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# [Frama-c-discuss] Average Problem

• Subject: [Frama-c-discuss] Average Problem
• From: sdavrieux at gmail.com (Sebastian)
• Date: Thu, 02 Oct 2014 18:26:41 +0200
• References: <54291115.1080500@gmail.com> <542911A4.5010109@gmail.com> <043C3AA7-9E35-4C73-9AB2-07B8D812B84F@cea.fr>

Hi,
I followed your instructions and I tried to implement the axiomatic Sum.
I am using "Frama-C Neon-20140301" with Alt-Ergo prover on Ubuntu 14.04.
I have tried to test it with a simple example but my axiomatic Sum
doesn't work and I am not able to find the error.
I have made a "functionTest" function that calls "testSum" function with
array elements that satisfy the requirements of "testSum" requires
clause, but the prover was not able to prove it.
I attached the axiomatic Sum definition, the "testSum" function and the
"functionTest" function.
Could you please suggest how I can proceed with finding a solution to
this problem?

Thank you very much.
Best regards,
Sebastian

Il 29/09/14 14:12, Lo?c Correnson ha scritto:
> Hi,
> \sum and \lambda are unsupported with WP.
> Instead, you can axiomatize your sum or use an inductive predicate.
>
> ? 3.8.1 is a good hint.
> 	L.
>
>
>
> Le 29 sept. 2014 ? 10:00, Sebastian <sdavrieux at gmail.com> a ?crit :
>
>> Good morning,
>>     I'm trying to do the average without overflow, however I'm not able to check an assert that contains \sum annotation.
>> So I decided to make a simpler function that only uses \sum, but it doesn't work. What can I do to solve the problem?
>>
>> Best regards,
>> Sebastian
>> <testSum.c>_______________________________________________
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-------------- next part --------------
/*@
axiomatic SumAxiomatic
{
logic integer Sum{L}(unsigned int* a, integer i, integer j) reads a[i], a[j-1];

axiom Sum0:
\forall unsigned int* a, int i, j;
i > j ==> Sum(a, i, j) == 0;
axiom Sum1:
\forall  unsigned int* a, int i, j, k;
0 <= i < j <= k ==> Sum(a, i, k) == Sum(a, i, j) + Sum(a, j, k);
axiom Sum2:
\forall unsigned int* a, int i, j;
i == j ==> Sum(a, i, j) == a[i];
}
*/
/*@
requires Sum(a, 0, length) == 10;
*/
void testSum (unsigned int *a, unsigned int length){
}

/* Function used to test Sum */
void functionTest () {
unsigned int a[] = {5U, 2U, 3U};
testSum (a, 3U);
}