similar to: non linear models

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

Hi, I'm trying to get a toy program making use of nmmin to run successfully. I've gotten to the point of compiling. However, when I attempt to run my executable, I guess a bus error. I see that someone else has asked about using nmmin before <http://tolstoy.newcastle.edu.au/R/help/06/03/23944.html>, but I haven't come across any replies. Is there some documentation on how to

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

I am trying to use the R API to call optim functions (nmmin, vmmin, lbfgsb, etc.) through a C program but I couldn't find the shared library to link under the R-2.6.0 build which 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. ------------------------

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,

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-function: >x <- seq( -10, 10, length = 1000) >plot(x,

Full_Name: Karsten Krug Version: 2.4.0 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

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-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]]

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:

GENERAL REFERENCE ON NONLINEAR OPTIMIZATION? What are your favorite references on nonlinear optimization? I like Bates and Watts (1988) Nonlinear Regression Analysis and Its Applications (Wiley), especially for its key insights regarding parameter effects vs. intrinsic curvature. Before I spent time and money on several of the refences cited on the help pages for "optim",

Dear ReXperts, I have the below text file output. I need to extract the T, QC, QO, QO-QC and WT columns for the data between T = 10 and T=150. Any ideas? Thanks in advance. ======================================================================================== 1 D C ---CAT-- T THETA QC QO QO-QC QC/QO WT FSD 8 1 0 1.0000E+01

Dear friends - occurring in Windows R2.6.2 I am modeling physical chemistry in collaboration with a friend who has preferred working in Excel. I used uniroot, and find a solution to a two buffer problem in acid-base chemistry which I believe is physiologically sensible. Using "goal seek" in Excel my friend found another plausible root, quite close to zero, and a plot of the function

Hi all, how can I divide two tables of the same dimension so that all names are preserved, ie do not become NA? I have "tab1" and "tab2", each having names in the first column. I want "tab3" with the same names and values "tab1/tab2". Thanks, Serguei

dear R users, the data frame (read in from a csv) looks like this: TreeTag Census Stage DBH 1 CW-W740 2001 juvenile 5.8 2 CW-W739 2001 juvenile 4.3 3 CW-W738 2001 juvenile 4.7 4 CW-W737 2001 juvenile 5.4 5 CW-W736 2001 juvenile 7.4 6 CW-W735 2001 juvenile 5.4 ... 1501 1.00E-20 2001 adult 32.5 i would like to

Hello, We use drc to fit dose-response curves, recently we discovered that there are quite different standard error values returned for the same dataset depending on the drc-version / R-version that was used (not clear which factor is important) On R 2.9.0 using drc_1.6-3 we get an IC50 of 1.27447 and a standard error on the IC50 of 0.43540 Whereas on R 2.7.0 using drc_1.4-2 the IC50 is