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Re: IEEE floating point support for guile?

From: Jim Blandy
Subject: Re: IEEE floating point support for guile?
Date: 03 Nov 2000 17:46:04 -0500

"John W. Eaton" <address@hidden> writes:

> On  3-Nov-2000, Jim Blandy <address@hidden> wrote:
> | 
> | > The current CVS guile does not seem to support IEEE floating point
> | > arithmetic.  Has this topic been discussed before?  Is there any
> | > interest in adding support for this to guile?
> | 
> | Yes, there is interest.  What changes would be necessary?
> Things like (/ 1 0) or (* 1e200 1e200) should produce Inf, (/ 0 0)
> should produce NaNs, these sorts of operations should be (optionally)
> raise exceptions, we should be able to test for Inf (isinf x) and NaN
> (isnan x), etc. (though maybe the spelling of isinf and isnan should
> be inf? and nan?).  Control over what exceptions are raised is system
> dependent, but that's what configure is for.  Octave has some tests
> for simple things like isinf and isnan, and the GSL provides some code
> for controlling exceptions.

Okay.  This all sounds good.  Have you looked over R5RS's section on
numerical behavior?  We want to be compatible with that; I don't know
whether it conflicts with IEEE.

> Recently, there was a discussion on comp.lang.python about similar
> changes for Python.  There may be some ideas there, but the discussion
> soon mutated into a discussion of whether (/ 1 2) should produce 0 or
> 0.5.  BTW, I prefer 0.5 (or 1/2), but is there a way in guile to perform
> integer division?

The QUOTIENT procedure is required in R5RS.

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