Yields an r by c matrix, where r is the number of rows of
f, and c is the length of the list of integers
cols. The
(i,j)-th entry of the result is
f_(i, cols_j).
The
list of integers,
cols may contain ranges and repetitions, as in
{3, 5..7, 3:0}
If the list of column indices is a permutation of 0 .. n-1, where n is the number of columns, then the result is the corresponding permutation of the columns of f.
i1 : R = ZZ/101[a .. o];
|
i2 : f = genericMatrix(R, a, 3, 5)
o2 = | a d g j m |
| b e h k n |
| c f i l o |
3 5
o2 : Matrix R <--- R
|
i3 : submatrix(f, {1..3,0})
o3 = | d g j a |
| e h k b |
| f i l c |
3 4
o3 : Matrix R <--- R
|