search for: parabola

I wonder whether R has methods for constrained fitting of linear models. I am trying fm<-lm(y~x+I(x^2), data=dat) which most of the time gives indeed the coefficients of an inverted parabola. I know in advance that it has to be an inverted parabola with the maximum constrained to positive (or zero) values of x. The help pages for lm do not contain any info on constrained fitting. Does anyone know how to? Regards, Alex van der Spek

...im help page and the page in the R extensions manual giving the declaration? What do I need to change in the below to get it to work? (I also get a bus error with trace set to 0.) The source code and an example session: nmminDemo.c: #include <R_ext/Applic.h> #include <stdio.h> double parabola(int n, double *par, void *ex) { double xm = par[0] - 1; return xm * xm + 13; } int main() { double initial[1] = {1.5}; double result[1]; double value; int convergenceCode; const double abstol = 1e-16; const double reltol = 1e-8; const double alpha = 1.0; /* reflection factor */...

I'm maximising a reasonably complex function using nlme (version 3.1-65, have also tried 3.1-66) and am having trouble with fixed parameter estimates slightly away from the maximum of the log likelihood. I have profiled the log likelihood and it is a parabola but with sum dips. Interestingly changing the parameterisation moves the dips around slightly. Unfortunately the PNLS step is finding a maximum at the dips rather than the mle. I have tried using starting values for the fixed parameters without change. Any ideas ? Ken

...h is compiled under Linux (REL5). main.cpp:35: undefined reference to `Rf_initEmbeddedR(int, char**)' main.cpp:41: undefined reference to `nmmin' Thanks in advance for any help. ------------------------ #include <R_ext/Applic.h> #include <R.h> #include <stdio.h> double parabola(int n, double *par, void *ex) { double xm = par[0] - 1; return xm * xm + 13; } /* * Copied from tests/Embedded/embeddedRCall.c: */ extern int Rf_initEmbeddedR(int argc, char *argv[]); int main() { char *argv[]= {"nmminDemo", "--gui=none", "--silent"}; cons...

...e precise I wanted to start with simple higher order polynomials. Unfortunately, I do not quite understand the examples in the helpfiles for the nlm, nls and nlsModel commands. Could anyone please provide a simple example to get me started (i.e. y = p + x^2 fitted to x= -1 0 1 y = 2 1 2; a simple parabola p should turn out to be 1). How do I do this and how do I do the same for something like y = a + bx + cx^2 + dx^3 ?? Thank you very much, Christian Endter -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~horn...

How do I calculate the confidence interval for the value x given by the intersection of two quadratics (i.e. parabolas)? I fit two quadratics of the form: y = C1 + B1*x + A1*x^2 y = C2 + B2*x + A2*x^2 to two sets of points N1 and N2. I test for whether they intersect, if they do then I calculate the roots of: 0 = (C1 - C2) + (B1 - B2)*x + (A1 - A2)*x^2 to determine where they intersect and choose the pr...

Hey there, I want to plot 5 parabola functions, which happen to be f(x) = 0.25x? + 6,47x -32.6 g(x)=0.99x? -6x -195 j(x)= 0.77x? +14x -495 k(x)=0.001x? + 65x -785 l(x) = 0.9x? -2x -636 in the same graph. Sadly I even do not really understand how to plot just one graph... I found this code in the Internet, which plots a cos-fu...

...OS: Open Suse 10.0, Windows XP Submission from: (NULL) (88.134.13.50) I found a problem in the 'optimise' function for one dimensional optimisation. Example 1: Try to find a maximum of the function below with the use of 'optimise' in the interval [0,0.5]. The function follows a parabola and has two local maxima located at the margins of the interval [0,0.5]. Please try the following code which performs this optimisation, produces a plot of the function within the given interval and adds the computed maximum returned by 'optimise()' ex1 <- function(x) log(4 * x^2 - 2 *...

Dear R users, I used to "OPTIM" to minimize the obj. function below. Even though I used the true parameter values as initial values, the results are not very good. How could I improve my results? Any suggestion will be greatly appreciated. Regards, Kathryn Lord #------------------------------------------------------------------------------------------ x = c(0.35938587,

Dear R users, I used to "OPTIM" to minimize the obj. function below. Even though I used the true parameter values as initial values, the results are not very good. How could I improve my results? Any suggestion will be greatly appreciated. Regards, Kathryn Lord #------------------------------------------------------------------------------------------ x = c(0.35938587,

...;d ask you all for your thoughts. ROSENBROCK'S BANANA VALLEY FUNCTION? Beyond this, I wonder if someone help me understand the lessons one should take from Rosenbrock's banana valley function: banana <- function(x){ 100*(x[2]-x[1]^2)^2+(1-x[1])^2 } This a quartic x[1] and a parabola in x[2] with a unique minimum at x[2]=x[1]=1. Over the range (-1, 2)x(-1,1), it looks like a long, curved, deep, narrow banana-shaped valley. It is a known hard problem in nonlinear regression, but these difficulties don't affect "nlm" or "nlminb" until the hessian is...

Hi, I would like to run my monitor in Parabola OS with higher refresh rates. I'm using Nvidia 1050 Ti with nouveau drivers. Everything over 60 hz flickers. I have working settings for my panel captured from Windows settings panel (see: attachment). Could those settings help and could those be inputed to xrandr to fix flickering? -----------...

Dear R-users, I'm trying to solve the following equation, to get a set of values satisfying it and I'd like to know if its possible to do that in R. 0.85*(54.6-X)^2 + 4.65*(25.2 - Y)^2 -2*0.84*(54.6-X)*(25.2-Y) <= 8.29 Thanks a lot, Eduardo Armas --- [[alternative HTML version deleted]]

Hi  R users   I thankfull all R users for helping each other.   Could some one help me to  define data set for the following test functions: Step, Wave, Blip, Angles, Parabolas for  example , doppler function I can write dopp(n) to get data set of size n What about the functions mentioned above? [[alternative HTML version deleted]]

...iority: medium Component: Driver/nouveau AssignedTo: nouveau at lists.freedesktop.org ReportedBy: ice.cube at gmx.com QAContact: xorg-team at lists.x.org after ~5 sec to 5 min of use all freeze with or without nouveau-dri. What do you need for more explanation? Parabola GNU / Linux-libre gnome / wmii Linux-libre 3.0.4 (The computer works at this time with nv) irc :: aurelien -- Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug.

which is the purpose of this functions? _________________________________________________________________ Busca desde cualquier p?gina Web con una protecci?n excepcional. Consigue la Barra de herramientas de Windows Live hoy mismo y GRATUITAMENTE. http://www.toolbar.live.com -------------- next part -------------- An HTML attachment was scrubbed... URL:

Dear R experts, density estimation on a 2 dimensional bounded domain --------------------------------------------------------------------- I am currently trying to estimate the probability density (PD) of cancers within the breast using the sm library with the routine sm.density Of course a practical PD must be limited by the curve of the breast outline. I don't have a clue after perusing

https://bugs.freedesktop.org/show_bug.cgi?id=100167 Bug ID: 100167 Summary: nouveau sometimes doesn’t resume properly from suspend Product: xorg Version: unspecified Hardware: x86-64 (AMD64) OS: Linux (All) Status: NEW Severity: normal Priority: medium Component: Driver/nouveau

Richard Zimmerman wrote: > I've got a 3 building network... > > Buildings 1/2 between then have 3 wireless routers all pointed to one > CentOS server. > > The 3rd building across the WAN has 3 wireless routers all into one > server... > > In my case They are for local LAN access so they are setup to pint to a > single IP/gateway address... Thanks for your

https://bugs.freedesktop.org/show_bug.cgi?id=97192 Bug ID: 97192 Summary: SuperTuxkart graphic errors [NVE4 - GK104] Product: Mesa Version: unspecified Hardware: x86-64 (AMD64) OS: other Status: NEW Severity: normal Priority: medium Component: Drivers/DRI/nouveau Assignee: