[mailto:r-help-boun...@r-project.org] On
Behalf Of Ravi Varadhan
Sent: Tuesday, July 14, 2009 7:35 PM
To: 'UyenThao Nguyen'; 'spencerg'
Cc: r-help@r-project.org
Subject: Re: [R] nls, reach limit bounds
I took a quick look at drcpackage and the drm function. The drm()
function uses optim (BFGS method
, July 14, 2009 4:35 PM
To: 'UyenThao Nguyen'; 'spencerg'
Cc: r-help@r-project.org
Subject: Re: [R] nls, reach limit bounds
I took a quick look at drcpackage and the drm function. The drm()
function uses optim (BFGS method). So, that is one diffference. However,
without looking at your code on how
relationship between their parameters although
the fits were similar.
Thank you.
Uyen
-Original Message-
From: Ravi Varadhan [mailto:rvarad...@jhmi.edu]
Sent: Monday, July 13, 2009 3:32 PM
To: 'spencerg'; UyenThao Nguyen
Cc: r-help@r-project.org
Subject: RE: [R] nls, reach limit bounds
Hi
-Original Message-
From: UyenThao Nguyen [mailto:ungu...@tethysbio.com]
Sent: Tuesday, July 14, 2009 7:07 PM
To: Ravi Varadhan; 'spencerg'
Cc: r-help@r-project.org
Subject: RE: [R] nls, reach limit bounds
Hi Ravi and Spencer,
Thank you
, 2009 9:50 PM
To: UyenThao Nguyen
Cc: r-help@r-project.org
Subject: Re: [R] nls, reach limit bounds
Have you plotted the data? There are two standard sources of
non-convergence problems like this: First, there may not be enough
information in your data to estimate all four parameters
Have you plotted the data? There are two standard sources of
non-convergence problems like this: First, there may not be enough
information in your data to estimate all four parameters. Second, if
that's not the case, then your starting values are not appropriate.
I routinely
Hi,
I am trying to fit a 4p logistic to this data, using nls function. The function
didn't freely converge; however, it converged if I put a lower and an upper
bound (in algorithm port). Also, the b1.A parameter always takes value of the
upper bound, which is very strange. Has anyone
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