Sorry I made a copy and paste error. To get all the details of the curves between 0 and I had to use:
E <- seq(0,10, len = 2000) Sorry for the inconvenience. Yours sincerely / Med venlig hilsen Frede Aakmann Tøgersen Specialist, M.Sc., Ph.D. Plant Performance & Modeling Technology & Service Solutions T +45 9730 5135 M +45 2547 6050 fr...@vestas.com http://www.vestas.com Company reg. name: Vestas Wind Systems A/S This e-mail is subject to our e-mail disclaimer statement. Please refer to www.vestas.com/legal/notice If you have received this e-mail in error please contact the sender. > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf Of Frede Aakmann Tøgersen > Sent: 23. april 2014 10:54 > To: Andras Farkas; r-help@r-project.org > Subject: Re: [R] finding value for a parameter in an equation > > Hi Andras > > I suppose you want to find the real root of your equation if such exists for > the particular settings of the parameters. For that you can use uniroot(). > > So define a function based on your equation like this: > > f <- function(E, D1, D2, IC501, IC502, ECON, ALPHA, M1, M2){ > 1 - D1/(IC501*((E/(ECON-E))^(1/M1)))+D2/(IC502*((E/(ECON-E))^(1/M2))) > + > (ALPHA*D1*D2)/(IC501*IC502*((E/(ECON-E))^(0.5/M1+0.5/M2))) > } > > Now do some plotting to see how the functions behaves: > > ## Parameters > D1 <-c(0.2,0.6,0.8) > D2 <-c(114,190,304) > IC501 <-0.62 > IC502 <-137.8 > ECON <-5.95 > ALPHA <-0.00005 > M1 <-0.84 > M2 <-0.96 > > # vector for E > E <- seq(1,15, len = 100) > > ## three curves for each set of values of D1 and D2 > plot(E, f(E, D1[1], D2[1], IC501, IC502, ECON, ALPHA, M1, M2), type = "l", > col = > "red") > lines(E, f(E, D1[2], D2[2], IC501, IC502, ECON, ALPHA, M1, M2), type = "l", > col > = "green") > lines(E, f(E, D1[3], D2[3], IC501, IC502, ECON, ALPHA, M1, M2), type = "l", > col > = "blue") > > f() is only defined on the open interval (0;6). > > Attached figure shows that there is real roots for the 3 values of D1 and D2 > somewhere between 0 and 1. > > And those can be found as > > > uniroot(f, c(0.0001,1), D1=D1[1], D2=D2[2], IC501=IC501, IC502=IC502, > ECON=ECON, ALPHA=ALPHA, M1=M1, M2=M2) > $root > [1] 0.0003440589 > > $f.root > [1] 21.33889 > > $iter > [1] 14 > > $init.it > [1] NA > > $estim.prec > [1] 6.103516e-05 > > > uniroot(f, c(0.0001,1), D1=D1[2], D2=D2[2], IC501=IC501, IC502=IC502, > ECON=ECON, ALPHA=ALPHA, M1=M1, M2=M2) > $root > [1] 0.3840484 > > $f.root > [1] -9.45929e-05 > > $iter > [1] 9 > > $init.it > [1] NA > > $estim.prec > [1] 6.103516e-05 > > > uniroot(f, c(0.0001,1), D1=D1[3], D2=D2[3], IC501=IC501, IC502=IC502, > ECON=ECON, ALPHA=ALPHA, M1=M1, M2=M2) > $root > [1] 0.1476688 > > $f.root > [1] -0.001927616 > > $iter > [1] 9 > > $init.it > [1] NA > > $estim.prec > [1] 6.103516e-05 > > > > > > > uniroot(f, c(0.0001,1), D1=D1[2], D2=D2[2], IC501=IC501, IC502=IC502, > ECON=ECON, ALPHA=ALPHA, M1=M1, M2=M2) > $root > [1] 0.3840484 > > $f.root > [1] -9.45929e-05 > > $iter > [1] 9 > > $init.it > [1] NA > > $estim.prec > [1] 6.103516e-05 > > But > > > > > Yours sincerely / Med venlig hilsen > > > Frede Aakmann Tøgersen > Specialist, M.Sc., Ph.D. > Plant Performance & Modeling > > Technology & Service Solutions > T +45 9730 5135 > M +45 2547 6050 > fr...@vestas.com > http://www.vestas.com > > Company reg. name: Vestas Wind Systems A/S > This e-mail is subject to our e-mail disclaimer statement. > Please refer to www.vestas.com/legal/notice > If you have received this e-mail in error please contact the sender. > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] > > On Behalf Of Andras Farkas > > Sent: 22. april 2014 21:33 > > To: r-help@r-project.org > > Subject: [R] finding value for a parameter in an equation > > > > Dear All, > > > > please provide some insights for the following: > > > > we have: > > > > D1 <-c(0.2,0.6,0.8) > > D2 <-c(114,190,304) > > IC501 <-0.62 > > IC502 <-137.8 > > ECON <-5.95 > > ALPHA <-0.00005 > > M1 <-0.84 > > M2 <-0.96 > > > > and the equation: > > > > 1 = D1/(IC501*((E/(ECON-E))^(1/M1)))+D2/(IC502*((E/(ECON- > > E))^(1/M2)))+(ALPHA*D1*D2)/(IC501*IC502*((E/(ECON- > > E))^(0.5/M1+0.5/M2))) > > > > In this equation the value for parameter "E" is what I am trying to > > calculate > > (all other parameters are known) for each pairs of D1 and D2 (ie: input > D1[1] > > and D2[1] and the rest of the parameters first then substitute D1[2] and > > D2[2], then substitute D1[3] and D2[3]). It seems as if the equation can not > > be re-arranged so that "E" could be directly calculated, so looking to see > > if > > you could help me perhaps with a thought on how this could be solved with > > R, > > > > thanks as always, > > > > Andras > > [[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.
