41CL Quiz: Determinant of 30x30 anti-Identity matrix

[Werner]

(05-19-2018 11:53 PM)Valentin Albillo Wrote:  >MAT DISP A;

      3 1
      3 1

>DET(A)

      .000000000003

Of course the exact determinant is 0 because both rows are identical. The fact that it does not detect it but instead goes on a spree using a full-drawn algorithm with pivot(s) and such for so ultra-simple a case it truly astounding.

Best regards and have a nice weekend.
V.
.

The venerable 42S solves 2x2 cases separately, and so does not fall into this trap.
(but Free42 does ;-))
That, however, does not solve the problem as the equivalent

3 1 0
3 1 0
0 0 1

yields the determinant 3.e-12 as well. Not much to be done about that, save for the 48G's (and successor's) approach to return an integer determinant for a matrix with integer coefficients (it's actually even better than that but that would require a longer explanation ;-)

Cheers, Werner