Step length change
Step length change

The differentiation steps were too long in some cases, in particular
causing problems for Simplex. The shorter steps here will give higher
radii, but I think the price is worth paying.

arosale4/q2mm,ericchansen/q2mm,ericchansen/q2mm,Q2MM/q2mm,arosale4/q2mm,Q2MM/q2mm