On Aug 24, 2015, at 7:23 AM, Jeff Newmiller wrote: > Read ?predict, paying particular attention to the newdata argument.
I agree that reading help pages is needed but need both the ?predict page and the ?integrate page. I think proximate cause of the error is that `integrate` is not getting an integrand that is a function of "x" so that it can receive a sequence of x-values and return a sequence of y-values. The interpreter is complaining because it's not getting a proper function. I suppose one could do that with predict, but you need to build that function to accept a single value as the newdata 'x'-argument. One would, of course, need to have the model name in the integrand function matching the name of the lm-object, which at the moment is also a further error waiting to be uncovered. Decided to avoid creating extraneous objects and assume that the data is in the form of a dataframe named 'inp': fitP <- lm( SOC~poly(Depth,3), data=inp ) # It's better to use correct column names with a data-argument integrand <-function(x) predict(fitP, newdata= list(Depth=x)) # single value of x passed to correct name of column, see ?predict integrate(integrand, lower = 25, upper = 80) # 7.43651 with absolute error < 8.3e-14 > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > Sent from my phone. Please excuse my brevity. > > On August 24, 2015 2:10:11 AM PDT, CarstenH <cah...@gmx.de> wrote: >> Hi all >> >> I need to calculate the area under a curve (integral) for the following >> data >> pairs: >> >> Depth SOC >> 22.5 0.143 >> 28.5 0.165 >> 34.5 0.131 >> 37.5 0.134 >> 40.5 0.138 >> 43.5 0.107 >> 46.5 0.132 >> 49.5 0.175 >> 52.5 0.087 >> 55.5 0.117 >> 58.5 0.126 >> 61.5 0.13 >> 64.5 0.122 >> 67.5 0.161 >> 71.5 0.144 >> 76.5 0.146 >> 82.5 0.156 >> 94.5 0.132 >> >> (Table name is P) >> >> After reading the data set I assiged the collumns by: >> >> /x <- (P$Depth) >> y <- (P$SOC) >> / >> >> and decided to make a ploynominal function (3rd order): >> >> /fitP <- lm( y~poly(x,3,raw=TRUE) )/ >> >> At the next step I failed. I can plot point and function but am not >> able to >> integrate the curve between e.g. depths 20 and 80. >> >> If I try: >> / >> integrand <-function(fitP1) >> predict(y) >> integrate(integrand, lower = 25, upper = 80)/ >> >> the "Conosle" opend with the message: "Source unavailable or out of >> sync" >> and >> / >> function(fitP1) >> predict(y) >> / >> ) >> >> >> Would be great if somebody could help! >> >> Thanks >> >> Carsten >> >> >> >> -- >> View this message in context: >> http://r.789695.n4.nabble.com/Calculate-the-area-under-a-curve-tp4711418.html >> Sent from the R help mailing list archive at Nabble.com. >> >> ______________________________________________ >> R-help@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. > > ______________________________________________ > R-help@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. David Winsemius Alameda, CA, USA ______________________________________________ R-help@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.
