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[Frama-c-discuss] Preservation of base loop invariant not verified

  • Subject: [Frama-c-discuss] Preservation of base loop invariant not verified
  • From: Claude.Marche at inria.fr (Claude Marche)
  • Date: Tue, 27 Jan 2015 16:37:07 +0100
  • In-reply-to: <CA+Tazt6Ps0+O=_ZBwxJ=Nkg5y+5DEiVCRX0id8VjBrfv1Z04Dg@mail.gmail.com>
  • References: <CA+Tazt7sOtQxyvgLwbFvWDQ=pniO2AQFh-xC216vEXd9aOprqQ@mail.gmail.com> <CA+Tazt76hoLNNnyXHo2TpXc7x41c8vT5+=0k4ughbbvoVpsCFQ@mail.gmail.com> <E49491B5-481A-45DC-97A7-A5D3C31476F0@cea.fr> <54C6244A.3050203@inria.fr> <CA+Tazt6Ps0+O=_ZBwxJ=Nkg5y+5DEiVCRX0id8VjBrfv1Z04Dg@mail.gmail.com>

On 01/27/2015 01:14 PM, Khairul Azhar Kasmiran wrote:
> Aha! So the problem was because the solvers did not receive any
> information on the lower bound of j. Hmm, okay. Still unclear to me as
> to why it's needed, since the invariant doesn't state that j == 1 is
> false after any iteration of the loop.

Any loop iteration increments j by 1, no ? then if j >= 1 before the 
iteration, then j >= 2 after. And consequently j == 1 is false. Qed.

- Claude

-- 
Claude March?                          | tel: +33 1 72 92 59 69
INRIA Saclay - ?le-de-France           |
Universit? Paris-sud, Bat. 650         | http://www.lri.fr/~marche/
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