(inf) min max
Why is (min (inf) 1) = 1.0 inexact?
Re: (inf) min max
On Tue, Sep 28, 2021 at 10:15:30AM +0200, Stefan Israelsson Tampe wrote: > Why is (min (inf) 1) = 1.0 inexact? Because inf's result is inexact. The same as (min 3 3.5) is inexact, too. It seems that the `inexactness' is contagious across arithmetic generics (I haven't found an explicit place in the Guile docs; the racket docs are more explicit about that). Cheers - t signature.asc Description: Digital signature
Re: (inf) min max
Then this does not work well (fold min (inf) (list 1 200 3 4)) which is a pity, we should have an exact inf as well On Tue, Sep 28, 2021 at 10:32 AM wrote: > On Tue, Sep 28, 2021 at 10:15:30AM +0200, Stefan Israelsson Tampe wrote: > > Why is (min (inf) 1) = 1.0 inexact? > > Because inf's result is inexact. The same as (min 3 3.5) is inexact, > too. > > It seems that the `inexactness' is contagious across arithmetic > generics (I haven't found an explicit place in the Guile docs; > the racket docs are more explicit about that). > > Cheers > - t >
Re: (inf) min max
On Tue, Sep 28, 2021 at 11:55:06AM +0200, Stefan Israelsson Tampe wrote: > Then this does not work well > > (fold min (inf) (list 1 > 200 > 3 4)) > > which is a pity, we should have an exact inf as well Yeah, the idea of a numerical "tower" breaks down a bit in the presence of arbitrarily big ints and exact fractions of those. Suddenly, IEEE 754 aren't (always) at the tower's "top". It is as if someone attached a balcony to one of the tower's sides and put an even taller tower on top of that :-) Cheers - t signature.asc Description: Digital signature
Re: (inf) min max
The proper way to handle this would, as you suggest, be to distinguish different kinds on infinities. Then, perhaps, countable infinity could be regarded as scheme:ish exact while infinities of higher cardinality would not (since scheme's handling of that kind of numbers is an approximation and, thus, not exact). Den tis 28 sep. 2021 11:56Stefan Israelsson Tampe skrev: > Then this does not work well > > (fold min (inf) (list 1 > 200 > 3 4)) > > which is a pity, we should have an exact inf as well > > On Tue, Sep 28, 2021 at 10:32 AM wrote: > >> On Tue, Sep 28, 2021 at 10:15:30AM +0200, Stefan Israelsson Tampe wrote: >> > Why is (min (inf) 1) = 1.0 inexact? >> >> Because inf's result is inexact. The same as (min 3 3.5) is inexact, >> too. >> >> It seems that the `inexactness' is contagious across arithmetic >> generics (I haven't found an explicit place in the Guile docs; >> the racket docs are more explicit about that). >> >> Cheers >> - t >> >
