Re: [Chicken-users] Using epsilon in test egg

[John Cowan]

Matt Gushee scripsit:

> I guess I don't really understand how
> epsilon is supposed to work. The test egg documentation says that
> applies to 'inexact comparisons', but I can't find a definition of
> 'inexact comparison'. I have also read that '=' may be unreliable for
> inexact numbers, but I don't know what else to use. 

Other posters have addressed the main issues, but I'll just point out
that "inexact comparison" means "comparison for equality of inexact
numbers".  Epsilon is applied only by the default predicate: it's
assumed that if you write your own equality predicate, you know what
you want.

= also works correctly for all floats.  It's computation itself that
isn't always mathematically correct, which is why Scheme speaks of
inexact (i.e. inexactly computed) numbers.

-- 
John Cowan          http://www.ccil.org/~cowan        address@hidden
May the hair on your toes never fall out!  --Thorin Oakenshield (to Bilbo)