changed behavior of rand_seed in BRSA

[lcnature]

Per request by @mshvartsman, rand_seed argument now defaults to None, and BRSA won't reset random seed if None is provided.
The suppression of warning is also removed.

[mihaic]

We now have guidelines on using random numbers:
https://github.com/IntelPNI/brainiak/blob/master/CONTRIBUTING.rst#standards

Therefore, all new commits should conform to the standard. Specifically, you should not use numpy.random.random(); you should use numpy.random.RandomState.

[lcnature]

Hi @mihaic Sorry I am a bit confused. How should numpy.random.RandomState replace numpy.random.random()? I thought the former sets the state while the latter just return a random number.
Thanks!

[lcnature]

Does that mean I should call this random_state = check_random_state(random_state), and from then on, replace all np.random with random_state?

[mihaic]

RandomState objects also have several methods for generating random numbers. RandomState.random_sample() is a good replacement for numpy.random.random():
https://docs.scipy.org/doc/numpy/reference/generated/numpy.random.RandomState.random_sample.html

You do not need to use check_random_state.

[lcnature]

Please see if the new commit is correct. Thanks!

[mihaic]

Please document this attribute in the class docstring. Could be something like this:

random_state_: `RandomState`
    Random number generator initialized using random_state

[lcnature]

Thanks. Just added exactly this text.