It would appear that the input might not have the right shape (should it be 1x3708000 or even 1x1x3708000 or something like this? If so, you need to use torch::Tensor::permute or somesuch).
For me, making a habit of checking the input shapes and possible a small portion of the tensor (say slicing the first 5 elements in each dimension) has reduced a great deal of confusion with the outputs when moving between Python and C++.
Best regards
Thomas