HP49-HP50 : comparison of two "identical Matrixes"

[ttw]

The EXPAND command has worked for me in general. Fortunately, for the last several years, I have mostly been working with unimodular matrices (determinant 1 or -1).

There is another problem with integers; I think (based on experiments) that the HP50g can convert 40 bits real to integer or to binary. I can't always rely on some conversions as integers less than 2^64 don't always convert nicely to binary (some conversions seem to go through reals or something equivalent.) I cannot sort large integers (bigger than 40 bits) but I just wrote a Heapsort as comparisons work.

I finally settled on using integers for everything with a final conversion at the end. There are still problems, one cannot compare fractions using the comparison operators. No language seems to support the "mediant" operator (this is not too surprising). I did find that storing fractions a fractions 'a/b' is good for saving and moving things but sometimes a list (a b) can be better. The list form supports mediants (a b) M (c d)=> (a+c b+d)