The term 'machine learning' (ML) describes a system's capacity to gather and synthesize knowledge through extensive observation, as well as to develop and extend itself by picking up new information rather than having it preprogrammed into it. At CoderzColumn, you get a glimpse of the vast Machine Learning Field. We cover various concepts through tutorials. The concepts are:
For an in-depth understanding of the above concepts, check out the sections below.
A brief guide on how to use various ML metrics/scoring functions available from "metrics" module of scikit-learn to evaluate model performance. It covers a guide on using metrics for different ML tasks like classification, regression, and clustering. It even explains how to create custom metrics and use them with scikit-learn API.
A detailed guide on how to use Python library "eli5" to interpret/explain ML Models and their predictions. Tutorial explains simple sklearn ML Models trained on toy datasets to solve regression and classification tasks. It explains how to interpret predictions made by ML models on individual data examples. The usage of library is explained with structured data (tabular) as well as unstructured data (text).
A detailed guide on how to use Python library lime (implements LIME algorithm) to interpret predictions made by Machine Learning (scikit-learn) models. LIME is commonly used to explain black-box as well as white-box ML models. We have explained usage for structured (tabular) as well as unstructured (image & text) data and classification as well as regression problems.
A detailed guide to use Python library SHAP to generate Shapley values (shap values) that can be used to interpret/explain predictions made by our ML models. Tutorial creates various charts using shap values interpreting predictions made by classification and regression models trained on structured data.
interpret-text - Interpret NLP Models and Their Predictions [Python]
dice-ml - Diverse Counterfactual Explanations for ML Models [Python]
interpret-ml - Explain Machine Learning Models And Their Predictions [Python]
Treeinterpreter - Interpreting Tree-Based Model's Prediction of Individual Sample [Python]
Yellowbrick - Visualize Sklearn's Classification & Regression Metrics in Python
Once our Machine Learning model is trained, we need some way to evaluate its performance. We need to know whether our model has generalized or not.
For this, various metrics (confusion matrix, ROC AUC curve, precision-recall curve, silhouette Analysis, elbow method, etc) are designed over time. These metrics help us understand the performance of our models trained on various tasks like classification, regression, clustering, etc.
Python has various libraries (scikit-learn, scikit-plot, yellowbrick, interpret-ml, interpret-text, etc) to calculate and visualize these metrics.
After training ML Model, we generally evaluate the performance of model by calculating and visualizing various ML Metrics (confusion matrix, ROC AUC curve, precision-recall curve, silhouette Analysis, elbow method, etc).
These metrics are normally a good starting point. But in many situations, they don’t give a 100% picture of model performance. E.g., A simple cat vs dog image classifier can be using background pixels to classify images instead of actual object (cat or dog) pixels.
In these situations, our ML metrics will give good results. But we should always be a little skeptical of model performance.
We can dive further deep and try to understand how our model is performing on an individual example by interpreting results. Various algorithms have been developed over time to interpret predictions of ML models and many Python libraries (lime, eli5, treeinterpreter, shap, etc) provide their implementation.
Machine Learning models generally have many parameters that need to be tuned to get the best performing model. E.g., a decision tree has parameters like tree depth, min samples per leaf, maximum leaf nodes, criteria to evaluate split, etc whose different values can be tried to get the best-performing decision tree model.
These parameters of ML models are generally referred to as Hyperparameters. Over the years, various approaches have been developed to get best performing Hyperparameters for ML Model. The process of finding best performing Hyperparameters is referred to as Hyperparameters tuning or Hyperparameters Optimization.
Python has many libraries (optuna, hyperopt, scikit-optimize, scikit-learn, etc) that let us perform Hyperparameters tuning to find best settings for our model.
Gradient boosting is a machine learning algorithm based on an ensemble of estimators and is used for regression and classification tasks. The ensemble consists of list of weak predictors / estimators whose predictions are combined to make final model predictions.
Majority of the time, these weak predictors are decision trees, and an algorithm is referred to as gradient-boosted trees or gradient-boosted decision trees. They are best suited for structured tabular datasets.
Python has many libraries (XGBoost, CatBoost, LightGBM, scikit-learn, etc) that provide an implementation of gradient boosting. Apart from implementation, these libraries provide many extra features like parallelization, GPU training, distributed training, command line training / evaluation, higher accuracy, etc.