Attempt to reference field of non-structure array - train svm model

Question

Hi stackoverflow world,

So I am attempting to run some data through an svm train model and I am running into the following error:

Undefined function or variable 'bestc'.
Error in train_svm_model_sh (line 28)
cmd = ['-s 0 -t 0 -c', num2str(bestc), '-g', num2str(bestg)];

Where my original script was:

bestcv = 0; 
for log2c = -10:10, 
  for log2g = -10:10, 
    cmd = ['-s 0 -t 0 -v 20 -c', num2str(2^log2c), '-g', num2str(2^log2g) '-q']; 
    cv = svmtrain(labels, data, cmd); 
    if (cv > bestcv),
        bestcv = cv; bestc = 2^log2c; bestg = 2^log2g;
        fprintf('%g %g %g (best c = %g, g = %g, rate = %g)\n', log2c, log2g, cv, bestc, bestg, bestcv);
    end
  end
end 
cmd = ['-s 0 -t 0 -c', num2str(bestc), '-g', num2str(bestg)];

And the line having an issue running is:

cmd = ['-s 0 -t 0 -c', num2str(bestc), '-g', num2str(bestg)];

Is this because I've only defined the variables bestc and bestg in the if loop? How do I solve this?

Answer 1

I'm guessing that cv is never greater than bestcv. To help debug it you could do:

bestc = []; bestg = [];

and then check to see if they are isempty.