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Dear All, I'm a beginner user in R and I would like to make a quadratic and plateau model in R. Can you help please with an example? Thanks so much -- Ahmed M. Attia Assistant Lecturer El-Khattara farm Station Agronomy Dept., Zgazig Univ., Egypt Visiting Scientist Haskell Agricultural laboratory Agronomy and Horticultural Dept., Univ. of Nebraska-Lincoln ahmedatia at zu.edu.eg aattiamohamed2 at unlnotes.unl.edu Cell phone: 4023604178

The model should be class aov or lm and my model class is aovlist. tried tidy from broom library but did not work. To make it class aov, I had to remove the error term; model <- aov(Rotationdata_R$`GY(Mg/ha)`~Rep+code*as.factor(Nitrogen),data=Rotationdata_R) Ahmed Attia, Ph.D. Agronomist & Soil Scientist On Mon, Dec 25, 2017 at 7:38 PM, David Winsemius <dwinsemius at comcast.net> wrote: > >> On Dec 25, 2017, at 10:21 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: >> >> LSD.test > > ?LSD.test > No documentation...

...e 1 to date 2, dataset=1) * (biomass at date 2 -biomass at date 1, dataset = 2) + (littfall at date 2, dataset=3). all the dates are in yr-month-day format. Which library or function Should I use to tell R do these calculations of these variables at different dates. I appreciate your help. Ahmed Attia, Ph.D. Agronomist & Soil Scientist

Please help getting the R squared value in asymptotic regression model I use the code below model1<-nls(GN1~SSasymp (nrate,a,b,c), data = data.1 ) and R produced the modell coefficients without the R squared value? -- Ahmed M. Attia Research Assistant Dept. Of Soil&Crop Sciences Texas A&M University ahmed <ahmedatia@zu.edu.eg>.attia@ag.tamu.edu Cell phone: 001-979-248-5215 [[alternative HTML version deleted]]

> On Dec 25, 2017, at 2:09 PM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > > The model should be class aov or lm and my model class is aovlist. > tried tidy from broom library but did not work. To make it class aov, > I had to remove the error term; > > model <- aov(Rotationdata_R$`GY(Mg/ha)`~Rep+code*as.fac...

---------- Forwarded message ---------- From: <r-help-owner@r-project.org> Date: Mon, Jan 14, 2013 at 12:31 AM Subject: Help with nonlinear regression To: ahmedatia80@gmail.com The message's content type was not explicitly allowed ---------- Forwarded message ---------- From: Ahmed Attia <ahmedatia80@gmail.com> To: r-help@r-project.org Cc: Date: Mon, 14 Jan 2013 00:31:41 -0800 Subject: Help with nonlinear regression Hi- I have a question about nonlinear regression. *Asymptotic Regression Model** * * below is the equation of the model (Reference the R book page 662)*...

...h(odbcConnectExcel("F:\\Cotton2012\\validation.xlsx"),sqtable = "Sheet3", + na.strings = "NA", as.is = TRUE) Error in odbcConnectExcel("F:\\Cotton2012\\validation.xlsx") : odbcConnectExcel is only usable with 32-bit Windows -- Ahmed M. Attia Research Assistant Dept. Of Soil&Crop Sciences Texas A&M University ahmed <ahmedatia@zu.edu.eg>.attia@ag.tamu.edu Cell phone: 001-979-248-5215 [[alternative HTML version deleted]]

...art=2009,end = 2016, frequency =365) plot(forecast(ets(Stand_Height),10)) a=seq(as.Date("2009-12-01"),by="weeks",length=11) axis(1, at = a, labels = format(a, "%Y %b %d"), cex.axis=0.6) #Error :$ operator is invalid for atomic vectors Thanks Ahmed Attia, Ph.D. Agronomist & Soil Scientist On Fri, Jun 30, 2017 at 10:37 AM, Sarah Goslee <sarah.goslee at gmail.com> wrote: > There are a bunch of things wrong here, although without a > reproducible example I can't really fix most of them. > > - You're overwriting SH w...

...t;,type="p",cex=0.2,col=1,xaxs="i",yaxs="i",ylim=c(0,6)) axis.Date(side=3, at=seq(min(LAI_simulation$Date), max(LAI_simulation$Date),by="year"), format="%Y", xlab="xxx",cex.axis=0.9) mtext("years",side=3,line=3,cex.lab=1.2) Ahmed Attia, Ph.D. Agronomist & Soil Scientist On Wed, Jul 5, 2017 at 4:52 PM, MacQueen, Don <macqueen1 at llnl.gov> wrote: > Not entirely sure what you really want the axis on the top to look like, but here's what I'd be likely to do: > > ## note, correction to format; in your...

...ight~Date, data=Stand_Height)); dl=leafbiom$Date[i-1]; de=leafbiom$Date[i]; SH[i]=sum(SH[leafbiom$Date==de&leafbiom$Date==dl]) } SH The SH output is the prediction of Stand height in 25 observations only and provides NA for the remaining 2616 iterations. Thanks for your help. Ahmed Attia, Ph.D. Agronomist & Soil Scientist

...te that you may have to convert character strings to dates to do the above - see a function like "as.Date". Obviously I do not know the actual names of your datasets and I am assuming that the variable names you have given are the actual ones. Jim On Thu, Jun 22, 2017 at 4:19 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > Hi R users, > > I need your help to write a code in r that does the following > calculation from three different datasets; > > ac = 1/sum (NPP from date 1 to date 2, dataset=1) * (biomass at date 2 > -biomass at date 1, dataset = 2) + (...

...biggest R problem; the rest of my questions have to do with what your objective actually is, like what you are modeling and what you are doing with the predictions. But my sample code might be enough to get you headed in the right direction regardless. Sarah On Fri, Jun 30, 2017 at 9:27 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > Hi folks, > > I have 25 stand height observations over 7 years period and daily > leafbiomass data during this period. I want to use the 25 plant height > observations as inputs and predict the daily stand height during the 7 > years. >...

...ary(model) LSD.test(y=model,trt="code",console=TRUE) the error; Error in as.data.frame.default(x[[i]], optional = TRUE, stringsAsFactors = stringsAsFactors) : cannot coerce class "c("aovlist", "listof")" to a data.frame What is wrong with this. Ahmed Attia, Ph.D. Agronomist & Soil Scientist

...r-writing your variable. This time, you are overwriting the entirety of Stand_Height with the timeseries of height. Perhaps you should spend some time with one of the good introductory R resources out there, and think a bit more about your procedure. Sarah On Fri, Jun 30, 2017 at 11:23 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > Sorry for the confusion, here is the edited question. > > The data= Stand_Height (attached) is recorded from 12/1/2009 to > 12/31/2015 (25 observations) and the other dataset (leafbiom) is > recorded from 10/7/2009 to 12/29/2016 (daily observ...

...e == "i-1"]+ Litterfall_Ahmed97$littperiod[Litterfall_Ahmed97$Date =="i"])/ (sum(GPP_Ahmed13$GPP[GPP_Ahmed13$Date >= "i-1" & GPP_Ahmed13$Date <= "i"])/2) } #Error in charToDate(x) : Thanks for your help Ahmed Attia, Ph.D. Agronomist & Soil Scientist

...package to open the file and explore it's contents - you should get a clear picture of it's contents from that. Something like this (untested)... library(ncdf4) x <- nc_open(file.nc) x nc_close(x) While print lots of info about the file. Ben > On Mar 28, 2018, at 10:37 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > > Hi > > I have a netCDF file of volumetric soil water content at four > different soil layers and want to convert each soil layer in the > netCDF file to a GeoTIFF layer. This code converts the netCDF file to > one GeoTIFF layer, i.e...

> On Dec 25, 2017, at 10:21 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > > LSD.test ?LSD.test No documentation for ?LSD.test? in specified packages and libraries: you could try ???LSD.test? -- David Winsemius Alameda, CA, USA 'Any technology distinguishable from magic is insufficiently advanced.' -Gehm's...

...8 10/20/2009 0.009998 LAI_simulation$Date <- as.Date( LAI_simulation$Date, '%Y/%m/%d') plot(LAI~Date, data=LAI_simulation) LAI_simulation$Date<- as.numeric(LAI_simulation$Date,origin="2009-10-07") #R does not see the origin axis.Date(side=3,at=LAI_simulation$Date) Ahmed Attia, Ph.D. Agronomist & Soil Scientist [[alternative HTML version deleted]]

...: 0.00833333, 0.00833333 (x, y) extent : -180, 179.9998, -56, 83.99995 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0 data source : C:\Users\Ahmed\Documents\file.tif names : file values : 2, 80 (min, max) Any help! Ahmed Attia, Ph.D. Agronomist & Soil Scientist [[alternative HTML version deleted]]

<resending as I don't think I was in the mailing list yet when I sent first time... apologies if you receive this twice> Hello, I'm facing some strange behavior, and I hope you can provide a clarification. Consider the following code: virDomainPtr dom = virDomainLookupByName(virt, domain_name); if (dom) { printf("domain already