> On 26 Aug 2017, at 14:18, Ulrik Stervbo <ulrik.ster...@gmail.com> wrote: > > Please keep the list in cc. > > Sorry, it didn't work as expected. Maybe someone else have an appropriate > solution. > > Best, > Ulrik > > On Sa., 26. Aug. 2017, 12:57 niharika singhal <niharikasinghal1...@gmail.com> > wrote: > >> Hi >> >> Thanks for you mail, >> I really appreciate your time on my problem >> >> I have posted this problem on >> >> >> https://stats.stackexchange.com/questions/299590/to-find-maxima-for-gaussian-mixture-model >> >> >> The plot I am getting using UnivarMixingDistribution from distr package in >> R >> >> code is >> >> mc0= c(0.1241933, 0.6329082 <06329%20082>, 0.2428986 <02428%20986>) >> rv >> <-UnivarMixingDistribution(Norm(506.8644,61.02859),Norm(672.8448,9.149168),Norm( >> 829.902,74.84682), mixCoeff=mc0/sum(mc0)) >> plot(rv, to.draw.arg="d") >> >> I want output around 672 in first case and in 2nd case around 2.1 >> according to the plot. >> your code will not work in both the scenario >> >> Regards >> Niharika Singhal >> >> >> On Sat, Aug 26, 2017 at 12:47 PM, Ulrik Stervbo <ulrik.ster...@gmail.com> >> wrote: >> >>> Hi, >>> >>> I once found this somewhere on stackoverflow: >>> >>> values <- rnorm(20, mean = c(2.15,2.0,2.9), sd = c(0.1,0.1,0.1)) >>> >>> v_dens <- density(values) >>> v_dens_y <- v_dens$y >>> >>> r <- rle(v_dens_y) >>> # These functions ignore the extremes if they are the first or last point >>> maxima_index <- which(rep(x = diff(sign(diff(c(-Inf, r$values, -Inf)))) >>> == -2, times = r$lengths)) >>> minima_index <- which(rep(x = diff(sign(diff(c(-Inf, r$values, -Inf)))) >>> == 2, times = r$lengths)) >>> >>> plot(v_dens_y) >>> >>> HTH >>> Ulrik >>> >>> >>> On Sat, 26 Aug 2017 at 11:49 niharika singhal < >>> niharikasinghal1...@gmail.com> wrote: >>> >>>> I have a Gaussian mixture model with some parameters >>>> >>>> mean=(506.8644,672.8448,829.902) >>>> >>>> sigma=(61.02859,9.149168,74.84682) >>>> >>>> c=(0.1241933, 0.6329082 <06329%20082>, 0.2428986 <02428%20986>) >>>> >>>> And the plot look something like below.[image: enter image description >>>> here] >>>> <https://i.stack.imgur.com/4uUQ9.png> >>>> >>>> Also, if I change my parameters to >>>> >>>> mean=(2.15,2.0,2.9) >>>> >>>> sigma=(0.1,0.1,0.1) >>>> >>>> c=(1/3,1/3,1/3) >>>> >>>> Then plot would change to[image: enter image description here] >>>> <https://i.stack.imgur.com/kESYX.png> >>>> >>>> Is there any way to find the maxima. I have tried Newton's method but it >>>> gave me the wrong output. >>>> >>>> Like in general some common solution, which would work on all the cases, >>>> is >>>> needed.Can someone suggest me how can I achieve this >>>> >>>> Thanks in advance >>>> >>>> Niharika Singhal >>>> >>>> [[alternative HTML version deleted]] >>>> >>>> ______________________________________________ >>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>>> https://stat.ethz.ch/mailman/listinfo/r-help >>>> PLEASE do read the posting guide >>>> http://www.R-project.org/posting-guide.html >>>> and provide commented, minimal, self-contained, reproducible code. >>>> >>> >>
See the solution below if it helps. Also please, create a minimal reproduciple example as I did. So, we can investigate easily on your real problem. set.seed(1) m <- c(506.8644, 672.8448, 829.902) sig <- c(61.02859, 9.149168, 74.84682) x1 <- density(rnorm(500, mean = m, sd = sig)) plot(x1) fun <- splinefun(x = x1$x, y = x1$y, method = "n") optimize(fun, interval = range(x1$x), maximum = TRUE) m <- c(2.15, 2.0, 2.9) sig <- c(0.1,0.1,0.1) x2 <- density(rnorm(500, mean = m, sd = sig)) plot(x2) fun <- splinefun(x = x2$x, y = x2$y, method = "n") optimize(fun, interval = range(x2$x), maximum = TRUE) ______________________________________________ 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.
