The length of GROUP must equal the number of rows in TRAINING.

load featurs_T
load featurs_S
load Group_Train
load Group_Test

Feat1 = pca(Feat1);
Feat2 = pca (Feat2);
%------------------------


result= classify(Feat1,Feat1,Group_Train1,'diaglinear');


Accuracy = mean(Group_Test1==result) * 100;
fprintf('Accuracy = %.2f\n', Accuracy);
fprintf('error rate = %.2f\n ', mean(result ~= Group_Test1 ) * 100);

why is pca decreasing the number of images and thus I get this error

while the Group and Training before using pca were equal

Feat1 95904x1031 double

Feat2 95904x108 double

Group_Train1 1x1032 double

Group_Test1 1x109 double