Your metric is only applicable within the context of the problem domain. In 3-d graphics, the inverse square root (1 divided by the square root of x) is an extr

Your metric is only applicable within the context of the problem domain. In 3-d graphics, the inverse square root (1 divided by the square root of x) is an extremely common operation (such as for normalizing vectors), but the inverse cube root pretty much isn't used, so it's safe to assume you will not need to extend it to arbitrary powers. As the designer of the code, you would understand that the inverse square root is a standalone problem.