybe turn this into a flag instead
        #of an else statement so it works w/ file run too
else:
    #file input run
    for i in file_commands:
        if 'measure' in i:
            if any(k.isdigit() for k in i):
                num = i.strip('measurement\n ')
                qstat = measurement(qstat, num)
            else:
                qstat = measurement(qstat, 'all')
        else:
            matrix_load = np.loadtxt(i, delimiter=',')#add folder stuff
            qstat = apply(matrix_load, qstat)
        record(i)

#provides output
print("end state: ", qstat)
record("end state: "+str(qstat))

for i in basis_states:
    print('probability of |'+i+'> on measurement: ', probability(qstat, basis_states.index(i)))
    record('probability of |'+i+'> on measurement: '+str(probability(qstat, basis_states.index(i))))

#create text file from record list
filename = str(datetime.now())+'-qc-sim-run.txt'
with open(filename, 'w') as file:#add folder stuff??
    file.write(str(datetime.now())+'\n')
    for i in things_done:
        file.write(i+'\n')