Re: [R] error using nls with logistic derivative

2012-04-17 Thread Francisco Mora Ardila
It seems to work! Thanks and sorry for the personal message Francisco On Tue, 17 Apr 2012 09:09:24 +0200, peter dalgaard wrote > On Apr 17, 2012, at 06:23 , Francisco Mora Ardila wrote: > > > Hi > > > > I´m trying to fit a nonlinear model to a derivative of the logistic function > > > > y = a

Re: [R] error using nls with logistic derivative

2012-04-17 Thread John C Nash
2 1.080 residual sum-of-squares: 50.5 Number of iterations to convergence: 0 Achieved convergence tolerance: 4.818e-07 > On 04/17/2012 06:00 AM, r-help-requ...@r-project.org wrote: > Message: 112 > Date: Mon, 16 Apr 2012 23:23:07 -0500 > From: "Francisco Mora Ardila" >

Re: [R] error using nls with logistic derivative

2012-04-17 Thread Gabor Grothendieck
On Tue, Apr 17, 2012 at 12:23 AM, Francisco Mora Ardila wrote: > Hi > > I´m trying to fit a nonlinear model to a derivative of the logistic function > > y = a/(1+exp((b-x)/c)) (this is the parametrization for the SSlogis function > with nls) > > The derivative calculated with D function is: > >>

Re: [R] error using nls with logistic derivative

2012-04-17 Thread peter dalgaard
On Apr 17, 2012, at 06:23 , Francisco Mora Ardila wrote: > Hi > > I´m trying to fit a nonlinear model to a derivative of the logistic function > > y = a/(1+exp((b-x)/c)) (this is the parametrization for the SSlogis function > with nls) > > The derivative calculated with D function is: > >> l

[R] error using nls with logistic derivative

2012-04-16 Thread Francisco Mora Ardila
Hi I´m trying to fit a nonlinear model to a derivative of the logistic function y = a/(1+exp((b-x)/c)) (this is the parametrization for the SSlogis function with nls) The derivative calculated with D function is: > logis<- expression(a/(1+exp((b-x)/c))) > D(logis, "x") a * (exp((b - x)/c) * (1