uniroot REQUIRES that the function be of opposite sign at each end of the starting interval.
I won't address the other issues raised, but you can use simple stepping from a starting argument until a sign change occurs. Or you could try a different type of rootfinder, such as newtonRaphson in package pracma. There's some discussion in the (still in draft) vignette https://gitlab.com/nashjc/histoRicalg/blob/master/provenance-of-rootfinding/rootfinder.pdf by Oliver Dechant and myself as part of an investigation of "older" codes. JN On 2018-09-24 01:37 PM, Tania Morgado Garcia wrote: > Thanks for your answers. I continue to learn R and now I am detained in an > error with uniroot that I see happens to others but I can not find the > solution. Next the code > > x1 <- BAaxOrd$V1 > y1 <- BAaxOrd$V2 > x1R <- BAaxOrdRCOS$V1 > y1R <- BAaxOrdRCOS$V2 > FCOS1 <- splinefun(smooth.spline(x1,y1)) > FRCOS1 <- splinefun(smooth.spline(x1R,y1R)) > FCOS1 <- Vectorize(FCOS1) > FRCOS1 <- Vectorize(FRCOS1) > > req(input$file1) > tryCatch( > { > df <- read.csv(input$file1$datapath, > header = input$header, > sep = "\t", > quote = '"') > }, > error = function(e) { > # return a safeError if a parsing error occurs > stop(safeError(e)) > } > ) > > #if(input$disp == "head") { > # return(head(df)) > #} > #else { > > # Determine Carbon Reserve > for (row in 1:nrow(df)) { > if(df$ts==1) { > prof <- > uniroot(f=function(x){FCOS1(x1)-df$carbono},interval=c(0,20))$root > limsup <- prof + df$pu > reserva <- integrate(FRCOS1,prof,limsup)$value > } > > The if is because there are several types of soil, but I only put one. The > error is > > Warning in if (is.na(f.lower)) stop("f.lower = f(lower) is NA") : > the condition has length > 1 and only the first element will be used > Warning in if (is.na(f.upper)) stop("f.upper = f(upper) is NA") : > the condition has length > 1 and only the first element will be used > Warning: Error in uniroot: f() values at end points not of opposite sign > > The file that I load with data has a single row with the values ts = 1, > carbon = 2.04 and pu = 15 (I left only that row to be able to determine the > origin of the error). The functions FCOS1 and FRCOS1 are monotone > decreasing.Graphic attachment of FCOS1 > > I would appreciate some help in this regard > > thanks a lot > ______________________________________________ > 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.
