PyTorch: purpose of addmm function

问题:

What is the purpose of the following PyTorch function (doc):

torch.addmm(beta=1, mat, alpha=1, mat1, mat2, out=None)

More specifically, is there any reason to prefer this function instead of just using

beta * mat + alpha * (mat1 @ mat2)

回答1:

The addmm function is an optimized version of the equation beta*mat + alpha*(mat1 @ mat2). I ran some tests and timed their execution.

• If beta=1, alpha=1, then the execution of both the statements (addmm and manual) is approximately the same (addmm is just a little faster), regardless of the matrices size.

• If beta and alpha are not 1, then addmm is two times faster than the manual execution for smaller matrices (with total elements in order of 10⁵). But, if matrices are large (in order of 10⁶), the speedup seems negligible (39ms v/s 41ms)