Dear Rolf,
One thing that sometimes makes nls easier to apply is using the 'formula'
argument like you would use the 'fn' argument of optim. That is, if you
have a residual function that has arguments x, y, a, b and you need to
optimize a and b, you would make a call like
nls(~resid(x,y,a=astart
I have never had much success in using nls(). If you scan the archives
you will find one or two postings from me on this topic. I have
received
no useful responses to these postings.
I have found that anything that I tried (and failed) to do using nls()
could be done quite easily using optim(
Gavin Simpson wrote:
> hits=-2.6 tests=BAYES_00
> X-USF-Spam-Flag: NO
>
> On Wed, 2008-01-16 at 11:02 +0100, Janice Kielbassa wrote:
>> Hello!
>>
>> I want to do a non-linear regression with 2 explanatory variables
>> (something like : length ~ a * time * exp( b* temperature)), having a
>> data
hits=-2.6 tests=BAYES_00
X-USF-Spam-Flag: NO
On Wed, 2008-01-16 at 11:02 +0100, Janice Kielbassa wrote:
> Hello!
>
> I want to do a non-linear regression with 2 explanatory variables
> (something like : length ~ a * time * exp( b* temperature)), having a
> data set (length, time, temperature).
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