Displaying 2 results from an estimated 2 matches for "genuchten".
2005 Sep 26
2
nls and na/Nan/Inf error
...have written the function as shown
below according to the logist example in Ch8 of Pinheiro & Bates. I am
getting the following error (R version 2.1.1)
*Error in qr(attr(rhs, "gradient")) : NA/NaN/Inf in foreign function
call (arg 1)*
Below is the function and data.
/# the van genuchten moisture release function
vanGen <- function(x, Vr, Vm, alpha, lamda) {
if (Vr < 0) Vr <- 0
Vr + (Vm - Vr)/((1+(alpha*x)^lamda)^(1-1/lamda))
}
vanGen <- deriv(~Vr + (Vm - Vr)/((1+(alpha*x)^lamda)^(1-1/lamda)),
c("Vr", "Vm", "alpha", "lamda"...
2011 Mar 15
1
Problem with nls.lm function of minpack.lm package.
Dear R useRs,
I have a problem with nls.lm function of minpackl.lm package.
I need to fit the Van Genuchten Model to a set of data of Theta and hydraulic conductivity with nls.lm function of minpack.lm package.
For the first fit, the parameter estimates keep changing even after 1000 iterations (Th)
and
I have a following error message for fit of hydraulic conductivity (k);
Reason for termination: The...