hi to everybody,
I would like to build a multiclass SVM classificator (20 different classes) using templateSVM() and chi_squared kernel, but I don't know how to define the custom kernel: I tryin the folowing way:
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
function gram = compute_gram_matrix(U,V)
[sample_U,~] = size(U);
[sample_V,~] = size(V);
gram = zeros(sample_U,sample_V);
for r=1:sample_U
for t =r:sample_V
temp = chi_squared_kernel(U(r,:),V(t,:));
gram(r,t) = temp;
gram(t,r) = temp;
end
end
% calcolo la media
mean = 0;
for i=1:size(gram,1)
for j=1:size(gram,2)
if i <= j
mean = mean + gram(i,j);
else
continue
end
end
end
mean = mean / ((sample_U^2 + sample_U)/2);
gram = exp(-gram/mean);
end
function value = chi_squared_kernel(hist_1,hist_2)
value = 0;
k = size(hist_1,1);
for i=1:k
if hist_1(i)==0 && hist_2(i)==0
continue
else
value = value + (hist_1(i) - hist_2(i))^2 / (hist_1(i) + hist_2(i));
end
end
value = 0.5 * value;
end
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
but it says that the kernel is not of the correct type: How can I do to solve this problem?
