[Octave-bug-tracker] [bug #53299] Several rand/randn bugs with state/seed behavior.

[Mike Miller]

Follow-up Comment #5, bug #53299 (project octave):

Since I spent a lot of time looking at rand* recently with respect to the test
suite, I agree with Rik's assessment that, while confusing, the functions do
seem to be behaving as I expect.

There are the "old" vs "new" algorithms, which switch silently under the hood
when a user sets "state" or "seed", but not when simply asking for the current
value of "state" or "seed". And there is no way to query which algorithm is
currently in use.

The only new bit that Rik states that I didn't know is under the old
algorithms, the rande/randg/randp functions depend on the others.

In summary, never use "seed".

Aside: I would really like to know why this test passes only when setting
"seed" to get a random array from the old algorithm:

https://hg.savannah.gnu.org/hgweb/octave/file/2d68dc548561/libinterp/corefcn/conv2.cc#l274

> It would be nicer to simply remove the old random number generator
functionality entirely.

Absolutely, as well as move the state out of global program state and into a
class so that multiple independent random number generators can be
instantiated.

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