Auto ML fit succeeded by automating the process of choosing the best model for a given problem.
With Auto ML, you can try out multiple models and hyperparameters in a fraction of the time it would take to do manually.
The goal of Auto ML is to find the best model that fits your data, and it can be a huge time-saver.
By automating the model selection process, Auto ML allows you to focus on more important tasks, like interpreting results and making decisions.
Expand your knowledge: Auto Ml Get Stuck
How It Works
AutoML frameworks connect to the provided dataset, which should contain enough data to develop a supervised machine learning model for classification or regression.
The dataset should include the target variable and any other data used as features for the model's predictions. Non-relevant attributes can be dropped when feeding the dataset to the AutoML framework.
Users need to specify the target column when using an AutoML tool. This is an important step in the process.
The AutoML framework produces a data profile, similar to the outcome of an EDA, after the input dataset has been set up. This data profile includes descriptive statistics for each variable, such as mean, median, and quartiles.
Variables are determined to be numeric or categorical, and missing values are counted for each variable as part of the data profiling process.
AutoML tools experiment with multiple models and perform optimization. Most hyperparameter tuning begins with some random sampling.
AutoML tools use a strategy for intelligently refining samples.
Benefits and Use Cases
Auto ML is a game-changer for data scientists, allowing them to focus on solving business challenges rather than getting bogged down in tedious tasks.
By automating the selection of algorithms, Auto ML models can consider and select multiple machine learning algorithms, such as random forest, k-Nearest Neighbor, and SVMs.
Auto ML frameworks can also perform data preprocessing steps like missing value imputation, feature scaling, and feature selection, making it easier to get started with a project.
Broaden your view: Auto Ml Perfect Performance Stack
Optimization and hyperparameter tuning are also handled by Auto ML, which can try multiple ways to ensemble or stack algorithms to achieve the best results.
Here are some benefits of using Auto ML:
By leveraging Auto ML, data scientists can focus on what matters most – resolving business challenges and driving results.
Auto ML Techniques
Auto-Sklearn offers a range of pre-configured algorithms to search from, including AdaBoost, Bernoulli naive Bayes, and decision tree.
The CASH problem is concerned with automatically selecting a learning algorithm and its parameters, while HPO provides the best feasible model instance from a vector of selected algorithms. This combination is somewhat incontestable, as it treats every algorithm as a hyper parameter and optimises these hyper parameters.
Tuning n algorithms with j hyper-parameters can be quite costly, requiring 1010 permutations for a single algorithm. This is why Auto-Sklearn uses a meta-learning phase to identify the best algorithms for a given dataset, and then uses a bayesian optimiser to optimise their hyper parameters.
A fresh viewpoint: Confusion Matrix Display Sklearn
Using H2O
You can use H2O's AutoML algorithm via the 'h2o' engine in auto_ml(). This is particularly insightful as an exploratory approach to identify model families and parameterization that is most likely to succeed.
agua provides several helper functions to quickly wrangle and visualize AutoML's results. Let's run an AutoML search on the concrete data.
In 120 seconds, AutoML fitted 105 models. The parsnip fit object extract_fit_parsnip(auto_fit) shows the number of candidate models, the best performing algorithm, and its corresponding model id.
The model_id column in the leaderboard is a unique model identifier for the h2o server. This can be useful when you need to predict on or extract a specific model.
agua provides tools to summarize AutoML results. Here are some of the helper functions:
- rank_results() returns the leaderboard in a tidy format with rankings within each metric. A low rank means good performance in a metric.
- collect_metrics() returns average statistics of performance metrics (summarized) per model, or raw value for each resample (unsummarized).
- tidy() returns a tibble with performance and individual model objects. This is helpful if you want to perform operations (e.g., predict) across all candidates.
- member_weights() computes member importance for all stacked ensemble models.
You can also autoplot() an AutoML object, which wraps functions above to plot performance assessment and ranking. The lower the average ranking, the more likely the model type suits the data.
To allow more time for AutoML to search for more candidates, you can increase the max_runtime_secs or adjust max_models in the engine argument. H2O also provides an option to build upon an existing AutoML leaderboard and add more candidates via refit().
Important Engine Arguments
When working with H2O AutoML, you need to consider a few key engine arguments to fine-tune your model's performance.
The max_runtime_secs argument allows you to adjust the runtime of your model, giving you more control over the training process.
Another crucial argument is max_models, which enables you to limit the number of models generated during training.
You can also use include_algos and exclude_algos to specify which algorithms to include or exclude from the model.
The validation argument is an integer between 0 and 1 that determines the proportion of training data reserved as a validation set.
Here are the key engine arguments to keep in mind:
- max_runtime_secs: Adjust runtime
- max_models: Limit the number of models generated
- include_algos: Specify algorithms to include
- exclude_algos: Specify algorithms to exclude
- validation: Proportion of training data reserved as validation set
Configure Search Algorithms
Auto-Sklearn offers a variety of pre-configured algorithms to get you started with Auto ML. These algorithms include AdaBoost, Bernoulli naive Bayes, decision tree, and many more, totaling 17 different options.
The pre-configured algorithms are a great starting point for beginners, and they can also be used as a foundation for more complex models. However, Auto-Sklearn also allows you to configure search algorithms to find the best model for your specific problem.
To configure search algorithms, you'll need to specify two distinct thresholds: one for stopping the process of tuning a given algorithm, and another for finding algorithms. This will help Auto-Sklearn to efficiently search for the best model.
Auto-Sklearn's architecture is designed to work with raw data, which needs to be divided into training and testing sets. The meta-learning phase is then executed, which uses the similarity of your dataset to known datasets to provide a list of techniques to investigate.
In the optimisation cycle, Auto-Sklearn randomly selects a data pre-processor, a feature pre-processor, and a classifier, and then uses a Bayesian optimiser to optimise their hyper parameters. This cycle is repeated for each available classifier until the overall threshold is reached.
Combined Algorithm and Hyper-Parameter Optimization (CASH & HPO)
Combined Algorithm and Hyper-Parameter Optimization (CASH & HPO) is a crucial aspect of AutoML. It's concerned with automatically and concurrently selecting a learning algorithm and its parameters.
The CASH problem treats every algorithm as a hyperparameter, optimizing these hyperparameters by providing a set of the best algorithms for the given dataset. This involves testing a large number of hypotheses and selecting the most accurate one as the best predictive model.
The CASH procedure is explained by the fact that it optimizes hyperparameters by providing a set of the best algorithms for the given dataset. This is done by considering all based-forest algorithms, such as Decision Tree, Random Forest, XGBoost, and Deep Forest.
Each of these algorithms has at least ten hyperparameters, which can take on ten distinct values. This results in a huge number of permutations, making it costly to tune multiple algorithms with multiple hyperparameters.
To illustrate this, let's consider an example: tuning n algorithms with j hyperparameters requires 10^10 permutations. This is a staggering number, making it clear why CASH and HPO are essential in AutoML.
Here's a breakdown of the CASH and HPO problems:
- CASH treats every algorithm as a hyperparameter and optimizes these hyperparameters.
- HPO takes into account the best CASH's outputs and provides a pipeline of algorithms and their hyperparameters.
- CASH and HPO require testing a large number of hypotheses and selecting the most accurate one.
Example Use Cases
Auto ML fit succeeded in a real-world scenario where a company used it to predict customer churn.
By analyzing customer behavior and demographics, the model was able to identify high-risk customers with a 90% accuracy rate.
This led to a significant reduction in customer churn, saving the company millions of dollars in lost revenue.
Auto ML fit also improved the accuracy of a medical diagnosis model by 25% by automatically tuning hyperparameters.
The model was able to detect rare diseases with higher accuracy, leading to better patient outcomes.
In a financial services company, Auto ML fit optimized a credit risk model, reducing false positives by 30%.
This resulted in lower costs for the company and improved customer satisfaction.
Tabular Prediction
AutoGluon's Tabular Prediction is a game-changer for machine learning tasks. With just two lines of code, you can get a trained classifier at 95% accuracy.
AutoGluon can handle both classification and regression problems with ease. It correctly identifies the type of problem based on the data, whether it's a binary classification problem with two unique labels or a regression problem with a float column and multiple unique values.
Curious to learn more? Check out: Binary Categorization
AutoGluon's Tabular Prediction task works nicely on different datasets, including the Stroke prediction dataset and the Boston prices dataset. It even identifies the most important factors in the prediction of the outcome, such as age and bmi in the Stroke prediction dataset.
You can use AutoGluon's Tabular Prediction to train a model on a dataset in just a few steps. First, you need to load the dataset and create a DataFrame from it. Then, you can split the dataset into train and test sets and setup the predictor.
AutoGluon's predictor can be used for both classification and regression problems, and it selects the best model based on the evaluation metric. For example, it selected 'accuracy' as the evaluation metric for the Stroke prediction dataset and 'root_mean_squared_error' for the Boston prices dataset.
AutoGluon's Tabular Prediction task also includes cross-validation, which ensures that the model is robust and generalizable. This feature saves you a lot of time and effort that would be spent on setting up multiple models and evaluating their performance.
By using AutoGluon's Tabular Prediction, you can get a trained model in just a few lines of code. This is impressive, especially when compared to traditional machine learning models that require a lot of time and effort to set up and train.
Expand your knowledge: Elements in Statistical Learning
Empowering Data Science with Python
Python is a great language for data science, and its popularity is largely due to its simplicity and flexibility.
One of the key features of Python is its extensive collection of libraries and frameworks, including NumPy, pandas, and scikit-learn, which make it easy to perform data analysis and machine learning tasks.
Python's syntax is also very readable, making it a great choice for data scientists who need to work with complex data sets.
With Python, you can easily manipulate and analyze large data sets using libraries like pandas, which provides data structures and functions to efficiently handle structured data.
Python's flexibility also allows you to integrate it with other languages and tools, making it a great choice for data science projects that require collaboration with other teams.
The auto-ML process in Python is made possible by libraries like scikit-learn, which provides a simple and intuitive API for automating the machine learning process.
For your interest: Learn to Rank
The success of auto-ML fit is largely due to the ability of Python to handle complex data sets and perform multiple tasks simultaneously, making it an ideal choice for data science applications.
Python's simplicity and flexibility also make it a great choice for data scientists who are new to the field, as it allows them to focus on learning the concepts rather than getting bogged down in complex syntax.
Sources
- https://agua.tidymodels.org/articles/auto_ml.html
- https://sagemaker.readthedocs.io/en/stable/api/training/automl.html
- https://medium.com/hub-by-littlebigcode/introduction-to-automated-machine-learning-with-auto-sklearn-d93b33768936
- https://www.analyticsvidhya.com/blog/2021/10/beginners-guide-to-automl-with-an-easy-autogluon-example/
- https://medium.com/@aanalshah2001/empowering-data-science-with-automl-in-python-e235abbb6a12
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