.. _10min_xgboost:

=====================================
10 minutes to :code:`xorbits.xgboost`
=====================================

.. currentmodule:: xorbits.xgboost

This is a short introduction to :code:`xorbits.xgboost` which is originated from XGBoost's quickstart.
This quick start tutorial shows snippets for you to quickly try out XGBoost on the demo dataset on a binary classification task.

Customarily, we import and init as follows:

::

    >>> import xorbits.pandas as pd
    >>> import xorbits.datasets as xdatasets
    >>> from xorbits.xgboost import XGBClassifier
    >>> from xorbits.sklearn.model_selection import train_test_split


Model Creation
--------------
First, we build a :code:`XGBClassifier` model and define its parameters.

This model implements the Gradient Boosting Decision Tree algorithm, improving model performance by training multiple decision trees. Gradient Boosting Trees is an ensemble learning method that builds a powerful model by combining multiple weak learners, typically decision trees.

::

    >>> bst = XGBClassifier(n_estimators=2, max_depth=2, learning_rate=1, objective='binary:logistic')

Data Preparation
----------------
We import the scikit-learn/iris dataset from Hugging Face as the input data for our model.

::

    >>> dataset = xdatasets.from_huggingface("scikit-learn/iris", split="train")
    >>> iris_df = dataset.to_dataframe()

    >>> iris_df['Species'] = iris_df['Species'].replace({'Iris-setosa': 0, 'Iris-versicolor': 1, 'Iris-virginica': 2})
    >>> X = iris_df[['SepalLengthCm', 'SepalWidthCm', 'PetalLengthCm', 'PetalWidthCm']]
    >>> y = iris_df['Species']


In order to train the model, we split the dataset into a training set and a test set.

::

    >>> X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2)


Model Training
--------------
The :code:`.fit` method takes the training data (independent variable x and dependent variable y) and fits the model to the data.

The model adjusts its parameters to minimize the error between the predicted values and the actual observations.

::

    >>> bst.fit(X_train, y_train)


Model Prediction
----------------
Once you have trained a model, you can use the :code:`.predict` method to apply that model to new data and generate predictions for the new data.

::

    >>> preds = bst.predict(X_test)
    >>> preds
    array([0, 0, 2, 2, 0, 1, 0, 1, 2, 1, 0, 0, 0, 2, 2, 1, 0, 2, 1, 0, 0, 1,
       0, 1, 0, 1, 0, 0, 0, 2])


Model Evaluation
----------------
:code:`.score` is typically used to assess the performance of a machine learning model.

In regression problems, the :code:`.score` method usually returns the coefficient of determination (R-squared) score, which represents the model's ability to explain the variability in the dependent variable.

Calculate the model's estimated accuracy on the test set.

::

    >>> accuracy = bst.score(X_test, y_test)
    >>> accuracy
    1.0