added changes

%% Cell type:code id: tags:

``` python

import cirq

q0, q1, q2, q3 = cirq.LineQubit.range(4)

circuit = cirq.Circuit()

circuit.append(cirq.X(q1))

#circuit.append(cirq.X(q1))

circuit.append(cirq.X(q1))

circuit.append(cirq.CNOT(q0, q2))

circuit.append(cirq.CNOT(q1, q2))

circuit.append(cirq.CCNOT(q0, q1, q3))

circuit.append(cirq.measure(q2, q3, key='result'))

print(circuit)

s = cirq.Simulator()

samples = s.run(circuit, repetitions=1000)

counts = samples.histogram(key= 'result')

counts = samples.histogram(key= 'resul')

print(counts)

```

%% Output

          ┌──┐

    0: ─────@────────────@─────────────────

            │            │

    1: ────X┼────X───@───@─────────────────

            │        │   │

    2: ─────X────────X───┼───M('result')───

                         │   │

    3: ──────────────────X───M─────────────

    0: ─────@────────@────────────────

            │        │

    1: ────X┼────@───@────────────────

            │    │   │

    2: ─────X────X───┼───M('resul')───

                     │   │

    3: ──────────────X───M────────────

          └──┘

    Counter({0: 1000})

    Counter({2: 1000})

%% Cell type:code id: tags:

``` python

```

%% Cell type:code id: tags:

``` python

from qiskit import QuantumCircuit

from qiskit.extensions import UnitaryGate

import numpy as np

matrix = [[0, 0, 0, 1],

        [0, 0, 1, 0],

        [1, 0, 0, 0],

        [0, 1, 0, 0]]

gate = UnitaryGate(matrix)

circuit = QuantumCircuit(3)

circuit.append(gate, [0, 1])

```

%% Output

    <qiskit.circuit.instructionset.InstructionSet at 0x7f9a41460d90>

%% Cell type:code id: tags:

``` python

m2 = np.square(matrix)

print(m2)

```

%% Output

    [[0 0 0 1]

     [0 0 1 0]

     [1 0 0 0]

     [0 1 0 0]]

%% Cell type:code id: tags:

``` python

from numpy import linalg as LA

eigenvalues, eigenvectors = LA.eig(m2)

print(eigenvectors)

```

%% Output

    [[ 5.00000000e-01+0.00000000e+00j  2.63941871e-16-5.00000000e-01j

       2.63941871e-16+5.00000000e-01j -5.00000000e-01+0.00000000e+00j]

     [ 5.00000000e-01+0.00000000e+00j -2.85804968e-18+5.00000000e-01j

      -2.85804968e-18-5.00000000e-01j -5.00000000e-01+0.00000000e+00j]

     [-5.00000000e-01+0.00000000e+00j -5.00000000e-01+0.00000000e+00j

      -5.00000000e-01-0.00000000e+00j -5.00000000e-01+0.00000000e+00j]

     [-5.00000000e-01+0.00000000e+00j  5.00000000e-01-1.34144886e-16j

       5.00000000e-01+1.34144886e-16j -5.00000000e-01+0.00000000e+00j]]

%% Cell type:code id: tags:

``` python

circuit.draw(output='mpl')

```

%% Output

    <Figure size 287.496x284.278 with 1 Axes>

%% Cell type:code id: tags:

``` python

```