

Hello,

 I use GAMM function (MGCV package) in R software to study relationship between pollen and pollinosis. My models include autoregressive terms. Here is an exemple:

CupAR7_2&lt;-gamm(nb_rca_2~s(Trend,bs="ps",k=49) +Semaine
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; +s(TX03,bs="ps",k=8) +s(UN03,bs="ps",k=4)&nbsp; ......+pollen01
,correlation=corARMA(p=7,q=0,form=~Trend|Annees),
niter=40,control=lmeControl(maxIter=100000,msMaxIter=100000)
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; ,family=quasipoisson, data=donnees, na=na.omit)

Each model need 1/2 hour to 1 hour to get a result and I frequently get the following error messages:

Erreur dans lme.formula(fixed = fixed, random = random, data = data, correlation = correlation,&nbsp; : 
&nbsp; nlminb problem, convergence error code = 1
&nbsp; message = singular convergence (7)

Erreur dans na.fail.default(list(Xr.4 = c(0.00374377951791214, 0.00438373736920182,&nbsp; : 
&nbsp; missing values in object


 Does my computer lack power,(if so,what is required?) or is R&nbsp; limited in speed of execution or is my syntax not ok. Here are the features of my computer:

processor: 3.10 GHz&nbsp; i5-2400 CPU
RAM: 4 Go (3.87 Go)
OS: 64 bits
Windows 7 professionnel (Pack 1)

Another question: how can we add a smoothing parameter in the model GAMM to help convergence ("sp =" is not accepted)?

Thanks for your help
Best regards

Sylvie Martin
SEPIA-Santé

Bureau d'études en épidémiologie,
biostatistiques, environnement

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