So if I just run it then the training will not be accurate right?

Well the gradients won’t be correct.

If so, is there anyway that I can attach the gradient of the original tensor to the new tensor converted from numpy array?

No. For the gradients to be properly computed you need to only use pytorch’s functions.
Note that you can add new elementary function where you define both the forward and backward if you don’t know how to write the forward using pytorch’s functions (see tutorial here 10). But that will be more complex as you need to implement the backward yourself.