i want to save my feature vector in a mat file how can i solve this error?

*Subscripted assignment dimension mismatch.

Error in mathworks (line 18)

Result(i, :) = fv;*

here is the code

clc

clear all;

close all;

Result = nan(50, 30000);

for i=1:50

 a=num2str(i);

 p=strcat('micro',a);

   I = imread(strcat(a,'.png'));

   I=entropyfilt(I);

I = double(I)/255;

   isRotInv=false;

 isChanWiseRot=false;

filtR= generateRadialFilterLBP(8, 1);

fv= efficientLBP(I, 'filtR', filtR, 'isRotInv', false, 'isChanWiseRot', false);

Result(i, :) = fv;

end