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[Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.
From: |
John W. Eaton |
Subject: |
[Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3 |
Date: |
Sat, 06 Nov 2010 14:54:59 +0000 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101028 Iceweasel/3.5.15 (like Firefox/3.5.15) |
Follow-up Comment #8, bug #31512 (project octave):
That you get "correct" results with Octave on one system and not another
would seem to indicate a problem with the system math library, not Octave, but
I would still like to understand what is happening. I can see some issues
with the way ranges are implemented in the current sources (but not 3.2.x, I
think). I will start a discussion on the Octave maintainers mailing list
about that.
I also see what I think is unusual behavior of fmod on my system. What does
the following program print on your system where you have the problem with
rem/mod? Here, I see
x = 0.5
y = 0.1
floor (x / y) = 5
x - y * floor (x / y) = 0
fmod (x, y) = 0.1
which is definitely a surprising result. Since fmod is the function used by
Octave to compute the remainder, this is the same result that Octave will
compute on my system. If this is a bug, then I think the right place to fix
it is in the system math library, or perhaps in gnulib.
#include <iostream>
#include <cmath>
int
main (void)
{
double x = 0.5;
double y = 0.1;
std::cout << "x = " << x << std::endl;
std::cout << "y = " << y << std::endl;
std::cout << "floor (x / y) = " << floor (x / y) << std::endl;
std::cout << "x - y * floor (x / y) = " << x - y * floor (x / y) <<
std::endl;
std::cout << "fmod (x, y) = " << fmod (x, y) << std::endl;
return 0;
}
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- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, anonymous, 2010/11/01
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, Rik, 2010/11/02
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/05
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, John W. Eaton, 2010/11/05
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/05
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, Rik, 2010/11/05
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/06
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/06
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3,
John W. Eaton <=
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, John W. Eaton, 2010/11/06
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/07
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, John W. Eaton, 2010/11/07
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, Rik, 2010/11/07
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, John W. Eaton, 2010/11/09
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/13
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, Rik, 2010/11/18
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/19
- [Octave-bug-tracker] [bug #31512] Problem with code on Linux octave 3.2.3 and 3.2.4/// OK on mac w/ 3.2.3, kody law, 2010/11/19