On 2008-10-19 20:55+0200 Pieter-Jan Busschaert wrote:
> Hello,
>
>
> I have recently been testing libcsironn (the version from plplot).
> I have come across 2 errors :
>
> 1) in trunk/lib/nn/delaunay.c : delaunay_circles_find()
>
> line 679 : if (tid < 0 || tid == nn) {
>
> should be changed to
>
> line 679 : if (tid < 0 || i == nn) {
>
>
> This bug leads to "random" results, ie: the result of the interpolation
> depended on the search just before.
>
>
> 2) in trunk/lib/nn/nncommon.c : circle_contains()
>
> line 90 : return hypot(c->x - p->x, c->y - p->y) <= c->r;
>
> should be changed to
>
> line 90 : return hypot(c->x - p->x, c->y - p->y) < c->r + 0.000001;
>
>
> This is just a standard floating point equality checking bug. It surfaces
> when asking to interpolate on one of the given x,y coordinates. It gives the
> result of delaunay_xytoi returning a certain triangle for the point, but
> then the circle_contains() function says this point is no part of the
> circumcircle.
>
>
> I don't know if there is any "upstream" version of this library left that
> maintains this code ?
>
Hi Pieter-Jan:
Welcome to the plplot-devel mailing list!
The current status is Rafael is trying to get back in contact with the
author of this extremely useful library to get it relicensed as LGPL rather
than the current CSIRO license which has some issues which make it
impossible for Debian to distribute it in binary form any more. Once we
reestablish contact, we should also see whether the author has a later
version of the code than when we contacted him many years ago.
Regardless of those issues, thanks for your above suggested changes. Will
someone here who is familiar with our current version of the libcsironn code
please evaluate those proposed changes and make the commit if they agree with
them?
Alan
__________________________
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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