LEPREVOST Florian (SNCF / DIR TECHNOLOGIES INNOVATION ET PROJETS GROUPE / IR DIR RECHERCHE -MEV)
2022-Oct-28 12:52 UTC
[R] NLME regression with weights, syntax in r
Hi all,
I found this (very) old post which had a similar problem but went without an
answer (https://stat.ethz.ch/pipermail/r-help/2004-October/058325.html)
I am trying to fit a power curve to model some observations in an nlme. However,
I know some observations to be less reliable than others (reliability of each
OBSID reflected in the WEIV in the dummy data), relatively independent of
variance, and I quantified this beforehand and wish to include it as weights in
my model. Moreover, I know a part of my variance is correlated with my
independent variable so I cannot use directly the variance as weights.
This is my model:
coeffs_start = lm(log(DEPV)~log(INDV), filter(testdummy10,DEPV!=0))$coefficients
nlme_fit <- nlme(DEPV ~ a*INDV^b,
data = testdummy10,
fixed=a+b~ 1,
random = a~ 1,
groups = ~ PARTID,
start = c(a=exp(coeffs_start[1]), b=coeffs_start[2]),
verbose = F,
method="REML",
weights=varFixed(~WEIV))
This is some sample dummy data (I know it is not a great fit but it's fake
data anyway) :
https://github.com/FlorianLeprevost/dummydata/blob/main/testdummy10.csv
This runs well without the "weights" argument, but when I add it I get
this error and I am not sure why because I believe it is the correct syntax:
Error in recalc.varFunc(object[[i]], conLin) :
dims [product 52] do not match the length of object [220]
In addition: Warning message:
In conLin$Xy * varWeights(object) :
longer object length is not a multiple of shorter object length
Thanks in advance!
Best
Florian
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1. No data, so may be impossible to help. Can you provide a minimal REPREX? 2. But probably better posted on r-sig-mixed-models anyway if you don't get a useful answer here. Cheers, Bert On Sun, Oct 30, 2022 at 3:20 AM LEPREVOST Florian (SNCF / DIR TECHNOLOGIES INNOVATION ET PROJETS GROUPE / IR DIR RECHERCHE -MEV) <f.leprevost at sncf.fr> wrote:> Hi all, > > I found this (very) old post which had a similar problem but went without > an answer (https://stat.ethz.ch/pipermail/r-help/2004-October/058325.html) > > I am trying to fit a power curve to model some observations in an nlme. > However, I know some observations to be less reliable than others > (reliability of each OBSID reflected in the WEIV in the dummy data), > relatively independent of variance, and I quantified this beforehand and > wish to include it as weights in my model. Moreover, I know a part of my > variance is correlated with my independent variable so I cannot use > directly the variance as weights. > > This is my model: > > coeffs_start = lm(log(DEPV)~log(INDV), > filter(testdummy10,DEPV!=0))$coefficients > > > > nlme_fit <- nlme(DEPV ~ a*INDV^b, > > data = testdummy10, > > fixed=a+b~ 1, > > random = a~ 1, > > groups = ~ PARTID, > > start = c(a=exp(coeffs_start[1]), b=coeffs_start[2]), > > verbose = F, > > method="REML", > > weights=varFixed(~WEIV)) > > This is some sample dummy data (I know it is not a great fit but it's fake > data anyway) : > https://github.com/FlorianLeprevost/dummydata/blob/main/testdummy10.csv > > This runs well without the "weights" argument, but when I add it I get > this error and I am not sure why because I believe it is the correct syntax: > > Error in recalc.varFunc(object[[i]], conLin) : > > dims [product 52] do not match the length of object [220] > > In addition: Warning message: > > In conLin$Xy * varWeights(object) : > > longer object length is not a multiple of shorter object length > > Thanks in advance! > > > > Best > > Florian > > ------- > Ce message et toutes les pi?ces jointes sont ?tablis ? l'intention > exclusive de ses destinataires et sont confidentiels. L'int?grit? de ce > message n'?tant pas assur?e sur Internet, la SNCF ne peut ?tre tenue > responsable des alt?rations qui pourraient se produire sur son contenu. > Toute publication, utilisation, reproduction, ou diffusion, m?me partielle, > non autoris?e pr?alablement par la SNCF, est strictement interdite. Si vous > n'?tes pas le destinataire de ce message, merci d'en avertir imm?diatement > l'exp?diteur et de le d?truire. > ------- > This message and any attachments are intended solely for the addressees > and are confidential. SNCF may not be held responsible for their contents > whose accuracy and completeness cannot be guaranteed over the Internet. > Unauthorized use, disclosure, distribution, copying, or any part thereof is > strictly prohibited. If you are not the intended recipient of this message, > please notify the sender immediately and delete it. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]