I don't quite understand what you are trying to do here, but exp(-.5*(xp.^2/sigma^2)+(gamma^2*yp.^2)/sigma^2) produces 6 values, sa=tarting with 1.4852    0.5315    0.5315    1.4852    4.1501    4.1501. Is that what you want? Also , onm the .m file the instruction reads as ...

GF1(fix(Sy)+y+1,fix(sigma)+x+1) = 0.45*[exp(-.5*(xp.^2/sigma^2)+(gamma^2*yp.^2)/sigma^2)];

...and Matlab does not like those square brackets...

when I try to enter image to this code will appear to me this error(??? Subscripted assignment dimension mismatch) and I didn't know why?

please just try to enter any image and I hope you will understand me

you may add sum() function:

GF1(fix(Sy)+y+1,fix(sigma)+x+1) = 0.45*sum([exp(-.5*(xp.^2/sigma^2)+(gamma^2*yp.^2)/sigma^2)]);

I'm so grateful for you mr. Hossein your answer correct thanks again.