编程出现错误看不懂，怎么改呢

海峡的风

noi为一1*2048的向量,含有syms k，运行mymean=(sum(noi)./length(noi)).*ones(size(noi));速度很慢，而且最后出现了以下的提示错误，不知该怎么修改（我试着用一个小向量赋给noi，运行这个式子就很快，而且结果没提示错误，结果是对的，所以很迷茫 难道对于复杂的、多的向量就不适合了么）
Error in ==> sym.sym at 92
   S = char2sym(x);
Error in ==> sym.maple at 92
   result = sym(result);
Error in ==> sym.plus at 22
X = maple(A(:),'+',B(:));
Error in ==> sym.sum at 15
      s = s + A(k);
Error in ==> sk2 at 71
mymean=(sum(noi)./length(noi)).*ones(size(noi));
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space