From wdunlap at tibco.com  Wed Mar  4 16:31:21 2015
From: wdunlap at tibco.com (William Dunlap)
Date: Wed, 4 Mar 2015 07:31:21 -0800
Subject: [Rd] nonlinear least square
In-Reply-To: <CAObCh3WhDRz1inw_63SOu9hxCO0-xOnsF7XR8sq4MqfMgy4yTg@mail.gmail.com>
References: <CAObCh3WhDRz1inw_63SOu9hxCO0-xOnsF7XR8sq4MqfMgy4yTg@mail.gmail.com>
Message-ID: <CAF8bMcachwf+6r3WM2djv8oPdG7gcnW7c9=71P-LZVx0PWeozQ@mail.gmail.com>

Look at the 'self-starting' functions for nls(), such as SSasymp().

Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Mar 4, 2015 at 5:01 AM, Evans Otieno Ochiaga <
evansochiaga at aims.ac.za> wrote:

> Hi to all,
>
> Is there a way we can fit a non linear model to a data using non linear
> least square method without necessarily initialising the parameters of the
> model. I find it hard to get the initial value of the parameter. Below is a
> sample of the code I have.
>
>
>
>
>
>
> *nachman<-nls(OARmedium$OCCUPANCY~1exp(-alpha*OARmedium$MEAN^beta),start=list(alpha=0.2,beta=0.1),data=OARmedium)summary(nachman)*
> Thanks,
>
>
> *Evans Ochiaga*
>
> *African Institute for Mathematical Sciences*
>
> *6 Melrose Road*
>
> *Muizenberg, South Africa*
>
> *Msc in Mathematical Sciences+27 84 61 69 183 *
>
> *"When I cannot understand my Father?s leading, And it seems to be but hard
> and cruel fate, Still I hear that gentle whisper ever pleading, God is
> working, God is faithful?Only wait."*
>
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>
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[Rd] nonlinear least square
William Dunlap