  Nonparametric estimators of a regression function with circular response and
Rd-valued predictor are considered in this work. Local polynomial type
estimators are proposed and studied. Expressions for their asymptotic biases
and variances are derived, and some guidelines to select asymptotically local
optimal bandwidth matrices are also given. The finite sample behavior of the
proposed estimators is assessed through simulations and their performance is
also illustrated with a real data set.
