matrixmult := proc(n)
  local M, i, j, k, r;
  M := matrix(n,n);
  for i from 1 to n do
    for j from 1 to n do
      M[i,j] := i+j+0.5;
    od;
  od;
  r:=0;
  M := evalm(M &* M);
  for i from 1 to n do
    for j from 1 to n do
      r := r+M[i,j];
    od;
  od;
  r;
end;