So, Michael Stahl commented in the bug that we do have our own
random number generator function. One way is to just replace the
direct call to rand() to this function instead. That should be very
easy to do and I have no objection against it.
Just to be clear, I believe glibc's implementation of rand() is
excellent and doesn't need replacement unless one needs particular
statistical properties (the problem is only with windows rand()).
Boost offers generators I believe similar to glibc's rand() as well as
a few which have even better statistical properties but are slower.
The advantage of boost is that it includes transformations which lead
to all sorts of distributions ([0-1] uniform, normal, exponential ...).
This would allow for easy implementation of new functions like
RANDNORMAL(mu, sigma)
As for the bug report, if he's referring to
./core/sal/inc/rtl/random.h
then I can't see any function we can easily use for our purposes. It
seems to me all this does is generating and managing a random binary
array. From a quick look at the source it seems to use the
Wichmann-Hill algorithm, which apparently has a period of 16 million
(2^24) which is worse than glibc's rand().
Cheers, Tino
./core/sal/rtl/source/random.cxx
#define RTL_RANDOM_RNG(x, y, z) \
{ \
(x) = 170 * ((x) % 178) - 63 * ((x) / 178); \
if ((x) < 0) (x) += 30328L; \
\
(y) = 171 * ((y) % 177) - 2 * ((y) / 177); \
if ((y) < 0) (y) += 30269L; \
\
(z) = 172 * ((z) % 176) - 35 * ((z) / 176); \
if ((z) < 0) (z) += 30307L; \
}
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