Presumably you prescale the minimum to 1. In that case your minimum will now be a little larger than 1 (the $-a$'s in my expression took care of that). But it is small, and if it works for you, great.

Feb 3, 2021 · First, some background. Let's review the underlying math and notation. Transformation $\mathbf {T}$ has four free parameters: scale $\lambda$, rotation $\theta$, …