Hamish wrote: > Sören Gebbert wrote: > > But the gmath lu solver is code from the numerical recipes, > > we have to rewrite this method. > > re N.R. code in GRASS, > http://thread.gmane.org/gmane.comp.gis.grass.devel/18764/focus=18791 > > (this is just fyi, it is of course a good idea to remove the issue > altogether by removing any code based on N.R.) > > > On 2007-02-26, Stefano wrote: > > Note that previous GRASS development team (CERL) had > > an agreement with the authors of NR, to use freely NR: > > [grass5/src.nonGPL/README] > /* Based on "Numerical Recipies in C; The Art of Scientific Computing" > (Cambridge University Press, 1988). Copyright (C) 1986, 1988 by > Numerical Recipes Software. Permission is granted for unlimited > use within GRASS only. > [...] > Bill Press > */ > [sic] > > If this agreement was with CERL I assume that means it predates GRASS > moving to the GPL. The GPL audit alluded to in grass5/TODO.txt and > grass5/src.nonGPL/ should have caught all known occurrences. > > > grass-5.4.0$ grep -rI "Numerical Recipes" * | cut -f1 -d: | uniq > TODO.txt > html/grass_commandlist.html > html/html/r.kineros.html > html/html/r.surf.random.html > html/html/r.tribs.html > src/raster/r.surf.gauss/main.c > src/raster/r.surf.gauss/README > src/raster/r.surf.gauss/source.txt > src/raster/r.surf.random/README > src/raster/r.surf.random/SOURCE.TXT > src.contrib/CERL/sites/s.surf.krig/NR.c > src.contrib/CERL/sites/s.surf.krig/nrutil.c > src.nonGPL/display/d.param.scale/CHANGES > src.nonGPL/README > > > A quick grep for "Numerical Recipes" in 6.3-cvs finds these references: > raster/r.surf.random > raster/r.surf.gauss > > Although both modules' main.c ask: /* still true ?*/
Personally, I think that NRS would have a hard time claiming copyright over what is essentially a direct translation of the Box-Mueller algorithm to C. If you want to be able to cite a GPL source for the code, take the version from GSL: http://sources.redhat.com/cgi-bin/cvsweb.cgi/gsl/randist/gauss.c?rev=1.24&content-type=text/x-cvsweb-markup&cvsroot=gsl double gsl_ran_gaussian (const gsl_rng * r, const double sigma) { double x, y, r2; do { /* choose x,y in uniform square (-1,-1) to (+1,+1) */ x = -1 + 2 * gsl_rng_uniform_pos (r); y = -1 + 2 * gsl_rng_uniform_pos (r); /* see if it is in the unit circle */ r2 = x * x + y * y; } while (r2 > 1.0 || r2 == 0); /* Box-Muller transform */ return sigma * y * sqrt (-2.0 * log (r2) / r2); } Note: gsl_rng_uniform_pos() just returns a random double in the range 0-1, so you can use "(double) rand() / RAND_MAX" for that. -- Glynn Clements <[EMAIL PROTECTED]> _______________________________________________ grass-dev mailing list [email protected] http://grass.itc.it/mailman/listinfo/grass-dev
