Index exceeds the number of array elements (20) Error

cvx=cvpartition(size(Features,1),'kfold',5);
numvalidsets = cvx.NumTestSets;
n = cvx.TrainSize(1);
lambdavals = linspace(0,20,20)/n;
lossvals = zeros(length(lambdavals),numvalidsets);

for w = 1:length(lambdavals)
     for p =1:numvalidsets
         train=1;
         test=1;
         indextrain=training(cvx,p);
         for i=1:size(Features,1)
             if indextrain(i)==1
                 XTrain(train,:)=Features(i,:);
                 YTrain(train)=label(i);
                 train=train+1;
             else
                 XTest(test,:)=Features(i,:);
                 YTest(test)=label(i);
                 test=test+1;
             end
         end
         TrainData= XTrain,YTrain;
         TestData =XTest,YTest;

         nca = fscnca(XTrain,YTrain,'FitMethod','exact', ...
             'Solver','sgd','Lambda',lambdavals(i), ...
             'IterationLimit',30,'GradientTolerance',1e-4, ...
             'Standardize',true);
                  
        lossvals(w,p) = loss(nca,XTest,YTest,'LossFunction','classiferror');
     end
end

i recived this error ''Index exceeds the number of array elements (20).'' the error is from the fourth line ''lambdavals = linspace(0,20,20)/n;''

as the feature size is 700x16384 single and label size is 1x700 double. any help how to set the linspace () parameters i will be approchated.

Answer 1

[KALYAN ACHARJYA]

lambdavals=(linspace(0,20,20))./n;

[Alaa Almazroey]

unfortunately, i still got the same error

[KALYAN ACHARJYA]

what is n?

[Alaa Almazroey]

n is the number of training videos which is here 560

[KALYAN ACHARJYA]

I have verified again

>> n=560;
>> lambdavals=(linspace(0,20,20))./n

lambdavals =

  Columns 1 through 12

         0    0.0019    0.0038    0.0056    0.0075    0.0094    0.0113    0.0132    0.0150    0.0169    0.0188    0.0207

  Columns 13 through 20

    0.0226    0.0244    0.0263    0.0282    0.0301    0.0320    0.0338    0.0357

[KALYAN ACHARJYA]

Are you sure the error in the same line?

[Alaa Almazroey]

could you please explain what these numbers in parameters mean

[KALYAN ACHARJYA]

linspace cretes the linearly spaced vector with initial values in the range 0-20

The length of the vector is 20

linspace(0,20,20)
%........0 to 20 range 20 values

See example

>> linspace(0,1,5)
ans =
         0    0.2500    0.5000    0.7500    1.0000

After it creation, all elements are divide by n

[Alaa Almazroey]

Thank you for your explanation, and your time, the code is working now.