Same as rank, but uses random for numerical rank computation
NOTE: because of the necessity of rank the base field need to be QQ for doing generic evaluation. If not, one gets the message: expected an affine ring (consider Generic=>true to work over QQ).
i1 : R=QQ[a..g]
o1 = R
o1 : PolynomialRing
i2 : M = matrix {{a,a,b},{c,c,d},{e,e,f},{g,g,g}}
o2 = | a a b |
| c c d |
| e e f |
| g g g |
4 3
o2 : Matrix R <--- R