[R] Forcing a negative slope in linear regression?

2011-05-31 Thread J S
Dear forum members,



How can I force a negative slope in a linear regression even though the
slope might be positive?



I will need it for the purpose of determining the trend due reasons other
than biological because the biological (genetic) trend is not positive for
these data.



Thanks. Julia




Example of the data:



[1] 1.254 1.235 1.261 0.952 1.202 1.152 0.801 0.424 0.330 0.251 0.229 0.246

[13] 0.414 0.494 0.578 0.628 0.514 0.594 0.827 0.812 0.629 0.928 0.707 0.976

[25] 1.099 1.039 1.272 1.398 1.926 1.987 2.132 1.644 2.174 2.453 2.392 3.002

[37] 3.352 2.410 2.206 2.692 2.653 1.604 2.536 3.070 3.137 4.187 4.803 4.575

[49] 4.580 3.779 4.201 5.685 4.915 5.929 5.474 6.140 5.182 5.524 5.848 5.830

[61] 5.800 7.517 6.422

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[R] curve3d in emdbook package: scaling z axis?

2010-02-18 Thread J S

 
Dear R community,
 
Is there an option to assign minimum and maximum values for z axis in 3D graph 
using the function curve3d from the package emdbook? I know there are such 
options for x and y axes.
 
Thanks.
Julia

 
  
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[R] formula for degrees of freedom for nonlinear mixed model in nlme

2009-06-11 Thread J S

Dear forum members,
 
What is the formula to calculate denominator degrees of freedom (den df) for 
nonlinear mixed-effect models with covariates? My model is similar to a CO2 
uptake example from  Pinheiro and Bates (2000, page 376). In this CO2 dataset, 
there are two treatments and two types (84 observations in total), but den df 
for each parameter of the model is 64. Isn’t it too high? 
 
Your help is greatly appreciated,
Julia
 
Summary of the CO2 example:
 
 summary(fm4CO2.nlme)
Nonlinear mixed-effects model fit by maximum likelihood
  Model: uptake ~ SSasympOff(conc, Asym, lrc, c0) 
 Data: CO2 
   AIC  BIClogLik
  388.4185 420.0191 -181.2092
 
Random effects:
 Formula: list(Asym ~ 1, lrc ~ 1)
 Level: Plant
 Structure: General positive-definite, Log-Cholesky parametrization
 StdDev   Corr  
Asym.(Intercept) 2.349640 As.(I)
lrc.(Intercept)  0.079597 -0.92 
Residual 1.791962   
 
Fixed effects: list(Asym + lrc ~ Type * Treatment, c0 ~ 1) 
  Value Std.Error DF   t-value p-value
Asym.(Intercept)   41.81756  1.562426 64  26.76451  0.
Asym.TypeMississippi  -10.53045  2.208318 64  -4.76854  0.
Asym.Treatmentchilled  -2.96943  2.213172 64  -1.34171  0.1844
Asym.TypeMississippi:Treatmentchilled -10.90037  3.112220 64  -3.50244  0.0008
lrc.(Intercept)-4.55724  0.096291 64 -47.32785  0.
lrc.TypeMississippi-0.10412  0.121683 64  -0.85570  0.3954
lrc.Treatmentchilled   -0.17124  0.111959 64  -1.52953  0.1311
lrc.TypeMississippi:Treatmentchilled0.74188  0.221742 64   3.34570  0.0014
c0 50.51075  4.364727 64  11.57249  0.
 Correlation: 
  As.(I) Asy.TM Asym.T A.TM:T lr.(I) lrc.TM
Asym.TypeMississippi  -0.703   
Asym.Treatmentchilled -0.701  0.496
Asym.TypeMississippi:Treatmentchilled  0.497 -0.709 -0.711 
lrc.(Intercept)   -0.627  0.415  0.407 -0.278  
lrc.TypeMississippi0.458 -0.680 -0.322  0.482 -0.535   
lrc.Treatmentchilled   0.500 -0.351 -0.717  0.509 -0.594  0.445
lrc.TypeMississippi:Treatmentchilled  -0.262  0.375  0.362 -0.547  0.365 -0.553
c0-0.086  0.014  0.001  0.019  0.590 -0.033
  lrc.Tr l.TM:T
Asym.TypeMississippi   
Asym.Treatmentchilled  
Asym.TypeMississippi:Treatmentchilled  
lrc.(Intercept)
lrc.TypeMississippi
lrc.Treatmentchilled   
lrc.TypeMississippi:Treatmentchilled  -0.511   
c0-0.057  0.140
 
Standardized Within-Group Residuals:
Min  Q1 Med  Q3 Max 
-2.86206487 -0.49445730 -0.04217037  0.56599012  3.04061332 
 
Number of Observations: 84
Number of Groups: 12 
 
Link to the book:
http://books.google.com/books?id=N3WeyHFbHLQCpg=PA139lpg=PA139dq=mixed-effect+model+building+first+stepsource=blots=pR7PWIuKu8sig=TLhq-k5O4ZNwkBWcyQI8VZk9Umkhl=enei=1HguSrKaPJi0Nb3DnfUJsa=Xoi=book_resultct=resultresnum=1#PPA376,M1
 
 

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[R] what is this experimental design (mixed-effects model)?

2009-04-24 Thread J S

Dear R community,
 
I am wondering what experimental design I am dealing with? I study the effect 
of daily air temperature on daily body temperature of the overwintering turtles 
(i.e. sleeping in soil). The model is a cosine wave with the air temperature as 
a covariate. 
 
Objects are 19 overwintering turtles. Data were combined over the three years. 
Each turtle was studied only once during these years, while 2 turtles were 
studied during two years (see table below). The study area was the same for 
these three studied years. Turtles were overwintering in different sites within 
this area. 
 
Is that correct to treat the study years as a random effect? I understand that 
I should incorporate autocorrelation model to account for daily variations in 
turtle’s body temperature. Is there a spatial correlation between the three 
study years, since the study was done within the same area?
 
 
 
 





Study year


turtle#


2005 year

 


 

1


 

2


 

3


 

4


 

5


 

6


 

7


2006 year

 


 

8


 

9


 

0


 

11


 

12


2006 year

 


 

13


 

14


 

15


 

4


 

16


 

17


 

18


 

12


 

19
 
Thanks for your help,

Julia






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[R] Do we have to control for block in block designs if it is insignificant?

2009-03-24 Thread J S


 

I am wondering if in a block experimental design (ex. triple square lattice), 
the block effect was not significant, is it all right not to include the block 
effect in an empirical model (even though the sampling was done from different 
blocks)? Or we are forced to control for the block effect in block designs 
anyway?
 
Thanks,
Julia
 

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[R] Is this sample size big enough to test for statistical significance?

2009-03-20 Thread J S

 
 Dear R community,
 
Is this sample size large enough to study differences between two groups of the 
populations?
 
Q1: do the body temperatures differ between the two groups of the overwintering 
turtles juveniles and adults?
 
One group (adults) has 6 turtles
Second group (juveniles) has 1 turtle.
 
There are 3 replications, i.e. the experiment was repeated over the three 
years, but using different turtles. 
 
We had about 130 observations (daily body temperature) per each turtle per year.
 
I would like to test for monthly or daily differences in body temperature 
between the two groups controlling for month and year effects. I understand 
that one number of observations in the second group is not enough, but there 
are three replications and many observations per one subject.
 
Thanks.
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[R] simple for loop program for merging datasets?

2009-03-19 Thread J S

Dear R community,
 
I would like to merge two datasets based on the categorical predictor 
“country”. 
 
Dataset A:
 
Country   Measure1
Afganistan1
Afganistan1
Russia  5
Poland 3
Poland  2
 
Dataset B:
 
Country   Measure 2
Russia  2
Afganistan10
Poland  15
 
My program does not work:
 
Country_A-A$Country
Country_B-B$Country
Measure2-B$Measure2
 
for(i in 1:nrow(B)){
for(j in 1:nrow(A){
w[j]-ifelse(Country_A[j]= =(Country_B[i]),Measure2[i], NA)
}}
 
A2-cbind(B,w)
 

Thanks, Julia

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[R] Tukey, planned contrasts or t-test without ANOVA? What is correct?

2009-03-15 Thread J S

Dear R community,
 
I compare mean monthly body temperature between two age classes of turtles 
overwintering underground. 
 
lm(body_tem ~ Month*Year*Age_Class)
TukeyHSD(aov(body_tem ~ Month*Year*Age_Class, a))
 
The Tukey HSD as well as the planned contrasts method showed significant 
differences between the two age classes, but insignificant differences between 
the two age classes at the same levels of months. 
 
In the opposite, using a t-test for comparison of independent means (i.e. 
without using the ANOVA) it demonstrated insignificant differences between the 
two age classes. What result is correct?
 
Thanks,
Julia
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[R] Advice requested: Best method of coding time since repeating event

2008-08-20 Thread M-J S Milloy

Hello,

I have a dataset containing approx 1000 events spanning four years (2004.03 to 
2008.07). For each event, I'd like to determine the time (in minutes) since the 
most recent final Wednesday of the month. I've found no obvious solution on the 
list or online; I think I'll try to use functions in the chron package. 

Anyone have any other advice?

Thanks.


M-J


School of Population and Public Health,
University of British Columbia
Vancouver, Canada

Centre for Excellence in HIV/AIDS,
St. Paul's Hospital
Vancouver, Canada

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Re: [R] Test for multiple comparisons: Nonlinear model, autocorrelation?

2008-07-07 Thread J S

Thanks for your help and suggestions.
 
That’s exactly what I did, i.e. a sin () and cos () code using daily 
observations of soil temperature, and putting a variable “vegetation types” as 
a covariate. Therefore, I can build contrasts to compare parameters of the 
model such as an intercept, amplitude and phase between different vegetation 
types. 
 
If I understand correctly, you mean to do the similar model but using average 
monthly data of soil temperature instead of daily soil temperature? Still, I 
think that the model will allow us comparison of the parameters of the model 
such as an intercept, amplitude and phase between the vegetation types, but not 
the monthly soil temperature between different vegetation types…
 
Thanks for your help and I am sorry if I did not understand it correctly or did 
not describe the experiment clearly.
 
Julia Date: Sun, 6 Jul 2008 08:38:51 -0700 From: [EMAIL PROTECTED] To: 
[EMAIL PROTECTED] CC: r-help@r-project.org Subject: Re: [R] Test for multiple 
comparisons: Nonlinear model, autocorrelation?  If I had only a very limited 
time to do this, I might include  'month' as another effect, probably coded as 
'sin' and 'cos' on an  annual cycle rather than as 12 individual Indicators. 
This would allow  you to explore not only main effects but interactions with 
plots.   Before I did that, however, I'd want to generate more plots of  
data, residuals, and coefficients. For example,  qqnorm(resid(fm1Soy.nlme), 
datax=TRUE) displayed an S shape that  indicated inhomogeniety of variance. 
This suggests that there is  something else to be modeled in these data. I 
would next try plotting  residuals by 'month'. I'd also plot the averages and 
standard  deviations by 'month'. This might tell me if I only need to add a 
fixed  annual cycle, and how much of a Fourier series approximation to add. If 
 the standard deviations show a pattern, it suggests I need to model  
heteroscedasticity. For that see '?varClasses' and the corresponding  
information in a book by Pinheiro and Bates (2000), mentioned on that  help 
page. You can do 'anova' for any of these effects. [To test  changes in fixed 
effects, you will need to use method='ML', as discussed  in a book by Pinheiro 
and Bates (2000).]  Hope this helps.  Spencer  J S wrote:   Thanks. 
Here is a similar example from a book by Pinheiro and Bates   (2000, chapter 
6):  library(nlme)  data(Soybean)   fm1Soy.lis - nlsList( 
weight ~ SSlogis(Time, Asym, xmid, scal),  data = Soybean )  fm1Soy.nlme - 
nlme( fm1Soy.lis )  *If we would like to make comparisons among the 
years we could just   simply involve years as a covariate, and later we could 
use L argument   to ANOVA to could compute contrasts. *  soyFix 
- fixef( fm1Soy.nlme )  fm2Soy.nlme - update( fm1Soy.nlme,  fixed = Asym 
+ xmid + scal ~ Year,  start = c(soyFix[1], 0, 0, soyFix[2], 0, 0, soyFix[3], 
0, 0) )   * *   *My question is: How can I compare variety of soybeans 
in a separate   month, i.e. if there was a difference in weight of soybeans F 
and P in   first month, …in twelve month?*  The dataset 
“Soybean”:   Plot Variety Year Time weight   1 1988F1 F 1988 14 
0.106000   2 1988F1 F 1988 21 0.261000   3 1988F1 F 1988 28 0.666000 
  4 1988F1 F 1988 35 2.11   5 1988F1 F 1988 42 3.56   ….  
 407 1990P8 P 1990 30 1.478330   408 1990P8 P 1990 37 2.601667   409 
1990P8 P 1990 43 6.343330   410 1990P8 P 1990 51 6.131670   411 1990P8 
P 1990 64 16.411700   412 1990P8 P 1990 79 16.946700  1) 
Involving months and variety as a covariates will probably   create too many 
parameters for the model?   2) Is it possible to use some test for 
comparisons, let’s say t   test? Perhaps not in case the data are dependent 
(i.e. previous   measurement is dependent on the next measurement, i.e. there 
is   temporal correlation (as in my study of Soil temperature)? What is an  
 alternative suggestion?  Thanks,   Julia  Date: 
Fri, 4 Jul 2008 17:36:29 -0700   From: [EMAIL PROTECTED]   To: [EMAIL 
PROTECTED]   CC: r-help@r-project.org   Subject: Re: [R] Test for 
multiple comparisons: Nonlinear model,   autocorrelation? The 
question seems too general for me to offer specific suggestions. What 
problem are you trying to solve that you think 'multiple   comparisons' will 
answer? Can you produce a similar problem that is completely 
self-contained   example that eliminates complexity that may not be needed 
to understand   your question (similar to the 'Auxiliary Problem' technique 
in How to   Solve It, http://en.wikipedia.org/wiki/How_to_Solve_It)? If 
you   can, it   may lead you to a solution. If you get such an example but 
still can't   see a solution, send that example to this list (following the 
advice in   the posting guide http://www.R-project.org/posting-guide.html). 
The   simpler the example, the more likely someone on this list will reply 
  quickly with a useful suggestion. I know this doesn't solve your 
problem, but I

Re: [R] Test for multiple comparisons: Nonlinear model, autocorrelation?

2008-07-05 Thread J S

Thanks. Here is a similar example from a book by Pinheiro and Bates (2000, 
chapter 6):
 
library(nlme) data(Soybean) 
fm1Soy.lis - nlsList( weight ~ SSlogis(Time, Asym, xmid, scal),data = 
Soybean ) fm1Soy.nlme - nlme( fm1Soy.lis ) 
 
If we would like to make comparisons among the years we could just simply 
involve years as a covariate, and later we could use L argument to ANOVA to 
could compute contrasts. 
 
soyFix - fixef( fm1Soy.nlme )  fm2Soy.nlme - update( fm1Soy.nlme,fixed = 
Asym + xmid + scal ~ Year,start = c(soyFix[1], 0, 0, soyFix[2], 0, 0, 
soyFix[3], 0, 0) )
 
My question is: How can I compare variety of soybeans in a separate month, i.e. 
if there was a difference in weight of soybeans F and P in first month, …in 
twelve month?
 
The dataset “Soybean”:
  Plot Variety Year Timeweight
1   1988F1   F 1988   14  0.106000
2   1988F1   F 1988   21  0.261000
3   1988F1   F 1988   28  0.666000
4   1988F1   F 1988   35  2.11
5   1988F1   F 1988   42  3.56
….
407 1990P8   P 1990   30  1.478330
408 1990P8   P 1990   37  2.601667
409 1990P8   P 1990   43  6.343330
410 1990P8   P 1990   51  6.131670
411 1990P8   P 1990   64 16.411700
412 1990P8   P 1990   79 16.946700
 
1)  Involving months and variety as a covariates will probably create too 
many parameters for the model?
2)  Is it possible to use some test for comparisons, let’s say t test? 
Perhaps not in case the data are dependent (i.e. previous measurement is 
dependent on the next measurement, i.e. there is temporal correlation (as in my 
study of Soil temperature)? What is an alternative suggestion?
 
Thanks,
Julia Date: Fri, 4 Jul 2008 17:36:29 -0700 From: [EMAIL PROTECTED] To: 
[EMAIL PROTECTED] CC: r-help@r-project.org Subject: Re: [R] Test for multiple 
comparisons: Nonlinear model, autocorrelation?  The question seems too 
general for me to offer specific suggestions.  What problem are you trying to 
solve that you think 'multiple  comparisons' will answer?  Can you produce a 
similar problem that is completely self-contained  example that eliminates 
complexity that may not be needed to understand  your question (similar to the 
'Auxiliary Problem' technique in How to  Solve It, 
http://en.wikipedia.org/wiki/How_to_Solve_It)? If you can, it  may lead you to 
a solution. If you get such an example but still can't  see a solution, send 
that example to this list (following the advice in  the posting guide 
http://www.R-project.org/posting-guide.html). The  simpler the example, the 
more likely someone on this list will reply  quickly with a useful 
suggestion.  I know this doesn't solve your problem, but I hope it helps. 
Spencer  J S wrote:  Dear R community, I have a nonlinear model 
describing average daily soil temperature. What test should I use to compare 
differences in soil temperature of the two studied vegetation types depending 
upon month?Building linear contrasts for the developed nonlinear model 
does not help since this model does not include variable “Months” (only 
“Days”). 1) Just a Student’s test is not probably an option because I 
would violate an assumption of independency, since the daily soil temperature 
observations have high autocorrelation. Or maybe I could average the 
observations for each month and then use this test since I have observations 
for a few years, and it might overcome the problem of independency?2) 
Should I develop a second nonlinear model with months instead of days, but it 
would considerably increase a number of parameters in the model...Or: 
 3) ?Thanks for your help,  Julia  
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[R] Test for multiple comparisons: Nonlinear model, autocorrelation?

2008-07-04 Thread J S

Dear R community, 
 
I have a nonlinear model describing average daily soil temperature. What test 
should I use to compare differences in soil temperature of the two studied 
vegetation types depending upon month?
 
Building linear contrasts for the developed nonlinear model does not help since 
this model does not include variable “Months” (only “Days”). 
 
1) Just a Student’s test is not probably an option because I would violate an 
assumption of independency, since the daily soil temperature observations have 
high autocorrelation. Or maybe I could average the observations for each month 
and then use this test since I have observations for a few years, and it might 
overcome the problem of independency?
 
2) Should I develop a second nonlinear model with months instead of days, but 
it would considerably increase a number of parameters in the model...
 
Or:
3) ?
 
Thanks for your help,
Julia
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[R] mathematical expression of probability function?

2008-06-04 Thread J S

Dear R forum,
 
I have a concern regarding a mathematical expression of the probability 
function (see below). I know how to write it for only one index i, but we have 
two : i (country) and j (year). We have a set of N observations of country year 
ij (or ith country in jth year).
 
Basically, I could replace ij as a one index t and call it as a country year 
observation. Anyway, how to write this expression correctly for two indices i 
and j? Or shall we put two product signs instead?
 
The expression is similar to this:
Large Mathematical Sign of Product as a function of (Xij), 
where the low subscript of the Product is ij=1 and an upper subscript is ij=N.
 
Thanks,
Julia
 
 
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[R] Alternative options: nonlinear model autocorrelation?

2008-05-30 Thread J S
Dear R community,



Using nlme library I have developed a nonlinear mixed model. Incorporating
an autoregressive model gives me an error that I can't allocate vector of
size X. The problem is that my computer does not have enough physical memory
most probably due to a large number of observations (17,000).



I was wondering what alternative options I might use:



1)  To use ARIMA and calculate residuals, and then to apply my nonlinear
model to the residuals. I have a feeling it does not sound reasonable.

2)  If I could reduce the number of observations, my original plan would
work well and I would not have a problem with physical memory. How to reduce
the number of observations? My data consist of six sites with two plots per
site. A) To average data from two plots? It seems to me we can loose some
information; B) To model the effect of plots and remove it from the
observations, then to average the residuals for two plots within each of the
sites and apply the nonlinear model?



Your suggestions are appreciated.



Thanks,

Julia



PS: My data are daily data of soil temperature for six years, six sites and
two plots per site.

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[R] Alternative options: nonlinear model autocorrelation?

2008-05-30 Thread J S

Dear R community,
 
Using nlme library I have developed a nonlinear mixed model. Incorporating an 
autoregressive model gives me an error that I can’t allocate vector of size X. 
The problem is that my computer does not have enough physical memory most 
probably due to a large number of observations (17,000). 
 
I was wondering what alternative options I might use:
 
1)  To use ARIMA and calculate residuals, and then to apply my nonlinear 
model to the residuals. I have a feeling it does not sound reasonable. 
2)  If I could reduce the number of observations, my original plan would 
work well and I would not have a problem with physical memory. How to reduce 
the number of observations? My data consist of six sites with two plots per 
site. A) To average data from two plots? It seems to me we can loose some 
information; B) To model the effect of plots and remove it from the 
observations, then to average the residuals for two plots within each of the 
sites and apply the nonlinear model?
 
Your suggestions are appreciated. 
 
Thanks,
Julia
 
PS: My data are daily data of soil temperature for six years, six sites, two 
plots per site. 
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Re: [R] autocorrelation error: cannot allocate vector of size 220979 Kb

2008-05-18 Thread J S
Thanks. Here are some information about my computer and file:



Operating system: Windows 2000



RAM: 1.99 GB



After I run the program:

 gc()

  used (Mb) gc trigger  (Mb) max used  (Mb)

Ncells  468065 12.5 818163  21.9   818163  21.9

Vcells 1160828  8.9   46162021 352.2 54869490 418.7



 object.size(a)

[1] 2144392



 str(a)

'data.frame':   16925 obs. of  14 variables:

 $ Site  : Factor w/ 6 levels HD,LEA,MCD,..: 6 6 6 6 6 6 6 6 6 6
...

 $ Plot  : num  1 1 1 1 1 1 1 1 1 1 ...

 $ Veg   : Factor w/ 2 levels Forest,Grass: 2 2 2 2 2 2 2 2 2 2 ...

 $ Landuse   : Factor w/ 2 levels Rural,Urban: 2 2 2 2 2 2 2 2 2 2 ...

 $ Date  : Factor w/ 2484 levels 01-Apr-01,01-Apr-03,..: 1078 1162
1244 1326 1407 1488 1569 1650 1731 1812 ...

 $ Soil.temp : num  26.1 25.9 26.0 25.7 25.5 ...

 $ combin: Factor w/ 6 levels HDForestUrban,..: 6 6 6 6 6 6 6 6 6 6
...

 $ year_scale: num  -1.4 -1.4 -1.4 -1.4 -1.4 ...

 $ day   : num  14 15 16 17 18 19 20 21 22 23 ...

 $ M : num  8 8 8 8 8 8 8 8 8 8 ...

 $ year  : Factor w/ 8 levels 2000,2001,..: 4 4 4 4 4 4 4 4 4 4 ...

 $ combin2   : Factor w/ 11 levels HDForestUrban1,..: 10 10 10 10 10 10 10
10 10 10 ...

 $ time  : num  225 226 227 228 229 230 231 232 233 234 ...

 $ time_scale: num  32.8 33.8 34.8 35.8 36.8 ...




On Sat, May 17, 2008 at 5:04 PM, jim holtman [EMAIL PROTECTED] wrote:

 More information is needed.  What is your operating system?  How much RAM
 do you have?  Are there other objects in memory that you could delete to
 recover some space?  What does 'str' and 'object.size' say for the data you
 are analyzing?  What does 'gc()' report  -  you may want to do this
 before/after sections of code to see how memory might be growing.

   On Fri, May 16, 2008 at 1:56 PM, J S [EMAIL PROTECTED] wrote:

  Dear R community,



 I used a linear mixed model (named lm11) to model daily soil temperature
 depending upon vegetation cover and air temperature. I have almost 17,000
 observations for six years.



 I can not account for autocorrelation in my model, since I receive the
 error
 message after applying the function:



 update(lm11, corr=corAR1())



 Error: cannot allocate vector of size 220979 Kb



 Do you have any suggestions?



 Thanks, Julia

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 and provide commented, minimal, self-contained, reproducible code.




 --
 Jim Holtman
 Cincinnati, OH
 +1 513 646 9390

 What is the problem you are trying to solve?

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and provide commented, minimal, self-contained, reproducible code.


[R] autocorrelation in nlme: Error: cannot allocate vector of size 220979 Kb

2008-05-17 Thread J S
Dear R community,



Below you may find the details of my model (lm11). I receive the error
message Error: cannot allocate vector of size 220979 Kb after
applying the autocorrelation function update(lm11, corr=corAR1()).



lm11-lme(Soil.temp ~ Veg*M+Veg*year,

   data=a,

   random = list(Site=pdDiag(~Veg),

   Plot=pdDiag(~Veg))

Dataset:

a-data frame of daily measurements of soil temperature (Soil.temp)
over six years

Site (6 sites),

Plot(2 plots per site),

Veg(2 vegetation types: 2 sites as grassland, 4 sites as forest)

M-month (categorical predictor)

year (continues)



Thanks,

Julia

P.S. I a sorry if this message showed up a few times, since I had
trouble posting it.

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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] autocorrelation error: cannot allocate vector of size 220979 Kb

2008-05-16 Thread J S
Dear R community,



I used a linear mixed model (named lm11) to model daily soil temperature
depending upon vegetation cover and air temperature. I have almost 17,000
observations for six years.



I can not account for autocorrelation in my model, since I receive the error
message after applying the function:



update(lm11, corr=corAR1())



Error: cannot allocate vector of size 220979 Kb



Do you have any suggestions?



Thanks, Julia

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
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.


[R] autocorrelation in nlme; Error: cannot allocate vector of size

2008-05-16 Thread J S
Dear R community,



I used a linear mixed model (named lm11) to model daily soil temperature
depending upon vegetation cover and air temperature. I have almost 17,000
observations for six years.



I can not account for autocorrelation in my model, since I receive the error
message after applying the function:



update(lm11, corr=corAR1())



Error: cannot allocate vector of size 220979 Kb



Do you have any suggestions?



Thanks, Julia

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
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.


Re: [R] autocorrelation in nlme; Error: cannot allocate vector of size

2008-05-16 Thread J S
Dear R community,



Here are details of my model, which gives me trouble modeling
autocorrelation.



lm11-lme(Soil.temp ~ Veg*M+Veg*year,

   data=a,

   random = list(Site=pdDiag(~Veg),

   Plot=pdDiag(~Veg))



dataset:



a-data frame of daily measurements of soil temperature (Soil.temp) over six
years

Site (6 sites),

Plot(2 plots per site),

Veg(2 vegetation types: 2 sites as grassland, 4 sites as forest)

M-month (categorical predictor)

year (continues)



Thanks,

Julia


 Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
 Namens J S
 Verzonden: vrijdag 16 mei 2008 23:06
 Aan: r-help@r-project.org
 Onderwerp: [R] autocorrelation in nlme; Error: cannot allocate vector of
 size

 Dear R community,



 I used a linear mixed model (named lm11) to model daily soil temperature
 depending upon vegetation cover and air temperature. I have almost
 17,000
 observations for six years.



 I can not account for autocorrelation in my model, since I receive the
 error
 message after applying the function:



 update(lm11, corr=corAR1())



 Error: cannot allocate vector of size 220979 Kb



 Do you have any suggestions?



 Thanks, Julia

[[alternative HTML version deleted]]

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide
 http://www.R-project.org/posting-guide.htmlhttp://www.r-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.


[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] for loop, my program does not make a cycle

2008-05-14 Thread J S

Dear R community,
 
I wrote a small program using for loop but it does not make cycles. 
 
My data: Dataframes: a2, a1, b0 and b1. Vector: d
 
I would like to get b1 for each of i., i.e. totally 11. However, the program 
gives me b1 only for the last i =11.
 
d-as.vector(levels(a2$combin2))
for (i in 1:11){
a1-a2[a2$combin2%in%d[i],]
b1-b0[b0$Date%in%(a1$Date),]
}
  
Your help is appreciated. Maybe someone could also recommend me good literature 
on for loops in R?
 
Thanks,
Julia
_
Get Free (PRODUCT) RED™  Emoticons, Winks and Display Pics.

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and provide commented, minimal, self-contained, reproducible code.