It is hard to understand what is it that you’re having problem with, as it is easy to combine two tensors, e.g.: 1) sum them 2)torch.cat 3)trainable combination, simplest looks like input1.matmul(weight1) + input2.matmul(weight2)
Maybe you mean multi-stage training, in this case you can use Tensor.detach() on output from pre-trained part of the network to “freeze” it. You can then combine normal and detached tensors anyway you need to.