Iris Dataset

Easy

The classic Iris flower dataset for quantum classification

Dataset Overview

Key characteristics and specifications

Samples

150

Features

4 (Sepal, Petal)

Classes

3 (Iris Species)

Difficulty

Easy

This dataset contains measurements of iris flowers from three different species. Each flower is described by four features: sepal length, sepal width, petal length, and petal width. This is an ideal starting point for quantum machine learning as the feature space is moderate and the classification task is well-understood.

Dataset Visualization

Iris dataset scatter plot showing three species clusters

Why Only 2 Classes?

Understanding the binary classification approach

Binary VQC Simplification

While the standard Iris dataset contains 3 species (Setosa, Versicolor, and Virginica), Variational Quantum Classifiers are often introduced as binary classifiers for simplicity and easier visualization of quantum decision boundaries.

Classes Used in This VQC:

•

Class 0: Setosa(First iris species)

•

Class 1: Versicolor(Second iris species)

✗

Class 2: Virginica(Excluded for binary classification)

The backend filters the dataset to keep only the first two classes using:mask = (y == 0) | (y == 1)

Quantum Encoding

How features are encoded into quantum states

Amplitude Encoding

The four Iris features are normalized and encoded as amplitudes in a quantum state with 3 qubits (for 3 classes).

Encoded state representation:

where

Each of the four features undergoes normalization:

where

is the mean and

is the standard deviation of the feature across all samples.

VQC Cost Function

Quantum optimization objective

Binary Cross-Entropy Loss

For multi-class classification, the VQC uses the one-vs-rest strategy with binary classifiers.

where:

•

= number of training samples (150)

•

= VQC prediction for sample n

•

= true label (0 or 1)

•

= trainable parameters

Feature Statistics

Statistical properties of each feature

Sepal Length

Mean: 5.84 cm | Std Dev: 0.83 cm

Sepal Width

Mean: 3.06 cm | Std Dev: 0.43 cm

Petal Length

Mean: 3.76 cm | Std Dev: 1.76 cm

Petal Width

Mean: 1.20 cm | Std Dev: 0.76 cm