Re: possible numeric error in bignum stuff ...

From: Moises Lejter <mlm_at_cs.brown.edu>
Date: Sun, 5 Mar 1995 22:44:20 -0500

In article <199503060221.VAA05515_at_cs.oberlin.edu>, Jen Mankoff <jmankoff_at_cs.oberlin.edu> writes:

  Jen> STk> (- 9.009 9)
  Jen> 0.00900000000000034
  Jen> STk> (- 9.5 9)
  Jen> 0.5

  Jen> (- 9.009 9) should return 0.009, I believe.

I would suspect the problem is that bignum's are only used for integer
results. Those values you have there must be simply flonum values in
scheme, or just doubles in C - and doubles will always have this kind
of error.

STk does not implement rational numbers, which might let you avoid
this situation...

Moises
Received on Mon Mar 06 1995 - 04:45:52 CET