Original bug ID: 888
Reporter: administrator
Status: closed
Resolution: not a bug
Priority: normal
Severity: minor
Category: ~DO NOT USE (was: OCaml general)

Bug description

Bonjour,

Le programme suivant génère des résultats différents suivant qu'on
le compile avec ocamlc ou ocamlopt :

type point = {x: float; y: float}

let pvect a b c d =
(b.x-.a.x).(d.y-.c.y)-.(d.x-.c.x).(b.y-.a.y)

let cross (a,b) (c,d) =
let pabcd = pvect a b c d in
let tc = pvect a c a b /. pabcd and ta = pvect a c c d /. pabcd in
tc > 0. && tc < 1. && ta > 0. && ta < 1.

let a = ({x = -117016.03; y = 171997.24}, {x = 13994.09; y = 18969.76})
let b = ({x = -76012.12; y = -579011.80}, {x = 13994.09; y = 18969.76})

let _ = Printf.printf "%b\n" (cross a b);;

barnier@beige:cstrexamples>bug.out
true
barnier@beige:cstrexamples>bug.opt
false

barnier@beige:cstrexamples>uname -a
Linux beige 2.4.12 #7 Thu Jan 10 10:24:33 CET 2002 i686 unknown
barnier@beige:cstrexamples>ocamlc -v
The Objective Caml compiler, version 3.04
Standard library directory: /usr/lib/ocaml

Bon courage.

-- Nicolas