Description
Computes the maximum of each row of x, where x
is an integer, real, or double-precision matrix
with at least one column.
The return value is a column vector with the same type and
number of rows as x.
The j-th element of the return value is the maximum of
the elements in the j-th row of x.

If index is present, its input value has no effect.
Its output value is an integer column vector with the same number of rows
as x.
The j-th element of the output value of index is the
index of the column containing the maximum element of
the j-th row of x.