zsumlp(o, x=0, y=0, p=2)
zsumlpgra(o, x=0, y=0, p=2, partial=F)loca.p class.partial=T means
ignore such point to compute the gradient. This option is mainly for internal use.zsumlp returns the objective function of the min-sum location
problem with $l_p$ norm, $\sum_{a_i \in o} w_i d(a_i, (x,y))$, where $d(a_i, (x,y))$ gives the
distances between $a_i$ and the point $(x,y)$ using $l_p$ norm. zsumlpgra returns the gradient vector of the function zsumlp.
zsum, orloca.es-package y zsumlpmin.