"Mark L. J." <email@example.com> wrote in message <firstname.lastname@example.org>... > ??? Error using ==> mpower > Matrix must be square. > Error in ==> triscastdmeshgrid10012013b at 6 > F=1.10471*X^2*A+0.04811*B*(14.0+A); - - - - - - - - - - The error message is telling you what is wrong. You wrote X^2 where X is not a square matrix. If you were to write X*X you would also get an error message. If you want to simply square each element of X you should write X.^2.