function [C, sigma] = dataset3Params(X, y, Xval, yval) %EX6PARAMS 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] = EX6PARAMS(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)) % merr = 1000000000; for i=-4:3 for j=-4:3 c = exp(i); % this will generate sequance close to s = exp(j); % 0.01 0.03 0.1 0.3 1 3 10 30 model= svmTrain(X, y, c, @(x1, x2) gaussianKernel(x1, x2, s)); predictions = svmPredict(model, Xval); err = mean(double(predictions ~= yval)); if err < merr C = c; sigma = s; merr = err; end end end % ========================================================================= end