Compute weight value
update_wt(y, ypre, weights, cfun, s, dfun, delta=0.0001)
input value of response variable
predicted value of response variable
optional numeric vector of weights.
integer from 1-8, concave function as in ccglm_fit
integer value, convex function as in ccglm_fit
a numeric value, see details in ccglm_fit
a positive small value, see details in ccglm_fit
Weight value
Zhu Wang (2020) Unified Robust Estimation via the COCO, arXiv e-prints, https://arxiv.org/abs/2010.02848