In first minibatch, the output of multilabelmarginloss()  Loss: 246.707458
the second, it is zero.
In[10]: output_var.data
Out[10]:
2.3264e+03  6.5879e+01 -9.7149e+00  …  -2.6423e+01  2.1553e+00  2.3724e+01
2.9392e+03  8.3356e+01 -1.2624e+01  …  -3.3264e+01  2.6289e+00  2.9792e+01
2.1745e+03  6.1491e+01 -9.2812e+00  …  -2.4580e+01  1.9765e+00  2.2134e+01
2.4772e+03  7.0001e+01 -1.0521e+01  …  -2.8103e+01  2.1341e+00  2.5243e+01
2.0916e+03  5.9231e+01 -8.8647e+00  …  -2.3580e+01  1.9928e+00  2.1346e+01
[torch.cuda.FloatTensor of size 5x252 (GPU 0)]
In[11]: target_var.data
Out[11]:
0     0     0  ...      0     0     0
0     0     0  ...      0     0     0
0     0     0  ...      0     0     0
0     0     0  ...      0     0     0
0     0     0  ...      0     0     0

[torch.cuda.LongTensor of size 5x252 (GPU 0)]