Displaying 20 results from an estimated 700 matches similar to: "How should a SelfStart function handle illegal parameter values?"
2009 Sep 21
1
How to use nls when [selfStart] function returns NA or Inf??
Hi Everyone,
I posted this a couple of weeks ago with no responses. My interface (via
gmane) seemed a bit flakey at the time, so I'm venturing to repost with some
additional information.
I'm trying to write selfStart non-linear models for use with nls. In these
models some combinations of parameter values are illegal; the function value
is undefined.
That's OK when calling the
2017 Jul 30
0
Kalman filter for a time series
> structSSM
Is no longer part of KFAS. All you needed to do was:
library(KFAS)
?KFAS
and you would have seen that if you went to the index. A structural state space model is now built up from its components, much like in LM. Look at;
?SSModel
-Roy
> On Jul 29, 2017, at 9:26 PM, Staff <rbertematti at gmail.com> wrote:
>
> I found an example at
>
2009 Oct 14
0
Problem with NLSstClosestX; and suggested fix
Problem is demonstrated with this code, intended to find the approximate 'x'
at which the 'y' is midway between the left and right asymptotes. This
particular data set returns NA, which is a bit silly!
--------------
sXY <- structure(list(x = c(0, 24, 27, 48, 51, 72, 75, 96, 99), y =
c(4.98227,
6.38021, 6.90309, 7.77815, 7.64345, 7.23045, 7.27875, 7.11394,
6.95424)), .Names =
2017 Jul 30
4
Kalman filter for a time series
I found an example at
http://www.bearcave.com/finance/random_r_hacks/kalman_smooth.html shown
below. But it seems the structSSM function has been removed from KFAS
library so it won't run. Does anyone know how to fix the code so that it
runs?
library(KFAS)
library(tseries)
library(timeSeries)
library(zoo)
library(quantmod)
getDailyPrices = function( tickerSym, startDate, endDate )
{
2002 Jul 19
1
selfStart function problem
Hello, list,
I am making a self-starting nonlinear function to model the relation of tree height (H)
and diameter (D) in a forest stand. The function I am trying is
H=a*exp[b*(D+5.8)^(-c)].
To calculate the initial estimates of the parameters, I linearized the formula by taking
logarithms and fixing the parameter c=1. Then I calculated the initial estimates of a
and b using lm() on the
2009 Oct 17
1
custom selfStart model works with getInitial but not nls
Hello,
I'm having problems creating and using a selfStart model with nlme. Briefly,
I've defined the model, a selfStart object, and then combined them to make a
selfStart.default model.
If I apply getInitial to the selfStart model, I get results. However, if I try
usint it with nls or nlsList, these routines complain about a lack of initial
conditions.
If someone could point out
2010 Jan 01
4
How to use read.table with Hebrew column names ?
Hello dear R help group,
I am trying to read a .txt file, with Hebrew column names, while keeping the
column names looking well in R - but without success.
I uploaded an example file to:
http://www.talgalili.com/files/aa.txt
And am trying the command:
read.table("http://www.talgalili.com/files/aa.txt", header = T, sep = "\t")
This returns me with:
X.....ª X...ª......
2009 Nov 12
0
writing selfStart models that can deal with treatment effects
Hello,
I'm trying to do some non-linear regression with 2 cell types and 4 tissue
type treatments using selfStart models
Following Ritz and Streibig (2009), I wrote the following routines:
##Selfstart
expDecayAndConstantInflowModel <- function(Tb0, time, aL, aN, T0){
exp(-time*aL)*(T0*aL+(-1+exp(time * aL))*Tb0 * aN)/aL
}
expDecayAndConstantInflowModelInit <- function(mCall, LHS,
2006 Nov 13
2
notepad selfstart on login
hi all;
I'm starting in PDC and need some help, i'm using samba for pdc but without
ldap, and all time that a user make login, open a notepad with the content:
[.ShellClassInfo]
LocalizedResourceName=@%SystemRoot%\system32\shell32.dll,-21787
or
[DeleteOnCopy]
Owner=cesar
Personalized=5
PersonalizedName=My documents
and all folder have a document Desktop.ini...
someone can say me why
2008 Aug 18
1
"nested" getInitial calls; variable scoping problems
Hi All,
Another nls related problem (for background, I'm migrating a complicated
modelling package from S-plus to R).
Below I've reduced this to the minimum necessary to demonstrate my problem
(I think); the real situation is more complicated.
Two similar selfStart functions, ssA and ssB.
The 'initial' function for ssB modifies its arguments a little and then
calls getInital
2009 Aug 26
2
faulty formatting of toLatex(sessionInfo())
Dear all
I am writing an Sweave document and have encountered formatting issues
with the "locale" part of toLatex(sessionInfo()). The fact that there
is no spaces between the various "locale" variables means that LaTeX
cannot easily find an appropriate place to break the lines, and some
will get printed off screen.
Below is the text output, and this .pdf document [1] shows the
2006 Feb 12
1
lme, nlsList, nlsList.selfStart
Dear listers,
I am trying to fit a model using nlsList() using alternately a SSfol()
selfstart function or its developped equivalent formulae.
This preliminary trial works well
mydata<-groupedData(Conc~Tps|Organ,data=mydata)
mymod1<-nls(Conc~SSfol(Dose,Tps,lKe,lKa,lCl),data=mydata)
as well as a developped form:
mymod2<-nls(Conc~Dose * exp(lKe+lKa-lCl) *
2009 Aug 28
1
Plotmath, sweave and lattice graphics interaction problem
Dear List,
I have hit this problem with using a plotmath expression in an axis
label on a lattice plot I'm including in a Sweave document. The actual
document is far too long and boring (unless you are interested in the
hydrochemistry of upland lakes) to include here, but the following
minimal example reproduces the problem; basically, the PDF produced by
Sweave has missing characters in the
2009 Aug 27
5
Transform data for repeated measures
I have a dataset that I'm trying to rearrange for a repeated measures analysis:
It looks like:
patient basefev1 fev11h fev12h fev13h fev14h fev15h fev16h fev17h fev18h drug
201 2.46 2.68 2.76 2.50 2.30 2.14 2.40 2.33 2.20 a
202 3.50 3.95 3.65 2.93 2.53 3.04 3.37 3.14 2.62 a
203 1.96 2.28 2.34 2.29 2.43 2.06 2.18 2.28 2.29 a
2017 Jul 30
1
Kalman filter for a time series
> On Jul 30, 2017, at 5:10 AM, Spencer Graves <spencer.graves at effectivedefense.org> wrote:
>
>
>
> On 2017-07-29 11:26 PM, Staff wrote:
>> I found an example at
>> http://www.bearcave.com/finance/random_r_hacks/kalman_smooth.html
>
> That example is signed by "Ian Kaplan". There's a box at the bottom of the page for you to email
2017 Jul 30
0
Kalman filter for a time series
On 2017-07-29 11:26 PM, Staff wrote:
> I found an example at
> http://www.bearcave.com/finance/random_r_hacks/kalman_smooth.html
That example is signed by "Ian Kaplan". There's a box at the
bottom of the page for you to email him.
> shown
> below. But it seems the structSSM function has been removed from KFAS
> library
or it never was part of
2006 May 24
1
problem-nlme
Hi,
I have great problems with my work in R.
I look for to model the growth of fish.
I have "Longitudinal data", a serie of repeated
measures for each individual.
Using the corresponding packages "nlme" in R.
I treat to fit to the data different growth functions,
wich were entered by me.
Unfortunately for no it was arrived at the
convergence, several error messages appeared.
I
2008 Aug 29
1
nls() fails on a simple exponential fit, when lm() gets it right?
Dear R-help,
Here's a simple example of nonlinear curve fitting where nls seems to get
the answer wrong on a very simple exponential fit (my R version 2.7.2).
Look at this code below for a very basic curve fit using nls to fit to (a)
a logarithmic and (b) an exponential curve. I did the fits using
self-start functions and I compared the results with a more simple fit
using a straight lm()
2009 Jun 01
2
Sweave:Figures from plot (LME output) not getting generated (pdf or eps)
Hi,
I seem to be facing a strange problem when I use Sweave for creating a
LaTeX document of the R lme() output --- The EPS and PDF figure files
get created, but are empty. I have attached a reproducible example
below (taken from the R lme() help example).
------------------------------------------------------------------------------------
\documentclass[a4paper,10pt]{article}
2009 Jun 10
1
Unable to load package:lme4 [ Ubuntu 9.04 ]
Hi folks,
When I try to load package 'lme4' on my Linux box (64-bit Ubuntu
9.04), I get the following error:
-------------------------------------
> library(lme4)
Error in dyn.load(file, DLLpath = DLLpath, ...) :
function 'cholmod_start' not provided by package 'Matrix'
Error: package/namespace load failed for 'lme4'
------------------------------------
I