Created by: daming-lu

When we stabilize all the randomness and run the same training twice on GPU (same GPU core), the results are different by a tiny precision. This is NOT happening on CPU.

See the attachments. The demo code is in this PR

vimdiff w2v_nocuda_t1.txt w2v_nocuda_t2.txt  // no difference

vimdiff w2v_t1_cuda.txt w2v_t2_cuda.txt  // has some tiny difference

w2v_nocuda_t1.txt w2v_nocuda_t2.txt w2v_t1_cuda.txt w2v_t2_cuda.txt