Random must not ignore seed in multiple instances

[breznak]

Random should not use static members, esp static_gen and static_is_seeded, otherwise the first instance of random sets the seed, but seed is ignored for any other random instance during the runtime!

From Random.cpp

bool static_gen_seeded = false;  //TODO avoid the static variables?
std::mt19937 static_gen;

Example of the problem:

sp = SpatialPooler(..., seed = 42); //OK, has rng with seed 42
rng = Random(1); //has rng with seed 42, not 1!

and

rng = Random(1); //OK, seed = 1
sp = SpatialPooler(..., seed = 42); //has rng with seed 1!

[ctrl-z-9000-times]

Random only uses the static generator if seed == 0. If seed > 0 then it uses the given seed.

This is from the unit tests for Random. I think it would reproduce this bug, if it existed:

  Random r1(1);
  Random r2(2);
  ASSERT_NE(r1.getUInt32(), r2.getUInt32());

[breznak]

This is from the unit tests for Random. I think it would reproduce this bug, if it existed:

yes, I was also looking into this and my description is imprecise.

Still, in WIP PR #397 I had different results for these scenarios (compared with deterministic/"gold" check for SP/TM):

Random r(1);
SP sp();

vs. 

SP sp;
Random r;

I'll verify if this is the case, or some other mistake on my side.

[breznak]

Closing as won't fix, this was my mistake.
Sorry for confusion.

The above scenario passes OK in both cases. The "bug" was that I had mismatch between hand-written values for SP, encoder outputs using different rng seed.