Displaying 2 results from an estimated 2 matches for "nlsobject".
2010 Sep 05
0
cov.unscaled in NLS - how to define cov.scaled to make comparable to SAS proc NLIN output - and theoretically WHY are they different
...the cov.unscaled from R's NLS to a correlation and compare it to
SAS's correlation. They are identical;
e.g., cov2cor(summary.nls.L$cov.unscaled)
I have even written a function to convert an NLS object into a "cov.scaled"
element that is equivalent to SAS:
scaledCOV = function (nlsObject)
{
myFactor = nlsObject$cov.unscaled[1,1]/(nlsObject$coefficients[1,2]^2);
myScaled = nlsObject$cov.unscaled/myFactor;
myScaled;
}
so with this function I can determine the factor difference between R and
SAS (which is different with each data run of NLS and NLIN). This factor is
based on the...
2005 Jan 10
1
How to obtain nls parameter estimates
How can I receive parameter estimates for a given curve that has been fit with the NLS function.
The problem is that I have a "n parameter" curve and I want the optimal fit. The NLS procedure gives me final function values and not the individual parameter estimates that were used to define this "best" fit. What function can I use to get these parameters?
Thanks