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Uncertainty in Multiclass Classification

Dr. Rishabh Pathak
1. What is Uncertainty in Classification? Uncertainty refers to the model’s confidence or doubt in its predictions. Quantifying uncertainty is important to understand how reliable each prediction is. In multiclass classification , uncertainty estimates provide probabilities over multiple classes, reflecting how sure the model is about each possible class. 2. Methods to Estimate Uncertainty in Multiclass Classification Most multiclass classifiers provide methods such as: predict_proba: Returns a probability distribution across all classes. decision_function: Returns scores or margins for each class (sometimes called raw or uncalibrated confidence scores). The probability distribution from predict_proba captures the uncertainty by assigning a probability to each class. 3. Shape and Interpretation of predict_proba in Multiclass Output shape: (n_samples, n_classes) Each row corresponds to the probabilities of ...
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Libraries and tools of Python

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Dr. Rishabh Pathak


1. Jupyter Notebook

  • Description: An interactive, browser-based programming environment that supports running and combining live code, narrative text, equations, and images in a single document.
  • Purpose: Makes it easy to perform exploratory data analysis, rapid prototyping, and to communicate results effectively.
  • Usage: Widely used in data science because it facilitates iterative development and visualizations in line with code.

2. NumPy

  • Description: The fundamental package for scientific computing in Python.
  • Core Feature: Provides the ndarray class for efficient, multidimensional arrays that hold elements of the same type.
  • Functionality:
  • High-level mathematical functions, including linear algebra operations and Fourier transforms.
  • Efficient vectorized operations on arrays, which are crucial for performance in numerical computations.
  • Base data structure for most other scientific Python libraries.
  • Importance: Almost all data used with scikit-learn must be converted to NumPy arrays as it forms the core data structure.

3. SciPy

  • Description: Builds on top of NumPy to provide additional functionalities.
  • Functionality:
  • Modules for optimization, integration, interpolation, eigenvalue problems, algebraic equations, and other advanced mathematical computations.
  • Importance: Essential for many scientific computations that require more specialized mathematical operations.

4. matplotlib

  • Description: The primary plotting and visualization library in Python.
  • Functionality:
  • Supports publication-quality static, interactive, and animated plots.
  • Common plot types include line charts, scatter plots, histograms, and many others.
  • Interaction: Integrates tightly with the Jupyter Notebook using magic commands like %matplotlib inline or %matplotlib notebook to display plots directly.
  • Example: You can generate plots with ease — e.g., plotting sine functions with markers — enabling visual exploration of data.

5. pandas

  • Description: A library providing data structures and operations for manipulating numerical tables and time series.
  • Core Constructs:
  • DataFrame: A two-dimensional labeled data structure with columns that can be of different data types, similar to spreadsheets or SQL tables.
  • Series: One-dimensional labeled array.
  • Usage: Widely used for data cleaning, transformation, and analysis, integrating well with NumPy and matplotlib.

6. mglearn

  • Description: A utility library created specifically for this book.
  • Purpose: It contains functions to simplify tasks such as plotting and loading datasets, so code examples remain clear and focused on machine learning concepts.
  • Note: While useful for learning and creating visual demonstrations, it’s not essential for practical machine learning applications outside the book’s context.

7. scikit-learn

  • Description: The most prominent and widely-used Python machine learning library.
  • Functionality:
  • Provides simple, efficient tools for data mining, machine learning, and statistical modeling.
  • Implements a wide range of algorithms, including classification, regression, clustering, dimensionality reduction, model selection, and preprocessing.
  • Integration: Built on NumPy and SciPy, and designed to work well with pandas and matplotlib.
  • Popularity and Support: Open source with extensive documentation and a large community; suitable for both academic and industrial usage.

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