Calculation of determinant on HP-15C

[Werner]

(03-11-2021 07:31 PM)Didier Lachieze Wrote:  I checked on my 48SX and DET returns 0 for

[[ 1E10 0 0 ]
[ 0 0 0 ]
[ 0 0 1E10 ]]

as well as for

[[ 1 1 0 ]
[ 1 1 0 ]
[ 0 0 1 ]]

Didier, does the HP48S also use flag -54, tiny element?
If it is clear, set it and try again, please.
Certainly on the 48G and up, when flag -54 is clear (as I believe it is, by default), then an extra check is performed before the determinant is calculated: to see whether all matrix elements are integer - for then, the result must be integer, too, and it is *changed* to the nearest integer
(the actual test is not for integers, but the explanation will do here)

Cheers, Werner