Hi there, I have a complex math equation which does not have a closed form solution. It is - y <- (p*exp(-a*d)*(1-exp((d-p)*(a-x[1]))))/((p-d)*(1-exp(-p*(a-x[1])))) For this equation, I have all the values except for x[1]. So I need to solve this problem numerically. Can anyone suggest an optimization package that I can use to estimate the value for x[1]? Thanks in advance, Diviya [[alternative HTML version deleted]]
Diviya Smith wrote:> > Hi there, > > I have a complex math equation which does not have a closed form solution. > It is - > > y <- (p*exp(-a*d)*(1-exp((d-p)*(a-x[1]))))/((p-d)*(1-exp(-p*(a-x[1])))) > > For this equation, I have all the values except for x[1]. So I need to > solve > this problem numerically. Can anyone suggest an optimization package that > I > can use to estimate the value for x[1]? >So you have data for : a, d, p and y? Define a function f <- function(x) y - (p*exp(-a*d)*(1-exp((d-p)*(a-x))))/((p-d)*(1-exp(-p*(a-x)))) and use uniroot to solve f(x) = 0 and set x[1] to the root found by uniroot. /Berend -- View this message in context: http://r.789695.n4.nabble.com/Optimization-package-tp3814296p3814747.html Sent from the R help mailing list archive at Nabble.com.
On 09/14/2011 10:37 PM, Diviya Smith wrote:> Hi there, > > I have a complex math equation which does not have a closed form solution. > It is - > > y <- (p*exp(-a*d)*(1-exp((d-p)*(a-x[1]))))/((p-d)*(1-exp(-p*(a-x[1])))) > > For this equation, I have all the values except for x[1]. So I need to solve > this problem numerically. Can anyone suggest an optimization package that I > can use to estimate the value for x[1]? > > Thanks in advance, > > Diviya > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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.Google for "R optimization". Paul -- Paul Hiemstra, Ph.D. Global Climate Division Royal Netherlands Meteorological Institute (KNMI) Wilhelminalaan 10 | 3732 GK | De Bilt | Kamer B 3.39 P.O. Box 201 | 3730 AE | De Bilt tel: +31 30 2206 494 http://intamap.geo.uu.nl/~paul http://nl.linkedin.com/pub/paul-hiemstra/20/30b/770