[GRASS-dev] using rand(x,y) in r.mapcalc (grass7)

Glynn Clements glynn at gclements.plus.com
Tue Jul 22 16:59:10 PDT 2014

Vaclav Petras wrote:

> Anyway, the reproducibility would be really nice considering GRASS
> scientific audience, however are you sure that different systems will give
> same random number for the same seed?

They will from now on, because I've replaced the use of the system's
PRNG (either rand or mrand48/drand48) with a portable implementation
of the latter.

> > What about time + process id?

That's what's done now (if -s is used). Although we could probably do
with a better hash (currently, it's just addition) and/or more entropy

Glynn Clements <glynn at gclements.plus.com>

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