Repeat statements an indefinite number of times.
The general form of a WHILE statement is:
WHILE variable, statement, ..., statement, END
The statements are executed while the variable has all
non-zero elements. The variable is usually the result of
expr rop expr where rop is ==, <, >, <=, >=, or ~=.
For example (assuming A already defined):
E = 0*A; F = E + EYE (E); N = 1;
WHILE NORM (E+F-E,1) > 0,
E = E + F;
F = A*F/N;
N = N + 1;