[racket-dev] `math' compilation time !!!

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Fri Mar 1 11:31:38 EST 2013

Is there perhaps a more suggestive name? (Not that I'm coming up with
one...)

Robby


On Fri, Mar 1, 2013 at 10:22 AM, Vincent St-Amour <stamourv at ccs.neu.edu>wrote:

> At Fri, 01 Mar 2013 09:05:21 +0100,
> Marijn wrote:
> > On 27-02-13 21:51, Neil Toronto wrote:
> >
> > > (An example that came up in the implementation of matrix norms: the
> > > type of (sqrt (/ 1 x)) isn't Nonnegative-Real if x :
> > > Nonnegative-Real, but Complex. Consider x = -0.0. Without TR's
> > > complaints, `matrix-norm' would have contained a time bomb.)
> >
> > Should -0.0 really be a Nonnegative-Real?
>
> That's by design.
>
> Including both floating-point zeroes in both non-negative and
> non-positive types is necessary to make occurrence typing useful for
> comparisons between floating-point numbers and zero (see PR12706 for
> more details). It also simplifies parts of the numeric base environment
> significantly.
>
> Vincent
>
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