Re: [R] singular gradient error in nls

2011-10-11 Thread Bert Gunter
Katie: I would say that this is not an R question, so I would suggest that either a) You ask it on a statistics help website like stats.stackexchange.com or b) You consult with someone locally who knows about nonlinear regression (possibly a statistician, but not necessarily so). -- Bert On T

[R] singular gradient error in nls

2011-10-11 Thread Katie Tully
I am trying to fit a nonlinear regression to infiltration data in order to determine saturated hydraulic conductivity and matric pressure. The original equation can be found in Bagarello et al. 2004 SSSAJ (green-ampt equation for falling head including gravity). I am also VERY new to R and to non