How to set the weight of each wav in the mix_2_spk_tr.txt, mix_2_spk_cv.txt...

[soliloquy1983]

I am a newbie. Since I have no wsj0 datasets, I have to create mixtures on my own datasets.
In the mix_2_spk_tr/cv/tt.txt, each wav is assigned with a weight, just like:
wsj0/si_tr_s/01t/01to030v.wav 0.76421 wsj0/si_tr_s/20g/20ga010m.wav -0.76421
wsj0/si_tr_s/40e/40ec020o.wav 1.3218 wsj0/si_tr_s/20c/20ca010n.wav -1.3218
....
I have two questions about these files:

1. Are these files randomly selected?
2. Are these weight randomly set?
   Thanks!

[aishoot]

@soliloquy1983 Yeah, randomly.