QSVM multiclass classification¶

A multiclass extension works in conjunction with an underlying binary (two class) classifier to provide classification where the number of classes is greater than two.

Currently the following multiclass extensions are supported:

OneAgainstRest
AllPairs
ErrorCorrectingCode

These use different techniques to group the data from the binary classification to achieve the final multiclass classification.

[1]:

import numpy as np

from qiskit import BasicAer
from qiskit.circuit.library import ZZFeatureMap
from qiskit.aqua import QuantumInstance, aqua_globals
from qiskit.aqua.algorithms import QSVM
from qiskit.aqua.components.multiclass_extensions import AllPairs
from qiskit.aqua.utils.dataset_helper import get_feature_dimension

We want a dataset with more than two classes, so here we choose the Wine dataset that has 3 classes.

[2]:

from qiskit.ml.datasets import wine

n = 2  # dimension of each data point
sample_Total, training_input, test_input, class_labels = wine(training_size=24,
                                                              test_size=6, n=n, plot_data=True)
temp = [test_input[k] for k in test_input]
total_array = np.concatenate(temp)

/home/computertreker/git/qiskit/qiskit-dup/.tox/docs/lib/python3.7/site-packages/qiskit/ml/__init__.py:40: DeprecationWarning: The package qiskit.ml is deprecated. It was moved/refactored to qiskit_machine_learning (pip install qiskit-machine-learning). For more information see <https://github.com/Qiskit/qiskit-aqua/blob/master/README.md#migration-guide>
  warn_package('ml', 'qiskit_machine_learning', 'qiskit-machine-learning')

../../_images/tutorials_machine_learning_02_qsvm_multiclass_3_1.png

To used a multiclass extension an instance thereof simply needs to be supplied, on the QSVM creation, using the multiclass_extension parameter. Although AllPairs() is used in the example below, the following multiclass extensions would also work:

OneAgainstRest()
ErrorCorrectingCode(code_size=5)

[3]:

aqua_globals.random_seed = 10598

backend = BasicAer.get_backend('qasm_simulator')
feature_map = ZZFeatureMap(feature_dimension=get_feature_dimension(training_input),
                           reps=2, entanglement='linear')
svm = QSVM(feature_map, training_input, test_input, total_array,
           multiclass_extension=AllPairs())
quantum_instance = QuantumInstance(backend, shots=1024,
                                   seed_simulator=aqua_globals.random_seed,
                                   seed_transpiler=aqua_globals.random_seed)

result = svm.run(quantum_instance)
for k,v in result.items():
    print(f'{k} : {v}')

/home/computertreker/git/qiskit/qiskit-dup/.tox/docs/lib/python3.7/site-packages/ipykernel_launcher.py:1: DeprecationWarning: The variable qiskit.aqua.aqua_globals is deprecated. It was moved/refactored to qiskit.utils.algorithm_globals (pip install qiskit-terra). For more information see <https://github.com/Qiskit/qiskit-aqua/blob/master/README.md#migration-guide>
  """Entry point for launching an IPython kernel.
/home/computertreker/git/qiskit/qiskit-dup/.tox/docs/lib/python3.7/site-packages/qiskit/aqua/components/multiclass_extensions/multiclass_extension.py:34: DeprecationWarning: The package qiskit.aqua.components.multiclass_extensions is deprecated. For more information see <https://github.com/Qiskit/qiskit-aqua/blob/master/README.md#migration-guide>
  warn_package('aqua.components.multiclass_extensions')
/home/computertreker/git/qiskit/qiskit-dup/.tox/docs/lib/python3.7/site-packages/qiskit/aqua/algorithms/classifiers/qsvm/qsvm.py:104: DeprecationWarning: The package qiskit.aqua.algorithms.classifiers is deprecated. It was moved/refactored to qiskit_machine_learning.algorithms.classifiers (pip install qiskit-machine-learning). For more information see <https://github.com/Qiskit/qiskit-aqua/blob/master/README.md#migration-guide>
  'qiskit-machine-learning')
/home/computertreker/git/qiskit/qiskit-dup/.tox/docs/lib/python3.7/site-packages/qiskit/aqua/quantum_instance.py:137: DeprecationWarning: The class qiskit.aqua.QuantumInstance is deprecated. It was moved/refactored to qiskit.utils.QuantumInstance (pip install qiskit-terra). For more information see <https://github.com/Qiskit/qiskit-aqua/blob/master/README.md#migration-guide>
  'qiskit-terra')

testing_accuracy : 1.0
test_success_ratio : 1.0
predicted_labels : [0 1 2 2 2 2]
predicted_classes : ['A', 'B', 'C', 'C', 'C', 'C']

[4]:

import qiskit.tools.jupyter
%qiskit_version_table
%qiskit_copyright

Version Information

Qiskit Software	Version
Qiskit	0.25.4
Terra	0.17.2
Aer	0.8.2
Ignis	0.6.0
Aqua	0.9.1
IBM Q Provider	0.12.3
System information
Python	3.7.7 (default, Apr 22 2020, 19:15:10) [GCC 9.3.0]
OS	Linux
CPUs	32
Memory (Gb)	125.71903228759766
Tue May 25 16:27:21 2021 EDT

This code is a part of Qiskit

This code is licensed under the Apache License, Version 2.0. You may
obtain a copy of this license in the LICENSE.txt file in the root directory
of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.

Any modifications or derivative works of this code must retain this
copyright notice, and modified files need to carry a notice indicating
that they have been altered from the originals.