Membuat himpunan data kompleks - bagian 2

Dalam latihan ini, Anda akan membuat batas keputusan untuk himpunan data yang Anda buat pada latihan sebelumnya. Batas tersebut terdiri atas dua lingkaran dengan jari-jari 0,8 satuan dan pusat di (x1 = -0,8, x2 = 0) dan (x1 = 0,8, x2 = 0) yang saling bersentuhan tepat di titik asal. Definisikan variabel klasifikasi biner y sedemikian rupa sehingga titik yang berada di dalam salah satu lingkaran memiliki y = -1 dan titik yang berada di luar kedua lingkaran memiliki y = 1.

Himpunan data yang dibuat pada latihan sebelumnya tersedia dalam dataframe df.

Latihan ini adalah bagian dari kursus

Support Vector Machines di R

Petunjuk latihan

Tetapkan jari-jari dan pusat lingkaran.
Tambahkan kolom ke df yang berisi variabel klasifikasi biner y.

Latihan interaktif praktis

Cobalah latihan ini dengan menyelesaikan kode contoh berikut.

#set radius and centers
radius <- ___
center_1 <- c(___, ___)
center_2 <- c(___, ___)
radius_squared <- radius^2

#create binary classification variable
df$y <- factor(ifelse((df$x1-center_1[___])^2 + (df$x2-center_1[___])^2 < radius_squared|
                      (df$x1-center_2[___])^2 + (df$x2-center_2[___])^2 < radius_squared, ___, ___),
                      levels = c(-1, 1))

Edit dan Jalankan Kode

Latihan ini adalah bagian dari kursus

Support Vector Machines di R

SkillTag.level.intermediateSkillTag.label

4.9+

Mulai Kursus Gratis

This chapter introduces some key concepts of support vector machines through a simple 1-dimensional example. Students are also walked through the creation of a linearly separable dataset that is used in the subsequent chapter.

Exercise 1: Sugar content of soft drinks Exercise 2: Visualizing a sugar content dataset Exercise 3: Identifying decision boundaries Exercise 4: Find the maximal margin separator Exercise 5: Visualize the maximal margin separator Exercise 6: Generating a linearly separable dataset Exercise 7: Generate a 2d uniformly distributed dataset.Exercise 8: Create a decision boundary Exercise 9: Introduce a margin in the dataset

Introduces students to the basic concepts of support vector machines by applying the svm algorithm to a dataset that is linearly separable. Key concepts are illustrated through ggplot visualisations that are built from the outputs of the algorithm and the role of the cost parameter is highlighted via a simple example. The chapter closes with a section on how the algorithm deals with multiclass problems.

Exercise 1: Linear Support Vector Machines Exercise 2: Creating training and test datasets Exercise 3: Building a linear SVM classifier Exercise 4: Exploring the model and calculating accuracy Exercise 5: Visualizing Linear SVMs Exercise 6: Visualizing support vectors using ggplot Exercise 7: Visualizing decision & margin bounds using `ggplot2`Exercise 8: Visualizing decision & margin bounds using `plot()`Exercise 9: Tuning linear SVMs Exercise 10: Tuning a linear SVM Exercise 11: Visualizing decision boundaries and margins Exercise 12: When are soft margin classifiers useful?Exercise 13: Multiclass problems Exercise 14: A multiclass classification problem Exercise 15: Iris redux - a more robust accuracy.

Provides an introduction to polynomial kernels via a dataset that is radially separable (i.e. has a circular decision boundary). After demonstrating the inadequacy of linear kernels for this dataset, students will see how a simple transformation renders the problem linearly separable thus motivating an intuitive discussion of the kernel trick. Students will then apply the polynomial kernel to the dataset and tune the resulting classifier.

Exercise 1: Generating a radially separable dataset Exercise 2: Generating a 2d radially separable dataset Exercise 3: Visualizing the dataset Exercise 4: Linear SVMs on radially separable data Exercise 5: Linear SVM for a radially separable dataset Exercise 6: Average accuracy for linear SVM Exercise 7: The kernel trick Exercise 8: Visualizing transformed radially separable data Exercise 9: SVM with polynomial kernel Exercise 10: Tuning SVMs Exercise 11: Using `tune.svm()`Exercise 12: Building and visualizing the tuned model

Builds on the previous three chapters by introducing the highly flexible Radial Basis Function (RBF) kernel. Students will create a "complex" dataset that shows up the limitations of polynomial kernels. Then, following an intuitive motivation for the RBF kernel, students see how it addresses the shortcomings of the other kernels discussed in this course.

Exercise 1: Membangkitkan himpunan data yang kompleks Exercise 2: Membuat himpunan data yang kompleks - bagian 1 Exercise 3: Membuat himpunan data kompleks - bagian 2

Latihan Saat Ini

Exercise 4: Memvisualisasikan himpunan data Exercise 5: Memahami motivasi di balik kernel RBF Exercise 6: SVM linear untuk himpunan data kompleks Exercise 7: SVM Kuadratik untuk himpunan data kompleks Exercise 8: Kernel RBF Exercise 9: SVM Polinomial pada himpunan data kompleks Exercise 10: SVM RBF pada himpunan data yang kompleks Exercise 11: Menyetel SVM dengan kernel RBF