On Saturday, 26 November 2016 at 20:13:36 UTC, Andrei
Alexandrescu wrote:
On 11/26/16 11:31 AM, Ilya Yaroshenko wrote:
Hey,
32-bit Mt19937 random number Generator is default in Phobos.
It is default in Mir too, except that 64-bit targets use
64-bit Mt19937 instead.
Congrats! Also thanks for using the Boost license which would
allow backporting the improvements to Phobos. Who'd be up for
it?
PR is now on Phobos, and in the process of looking at this
together, Ilya and I resolved a number of issues both in this
code and in mir.random:
https://github.com/dlang/phobos/pull/5011
There is unfortunately one serious blocker to this PR. In order
to allow it to be a drop-in replacement for the previous Phobos
implementation, I had to find a means to default-initialize its
internal state at compile time so that it would match what would
be there if it was explicitly seeded with the default seed.
The method I developed works fine with LDC, but fails with DMD:
the internal state of the generator winds up as all zeros, except
for the `State.z` parameter which mysteriously ends up at the
correct value. This would suggest that somehow the generated
state is being overwritten _after_ being correctly generated,
rather than not correctly generated in the first place.
Any chance that someone with more CTFE-fu than myself could take
a glance and advise what might be wrong (or how to work around
it)?
