Entropy Calculation for Binary Classification using SciPy

In the code, we define the target variable y by converting multi-classification into a binary classification tasks for simplicity.

  • Here, we will use iris dataset and classify Setosa (class 0) vs. Non-Setosa (class 1) species.
  • Using np.bincount, we compute the frequency of each unique value in the target variable, which essentially gives us the counts of class 0 and class 1.
  • Finally, we pass these counts to the entropy function along with the base of 2 to compute the entropy of the target variable.
Python

from sklearn import datasets from scipy.stats import entropy import numpy as np iris = datasets.load_iris() X = iris.data # For simplicity, we'll classify the Iris species into two classes: Setosa (class 0) and Non-Setosa (class 1) y = (iris.target != 0).astype(int) # Setosa (class 0) vs Non-Setosa (class 1) y_entropy = entropy(np.bincount(y), base=2) # Compute the entropy of the target variable (y) print("Entropy of Iris dataset (binary classification):", y_entropy)

Output:

Entropy of Iris dataset (binary classification): 0.9182958340544894

How to Compute Entropy using SciPy?

Entropy is a fundamental concept in measuring the uncertainty or randomness in a dataset. Entropy plays a very significant role in machine learning models such as decision trees, helping to decide how best to partition input at each node. Even for those who are not very knowledgeable in the underlying mathematics, the Scipy library for Python, provides features that make computing entropy simple.

In this post, we will understand how to compute entropy using Popular python’s library scipy.

How to Compute Entropy using SciPy?

  • What is Entropy?
  • Why Compute Entropy?
  • Calculating Entropy with SciPy
  • Entropy Calculation for Binary Classification using Scipy
  • Entropy Calculation for Multi-Class Classification using Scipy
  • Conclusion
  • How to Compute Entropy using SciPy?- FAQs

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What is Entropy?

Entropy, introduced by Claude Shannon is a measure of the amount of uncertainty or randomness in a probability distribution. It is computed by taking the logarithm of each outcome’s probability and adding up all of its negative sums. Entropy is a measure of a dataset’s impurity or uncertainty in machine learning, and it is crucial for decision tree-based algorithms....

Why Compute Entropy?

Machine learning requires the computation of entropy for a number of reasons....

Calculating Entropy with SciPy

SciPy, provides an effecient way for calculating entropy using the “entropy" function from “scipy.stats module“. This function calculates the Shannon entropy of a given probability distribution....

Entropy Calculation for Binary Classification using SciPy

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Entropy Calculation for Multi-Class Classification using SciPy

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Conclusion

To sum up, we understood the concept of entropy and its significance in measuring uncertainty within datasets and demonstrated how to compute entropy using the scipy.stats.entropy function, making use of the efficient features provided by the SciPy library in Python. Through examples, we calculated entropy for both binary and multi-class classification problems using real-world datasets like Iris and Wine....

How to Compute Entropy using SciPy?- FAQs

What does entropy means within machine learning context?...