def plot_bloch_multivector(rho, title='', figsize=None):
"""Plot the Bloch sphere.
Plot a sphere, axes, the Bloch vector, and its projections onto each axis.
Args:
rho (ndarray): Numpy array for state vector or density matrix.
title (str): a string that represents the plot title
figsize (tuple): Has no effect, here for compatibility only.
Returns:
matplotlib.Figure:
A matplotlib figure instance.
Raises:
ImportError: Requires matplotlib.
Example:
.. jupyter-execute::
from qiskit import QuantumCircuit, BasicAer, execute
from qiskit.visualization import plot_bloch_multivector
%matplotlib inline
qc = QuantumCircuit(2, 2)
qc.h(0)
qc.cx(0, 1)
qc.measure([0, 1], [0, 1])
backend = BasicAer.get_backend('statevector_simulator')
job = execute(qc, backend).result()
plot_bloch_multivector(job.get_statevector(qc), title="New Bloch Multivector")
"""
if not HAS_MATPLOTLIB:
raise ImportError(
'Must have Matplotlib installed. To install, run "pip install '
'matplotlib".')
rho = _validate_input_state(rho)
num = int(np.log2(len(rho)))
width, height = plt.figaspect(1 / num)
fig = plt.figure(figsize=(width, height))
for i in range(num):
ax = fig.add_subplot(1, num, i + 1, projection='3d')
pauli_singles = [
Pauli.pauli_single(num, i, 'X'),
Pauli.pauli_single(num, i, 'Y'),
Pauli.pauli_single(num, i, 'Z')
]
bloch_state = list(
map(lambda x: np.real(np.trace(np.dot(x.to_matrix(), rho))),
pauli_singles))
plot_bloch_vector(bloch_state,
"qubit " + str(i),
ax=ax,
figsize=figsize)
fig.suptitle(title, fontsize=16)
if get_backend() in ['module://ipykernel.pylab.backend_inline', 'nbAgg']:
plt.close(fig)
return fig
def get_bloch_vectors(qc):
rho = what_is_the_density_matrix(qc)
bit_size = int(log2(rho.shape[0]))
bloch_array = []
for current_bit in range(bit_size):
x_component = np.real(
np.trace(
Pauli.pauli_single(bit_size, current_bit, 'X').to_matrix()
@ rho))
y_component = np.real(
np.trace(
Pauli.pauli_single(bit_size, current_bit, 'Y').to_matrix()
@ rho))
z_component = np.real(
np.trace(
Pauli.pauli_single(bit_size, current_bit, 'Z').to_matrix()
@ rho))
bloch_array.append([x_component, y_component, z_component])
return bloch_array
def plot_bloch_multivector(rho, title='', figsize=None):
"""Plot the Bloch sphere.
Plot a sphere, axes, the Bloch vector, and its projections onto each axis.
Args:
rho (ndarray): Numpy array for state vector or density matrix.
title (str): a string that represents the plot title
figsize (tuple): Has no effect, here for compatibility only.
Returns:
Figure: A matplotlib figure instance.
Raises:
ImportError: Requires matplotlib.
"""
if not HAS_MATPLOTLIB:
raise ImportError('Must have Matplotlib installed.')
rho = _validate_input_state(rho)
num = int(np.log2(len(rho)))
width, height = plt.figaspect(1 / num)
fig = plt.figure(figsize=(width, height))
for i in range(num):
ax = fig.add_subplot(1, num, i + 1, projection='3d')
pauli_singles = [
Pauli.pauli_single(num, i, 'X'),
Pauli.pauli_single(num, i, 'Y'),
Pauli.pauli_single(num, i, 'Z')
]
bloch_state = list(
map(lambda x: np.real(np.trace(np.dot(x.to_matrix(), rho))),
pauli_singles))
plot_bloch_vector(bloch_state,
"qubit " + str(i),
ax=ax,
figsize=figsize)
fig.suptitle(title, fontsize=16)
if get_backend() in ['module://ipykernel.pylab.backend_inline', 'nbAgg']:
plt.close(fig)
return fig
def iplot_bloch_multivector(rho, figsize=None):
""" Create a bloch sphere representation.
Graphical representation of the input array, using as much bloch
spheres as qubit are required.
Args:
rho (array): State vector or density matrix
figsize (tuple): Figure size in pixels.
Example:
.. code-block::
from qiskit import QuantumCircuit, BasicAer, execute
from qiskit.visualization import iplot_bloch_multivector
%matplotlib inline
qc = QuantumCircuit(2, 2)
qc.h(0)
qc.cx(0, 1)
qc.measure([0, 1], [0, 1])
backend = BasicAer.get_backend('statevector_simulator')
job = execute(qc, backend).result()
iplot_bloch_multivector(job.get_statevector(qc))
"""
# HTML
html_template = Template("""
<p>
<div id="content_$divNumber" style="position: absolute; z-index: 1;">
<div id="bloch_$divNumber"></div>
</div>
</p>
""")
# JavaScript
javascript_template = Template("""
<script>
requirejs.config({
paths: {
qVisualization: "https://qvisualization.mybluemix.net/q-visualizations"
}
});
data = $data;
dataValues = [];
for (var i = 0; i < data.length; i++) {
// Coordinates
var x = data[i][0];
var y = data[i][1];
var z = data[i][2];
var point = {'x': x,
'y': y,
'z': z};
dataValues.push(point);
}
require(["qVisualization"], function(qVisualizations) {
// Plot figure
qVisualizations.plotState("bloch_$divNumber",
"bloch",
dataValues,
$options);
});
</script>
""")
rho = _validate_input_state(rho)
if figsize is None:
options = {}
else:
options = {'width': figsize[0], 'height': figsize[1]}
# Process data and execute
num = int(np.log2(len(rho)))
bloch_data = []
for i in range(num):
pauli_singles = [Pauli.pauli_single(num, i, 'X'), Pauli.pauli_single(num, i, 'Y'),
Pauli.pauli_single(num, i, 'Z')]
bloch_state = list(map(lambda x: np.real(np.trace(np.dot(x.to_matrix(), rho))),
pauli_singles))
bloch_data.append(bloch_state)
div_number = str(time.time())
div_number = re.sub('[.]', '', div_number)
html = html_template.substitute({
'divNumber': div_number
})
javascript = javascript_template.substitute({
'data': bloch_data,
'divNumber': div_number,
'options': options
})
display(HTML(html + javascript))
