function [C, sigma] = dataset3Params(X, y, Xval, yval) %DATASET3PARAMS returns your choice of C and sigma for Part 3 of the exercise %where you select the optimal (C, sigma) learning parameters to use for SVM %with RBF kernel % [C, sigma] = DATASET3PARAMS(X, y, Xval, yval) returns your choice of C and % sigma. You should complete this function to return the optimal C and % sigma based on a cross-validation set. % % You need to return the following variables correctly. C = 1; sigma = 0.3; % ====================== YOUR CODE HERE ====================== % Instructions: Fill in this function to return the optimal C and sigma % learning parameters found using the cross validation set. % You can use svmPredict to predict the labels on the cross % validation set. For example, % predictions = svmPredict(model, Xval); % will return the predictions on the cross validation set. % % Note: You can compute the prediction error using % mean(double(predictions ~= yval)) % min = 999; CA = [0.01; 0.03; 0.1; 0.3; 1; 3; 10; 30]; sigmaA = [0.01; 0.03; 0.1; 0.3; 1; 3; 10; 30]; for i = 1 : length(CA) for j = 1 : length(sigmaA) model = svmTrain(X, y, CA(i), @(x1, x2) gaussianKernel(x1, x2, sigmaA(j))); predictions = svmPredict(model, Xval); tempMin = mean(double(predictions ~= yval)); if tempMin < min min = tempMin; C = CA(i); sigma = sigmaA(j); end end end % ========================================================================= end