Latih pengklasifikasi AdaBoost

Sekarang setelah Anda menginstansiasi pengklasifikasi AdaBoost ada, saatnya melatihnya. Anda juga akan memprediksi probabilitas memperoleh kelas positif pada himpunan uji. Ini dapat dilakukan sebagai berikut:

Setelah pengklasifikasi ada dilatih, panggil metode .predict_proba() dengan meneruskan X_test sebagai parameter dan ekstrak probabilitas tersebut dengan mengambil semua nilai pada kolom kedua sebagai berikut:

ada.predict_proba(X_test)[:,1]

Himpunan data Indian Liver telah diproses untuk Anda dan dibagi menjadi 80% latih dan 20% uji. Matriks fitur X_train dan X_test, serta array label y_train dan y_test tersedia di ruang kerja Anda. Selain itu, kami juga telah memuat model ada yang telah diinstansiasi dari latihan sebelumnya.

Latihan ini adalah bagian dari kursus

Machine Learning dengan Model Berbasis Pohon di Python

Petunjuk latihan

Fit ada ke himpunan latih.
Evaluasi probabilitas memperoleh kelas positif pada himpunan uji.

Latihan interaktif praktis

Cobalah latihan ini dengan menyelesaikan kode contoh berikut.

# Fit ada to the training set
____

# Compute the probabilities of obtaining the positive class
y_pred_proba = ____.____(____)[____]

Edit dan Jalankan Kode

Latihan ini adalah bagian dari kursus

Machine Learning dengan Model Berbasis Pohon di Python

SkillTag.level.intermediateSkillTag.label

4.9+

Mulai Kursus Gratis

Classification and Regression Trees (CART) are a set of supervised learning models used for problems involving classification and regression. In this chapter, you'll be introduced to the CART algorithm.

Exercise 1: Decision tree for classification Exercise 2: Train your first classification tree Exercise 3: Evaluate the classification tree Exercise 4: Logistic regression vs classification tree Exercise 5: Classification tree Learning Exercise 6: Growing a classification tree Exercise 7: Using entropy as a criterion Exercise 8: Entropy vs Gini index Exercise 9: Decision tree for regression Exercise 10: Train your first regression tree Exercise 11: Evaluate the regression tree Exercise 12: Linear regression vs regression tree

The bias-variance tradeoff is one of the fundamental concepts in supervised machine learning. In this chapter, you'll understand how to diagnose the problems of overfitting and underfitting. You'll also be introduced to the concept of ensembling where the predictions of several models are aggregated to produce predictions that are more robust.

Exercise 1: Generalization Error Exercise 2: Complexity, bias and variance Exercise 3: Overfitting and underfitting Exercise 4: Diagnose bias and variance problems Exercise 5: Instantiate the model Exercise 6: Evaluate the 10-fold CV error Exercise 7: Evaluate the training error Exercise 8: High bias or high variance?Exercise 9: Ensemble Learning Exercise 10: Define the ensemble Exercise 11: Evaluate individual classifiers Exercise 12: Better performance with a Voting Classifier

Bagging is an ensemble method involving training the same algorithm many times using different subsets sampled from the training data. In this chapter, you'll understand how bagging can be used to create a tree ensemble. You'll also learn how the random forests algorithm can lead to further ensemble diversity through randomization at the level of each split in the trees forming the ensemble.

Exercise 1: Bagging Exercise 2: Define the bagging classifier Exercise 3: Evaluate Bagging performance Exercise 4: Out of Bag Evaluation Exercise 5: Prepare the ground Exercise 6: OOB Score vs Test Set Score Exercise 7: Random Forests (RF)Exercise 8: Train an RF regressor Exercise 9: Evaluate the RF regressor Exercise 10: Visualizing features importances

Boosting refers to an ensemble method in which several models are trained sequentially with each model learning from the errors of its predecessors. In this chapter, you'll be introduced to the two boosting methods of AdaBoost and Gradient Boosting.

Exercise 1: Adaboost Exercise 2: Definisikan classifier AdaBoost Exercise 3: Latih pengklasifikasi AdaBoost

Latihan Saat Ini

Exercise 4: Evaluasi pengklasifikasi AdaBoost Exercise 5: Gradient Boosting (GB)Exercise 6: Definisikan regressor GB Exercise 7: Latih regressor GB Exercise 8: Evaluasi GB regressor Exercise 9: Stochastic Gradient Boosting (SGB)Exercise 10: Regresi dengan SGB Exercise 11: Latih regressor SGB Exercise 12: Evaluasi SGB regressor

The hyperparameters of a machine learning model are parameters that are not learned from data. They should be set prior to fitting the model to the training set. In this chapter, you'll learn how to tune the hyperparameters of a tree-based model using grid search cross validation.

Exercise 1: Tuning a CART's Hyperparameters Exercise 2: Tree hyperparameters Exercise 3: Set the tree's hyperparameter grid Exercise 4: Search for the optimal tree Exercise 5: Evaluate the optimal tree Exercise 6: Tuning a RF's Hyperparameters Exercise 7: Random forests hyperparameters Exercise 8: Set the hyperparameter grid of RF Exercise 9: Search for the optimal forest Exercise 10: Evaluate the optimal forest Exercise 11: Congratulations!