On 8/8/07, Michael Petram <[EMAIL PROTECTED]> wrote:
> Dear all
>
> I have got some problems with a least-squares regression using the function
> nls.
>
> I want to estimate h, k and X of the following formula by using nls :
>
> exp(2*200*(q^2-4*h/k-0.25+(2/k-0.5+4*h^2/k^2)*log(abs((k*q^2+2*h*q-1)
Dear all
I have got some problems with a least-squares regression using the function nls.
I want to estimate h, k and X of the following formula by using nls :
exp(2*200*(q^2-4*h/k-0.25+(2/k-0.5+4*h^2/k^2)*log(abs((k*q^2+2*h*q-1)/(0.25*k-h-1)/((-k*q^2-2*h*q+1)*X)
y as defined by c(0.009747
The start list should only contain parameters, not x. Also
your function appears to have multiple errors including
reference to temp (presumably intended as tmp?)
and b(x-m) which presumably should be b*(x-m).
On 7/14/05, Yimeng Lu <[EMAIL PROTECTED]> wrote:
> Sorry that I specified the x as
> x=
Sorry that I specified the x as
x=c(0, 0.4, 0.7, 1, 1.4, 1.6, 1.8, 2:10)
The error message is the same.
Thanks.
Hanna
- Original Message -
From: Yimeng Lu
To: r-help@stat.math.ethz.ch
Sent: Thursday, July 14, 2005 11:19 PM
Subject: problems with nls function
Hello,
Hello,
I was trying to fit a generalized logistic curve and my code for testing
if the function "nls" is working is like this
###
#define the generalized logistic curve function
glogit=function(a, b, c, m, t, x)
{
tmp = 1/(1 + t * exp(-b * (x - m)))^(1/t)
model.func = a + tmp * c
#define t