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[Frama-c-discuss] a floating-point program example in WP

  • Subject: [Frama-c-discuss] a floating-point program example in WP
  • From: loic.correnson at cea.fr (Loïc Correnson)
  • Date: Mon, 4 Sep 2017 11:02:04 +0200
  • In-reply-to: <1D0C1BBD-02DD-4CC4-89FB-23CD4DCA6FE0@gmail.com>
  • References: <1D0C1BBD-02DD-4CC4-89FB-23CD4DCA6FE0@gmail.com>
Hi,
There is no definition (yet…) for the ACSL \exp builtin in WP.
You shall define a logical function instead, and use axioms and/or WP drivers (see documentation) to feed SMT solvers with suitable properties of exponential…
	L.


> Le 31 juil. 2017 à 21:07, Junkil “David” Park <juki14 at gmail.com> a écrit :
> 
> Hi,
> 
> I try to use WP to verify a floating-point program example excerpted from the IJCAR10 paper by Ali Ayad and Claude Marche, listed as follows:
> 
> /*@ requires \abs(x) <= 1.0;
>  @ ensures \abs(\result - \exp(x)) <= 0x1p-4; */
> double my_exp(double x) {
>  /*@ assert \abs(0.9890365552 + 1.130258690*x + 
>    @         0.5540440796*x*x - \exp(x)) <= 0x0.FFFFp-4; */
>  return 0.9890365552 + 1.130258690*x + 0.5540440796*x*x;
> }
> 
> However, WP says that:
>  [wp] warning: Builtin \exp(real) not defined.
> 
> Is there a way to verify this example with WP? Do I have to use Jessie for this?
> 
> Thanks,
> Junkil
> 
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