I am trying to us torch.mm to do the following matrix operation,
If  matrix is a M * N tensor,  batch  is a N * B tensor, how can i achieve,
In each batch, matrix @ batch_i, which gives M, and put the batch size together, the output tensor looks like M * B
There two questions here,
1.To use torch.bmm, it seems need both matrix need be batch, but my first input is not
2. The batch size need be the first dimension, while my batch size in the end