Displaying 20 results from an estimated 2000 matches similar to: "Bug in optim - way to solve problem?"
2008 Aug 15
1
Strange error message from geoR´s likfit () lik. max. func.
ComRades:
I am geeting the error message
Error in ldots[[which(MET)]] : attempt to select less than one element
when I try to fit the geostatistical model with the likfit() function of
geoR.
I have tried with old data for which likfit() successfully maximised the
likelihood in previous versions of geoR, and yet the current version
fails.
I have tried in Windows Vista and Windows XP (I haven't
2013 Apr 04
5
help with kriging interpolation
All,
I am new to using R and know some basics. I wish to use kriging in R to
do the following:
given data Y =f(X1,X2,X3,.....,Xn) --1000+ irregular measured data set.
I would like to be able to get a single value y given sinle input set
(x1,x2,x3,...xn)
A google search on this takes me lierally to the same example on involving
analysis with soil sampling and I cannot figure out how to
2006 Aug 30
1
Handling realisations in geoRglm
Dear R users:
I want to model mosquito count data based on landcover attributes and
meteorological variables using a Poisson GLSM in the geoRglm package. I
have monthly mosquito counts over more than 20 years with repeated
observations from individual trap sites over time. I have used
as.geodata() to successfully read my dataset into the geodata format
utilized by geoR and geoRglm,
2010 Aug 04
1
geoR - likfit failure
Hi
I'm using geoR package to perform linear spatial interpolation(OK).
The function likfit() fails to compute REML.
The error meassage is : Error in solve.default(v$varcov, xmat);
How I can find out that likfit() is failed to process and retrieving the error message ?
Thank you so much for your help.
2012 Nov 07
2
pseudo R-squared with likfit (geoR)
We want to compute a pseudo R-squared for a model whose parameter
estimation was based on maximum likelihood (function likfit, package geoR).
I tried to compute the R2 proposed by Maddala (1983) which compare the
maximized likelihood for the model without any predictor and the
maximized likelihood for the model with all predictors.
I got a really low value (0,01%). Did I miss something? Are
2003 Sep 30
2
non-linear trends in kriging model
Hi
I am struggling to fit a non-linear trend using the
likfit function in geoR.
Specifically I want a sigmoidal function, something
like SSfpl in the nls package to fit the trend. But
it seems trend.spatial in geoR only works with lm or
glm type models.
Any ideas how I can specify the model to calculate the
kriging parameters using REML, including the
parameters of a sigmoidal trend function
2005 Nov 09
2
Variograms and large distances
Hello R list,
I need to compute empirical variograms using data from a large
geographic area (~10^6 km2). Although I could not find a specific
reference, I assume that both geoR and gstat calculate distances among
data points assuming points are on a flat surface (using the Pythagorean
Theorem). Because the location of my data is large and located near the
pole, assuming that latitude and
2006 Jan 05
1
Memory limitation in GeoR - Windows or R?
Dear Aaron,
I am really a tool user and not a tool maker (actually an ecologist
doing some biostatistics)... so, I take the liberty of sending a copy of
this e-mail to the r-help list where capable computer persons and true
statisticians may provide more relevant information and also to Paulo
Ribeiro and Peter Diggle, the authors of geoR..
I really feel that your huge matrix cannot be
2004 Sep 16
1
geoR/variog4() not returning all directions
Mac OS 10.3.5, R 2.0.0
latest version of geoR
I have an incomplete 5 x 20 spatial array of samples (60 out of 100
possible locations) for which I would like to calculate directional
variograms using variog4(). Unfortunately, I can't get it to return all
4 directions. It returns variograms for 45, 90, and 135 degrees,
omitting 0 degrees (pi/4, pi/2, 3pi/4, omitting 0). If I specify 0
2006 Jan 13
1
help with gepRglm::likfit.glsm
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch [SMTP:r-help-bounces at stat.math.ethz.ch] On Behalf Of ernesto
> Sent: Friday, January 13, 2006 9:25 AM
> To: Mailing List R
> Subject: [R] help with gepRglm::likfit.glsm
>
> Hi,
>
> I'm exploring likfit.glsm and I need some help. I have to say that I'm
> not an MCMC expert ...
>
2006 Jun 03
1
default value for cutoff in gstat variogram()
I wonder what is the default value for the argument 'cutoff' when not
specified in the variogram.formula function of gstat. Computing
variogram envelops within gstat, I am comparing the results obtained
with variog in geoR and variogram in gstat, and it took me a while
before understanding that the cutoff default value is not the maximum
distance.
Can Edzer tell us about it?
All the
2011 Mar 25
1
spatial stats - geoR - variogram - standard deviation
Hello,
I am attempting to get the standard deviation in multiple distance bins in
my spatial data.
It appears as though the 'variog' command in the geoR package will do the
trick, as one of the outputs from 'variog' is 'variog$sd', which,
according to the manual, is the "standard deviation of the values in each
bin".
However, when I run this command, the
2004 Mar 30
5
optim-Bug (PR#6720)
Full_Name: Dr. Hans A. Kestler
Version: 1.8.1.
OS: Linux, Win, Mac OSX
Submission from: (NULL) (134.60.73.116)
The code below produces after a different number of iterations i the following
error:
Error in optim(par = rep(0.5, length(edges)), loglik, method = "L-BFGS-B", :
non-finite value supplied by optim
This was reproducible on different machines (Mac G4 OSX, AMD Opteron
2005 Jun 11
1
R-help Digest, Vol 28, Issue 11
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of dwfu
> Sent: 11 June 2005 13:59
> To: r-help at stat.math.ethz.ch
> Subject: Re: [R] R-help Digest, Vol 28, Issue 11
>
>
> Dear all,
> I'm new using R and in (geo)statistics. I have a problem with solving
> my homework questions.
2003 Jul 31
1
spatial statistics vs. spatial econometrics
Dear R users,
I am putting together reading and resources lists for spatial statistics and spatial econometrics and am looking for some pointers from more experienced practitioners.
In particular, I find two "camps" in spatial modelling, and am wondering which approach is better suitied to which situation.
The first camp is along the lines of Venables and Ripley's Chapter 14
2008 Jun 26
0
geoR : Passing arguments to "optim" when using "likfit"]
Mzabalazo Ngwenya wrote:
> Hi everyone !
>
> I'm am trying to fit a kriging model to a set of data. When I just run
> the "likfit" command I can obtain the results. However when I try to
> pass additional arguements to the optimization function "optim" I get
> errors. That is I want to obtain the hessian matrix so matrix
> (hessian=TRUE).
>
2010 Nov 17
1
Please, help me with 'mattern' variogram
Hi, R-folks:
I have been tryin many combination of parameter to make Matern variogram to work, but I can't find the available one. I'm near to be crazy.
I tiped:
A?o2003Selg.lf<-likfit(A?o2003Selg,cov.model="matern",ini.cov.pars=c(1.5,14),kappa=2.5,fix.kappa=FALSE,nugget=0.08,lambda=0.008,fix.lambda=FALSE,hessian=TRUE)
the hessian shows:
$hessian
[,1]
2008 Jun 26
0
geoR : Passing arguments to "optim" when using "likfit"
Hi everyone !
I'm am trying to fit a kriging model to a set of data. When I just run the "likfit" command I can obtain the results. However when I try to pass additional arguements to the optimization function "optim" I get errors. That is I want to obtain the hessian matrix so matrix (hessian=TRUE).
Heres a little example( 1-D). Can anyone shed some light? Where am I
2012 Oct 04
1
geoRglm with factor variable as covariable
Dear R users.
I'm trying to fit a generalised linear spatial mode using the geoRglm
package. To do so, I'm preparing my data (geodata) as follow:
geoData9093 = as.geodata(data9093, coords.col= 17:18, data.col=15,*
covar.col=16*)
where covar.col is a factor variable (years in this case 90-91-92-93)).
Then I run the model as follow:
/
model.5 = list(cov.pars=c(1,1),
2008 Aug 18
1
GeoR model.control - defining covariates at prediction locations
Hi,
Im using geoR and I'm trying to do some predictions, based on an external
trend.
I'm having some problems specifying my model.control, specifically how do I
define my model, and also the source of the covariate data at the prediction
locations?
I am assuming that the covariate data at the prediction locations should be
imported to a geodata object along with the prediction location