Objective functions

nse	Nash-Sutcliffe Efficiency (NSE) as per Nash and Sutcliffe, 1970.
kge	Original Kling-Gupta Efficiency (KGE) and its three components (r, α, β) as per Gupta et al., 2009.
kgeprime	Modified Kling-Gupta Efficiency (KGE') and its three components (r, γ, β) as per Kling et al., 2012.
kgenp	Non-Parametric Kling-Gupta Efficiency (KGENP) and its three components (rS, αNP, β) as per Pool et al., 2018.
rmse	Root Mean Square Error (RMSE).
mare	Mean Absolute Relative Error (MARE).
pbias	Percent Bias (PBias).

Bounded versions

nse_c2m	Nash-Sutcliffe Efficiency (NSE) in a bounded version as per Mathevet et al., 2006.
kge_c2m	Original Kling-Gupta Efficiency (KGE) in a bounded version as per Mathevet et al., 2006.
kgeprime_c2m	Modified Kling-Gupta Efficiency (KGE') in a bounded version as per Mathevet et al., 2006.
kgenp_c2m	Non-Parametric Kling-Gupta Efficiency (KGENP) in a bounded version as per Mathevet et al., 2006.