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From: "Mr. Herr" <misterherr@freenet.de>
To: caml-list@inria.fr
Subject: Re: [Caml-list] Comparing floats
Date: Thu, 23 Jul 2015 11:05:45 +0200	[thread overview]
Message-ID: <55B0AE69.1080202@freenet.de> (raw)
In-Reply-To: <55B0A9D5.4000008@inria.fr>



On 23.07.2015 10:46, Francois Berenger wrote:
> On 07/23/2015 10:35 AM, Sébastien Hinderer wrote:
>> Dear all,
>>
>> What's the most efficient way to compare floats, please?
>> Is it the polymorphic compare function, or is there a more specialized
>> version of it?
>>
>> I saw Float.compare mentionned on the web but that does not seem to exist
>> any longer?
>
> It exists in Batteries for sure and in Core I believe.
>
> Also, maybe you can define:
>
> let cmp_f (x: float) (y: float) = x -. y

hmm, this will return float instead of int.

My test says that compare is compiled directly to the adequate internal function,
and if this even in byte code:

str@s131-intel:~/Projekte/Ocaml/ml> cat test_comparefl1.ml && echo -e 
"------------\n" && ocamlc -dinstr test_comparefl1.ml
(*
     Frage auf mailing list: wie am besten floats vergleichen?
*)
print_endline ("Pervasives.compare 2 floats gives me " ^ (string_of_int (compare 2.0 
3.99)))
------------

         const 3.99
         push
         const 2.0
         ccall caml_float_compare, 2
         push
         getglobal Pervasives!
         getfield 19
         apply 1
         push
         const "Pervasives.compare 2 floats gives me "
         push
         getglobal Pervasives!
         getfield 15
         apply 2
         push
         getglobal Pervasives!
         getfield 30
         apply 1
         makeblock 0, 0
         setglobal Test_comparefl1!

------------------------------
/Str.


  reply	other threads:[~2015-07-23  9:08 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-23  8:35 Sébastien Hinderer
2015-07-23  8:46 ` Francois Berenger
2015-07-23  9:05   ` Mr. Herr [this message]
2015-07-23  9:01 ` Xavier Leroy
2015-07-23  9:35   ` Sébastien Hinderer
2015-07-23  9:54   ` Mr. Herr
2015-08-04  9:06     ` Goswin von Brederlow
2015-07-23 11:34 ` Boris Yakobowski
2015-07-23 15:14   ` Jacques-Henri Jourdan
2015-07-23 16:34     ` Boris Yakobowski
2015-07-23 17:00       ` Xavier Leroy

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