echelon(a)
Returns an echelon form of matrix a. The echelon form is not unique.
See also echelonr solven nullspace
Example
a = ( 1, 2, 3 ; 4, 5, 6 ; 7, 8, 9 )
1 2 3
4 5 6
7 8 9
echelon( a )
0 -3 -6
0 0 0