Performance measures

Introduction
Here is a selection of measures you can use for assessing the performance of your model.

Nash-Sutcliffe efficiency
This one is implemented as NSeff in the topmodel package, and takes two vectors, containing the simulated (Qsim) and observed (Qobs) discharge:

NSeff <- function (Qobs, Qsim){ Qsim <- Qsim[!is.na(Qobs)] Qobs <- Qobs[!is.na(Qobs)] Qobs <- Qobs[!is.na(Qsim)] Qsim <- Qsim[!is.na(Qsim)] NS <- 1 - (sum((Qobs - Qsim)^2)/sum((Qobs - mean(Qobs))^2)) return(NS) }  Eff <- NSeff(Qobs,Qsim)