working on half-adder

%% Cell type:code id: tags:

``` python

import pennylane as qml

from pennylane import numpy as np

```

%% Cell type:code id: tags:

``` python

dev1 = qml.device('default.qubit.autograd', wires = 4, shots =100000)

@qml.qnode(dev1)

def circuit(params):

    if params[0] == 1:

        qml.PauliX(wires=0)

    if params[1] == 1:

        qml.PauliX(wires=1)

    #return qml.probs(wires=[0,1])

    #return qml.probs(wires=1)

    qml.CNOT(wires=[0,2])

    qml.CNOT(wires=[1,2])

    qml.Toffoli(wires=[0,1,3])

    #return qml.state()

    #return qml.sample(qml.PauliZ(2))

    #return qml.expval(qml.PauliZ(2))

    return qml.probs(wires=[2,3])

#drawer = qml.draw(circuit)

p = [0,1]

print(circuit(p))

```

%% Output

    [0. 0. 1. 0.]

%% Cell type:code id: tags:

``` python

a = [1,1]

probs = circuit(a)

print(probs)

if (probs[0] == 1) carry = 0; sum = 0 #state = |00>

if (probs[1] == 1) carry = 0; sum = 0

print("Carry Probabilities:", probs[:2] )

```

%% Output

    [0. 1. 0. 0.]

    Carry Probabilities: [0. 1.]

%% Cell type:code id: tags:

``` python

drawer = qml.draw(circuit)

print(drawer(p))

```

%% Output

    0: ──X─╭●────╭●─┤

    1: ────│──╭●─├●─┤

    2: ────╰X─╰X─│──┤ ╭Probs

    3: ──────────╰X─┤ ╰Probs

%% Cell type:code id: tags:

``` python

dev2 = qml.device("default.qubit", wires=2)

@qml.qnode(dev2)

def apply_h_cnot():

    # APPLY THE OPERATIONS IN THE CIRCUIT

    qml.Hadamard(wires=0)

    qml.CNOT(wires=[1,0])

    return qml.state()

print(apply_h_cnot())

```

%% Output

    [0.70710678+0.j 0.        +0.j 0.70710678+0.j 0.        +0.j]

%% Cell type:code id: tags:

``` python

#import sys

#!conda install --yes --prefix {sys.prefix} pylatexenc

from qiskit import *

from qiskit.tools.visualization import plot_bloch_multivector

from qiskit.tools.visualization import plot_histogram

# Creating a circuit with 2 quantum bits and one classical bit

qc = QuantumCircuit(2,1)

# Preparing inputs

qc.x(0) # Comment this line to make Qbit0 = |0>

qc.x(1) # Comment this line to make Qbit1 = |0>

qc.barrier()

# Applying the CNOT gate

qc.cx(0,1)

qc.barrier()

# Measuring Qbit1 and put result to classical bit

qc.measure(1,0)

# Drawing the circuit diagram

#qc.draw(output='mpl')

# Run the experimient 1024 times and get stats

counts = execute(qc,Aer.get_backend('qasm_simulator')).result().get_counts()

plot_histogram(counts)

```

%% Output

    <Figure size 700x500 with 1 Axes>