Displaying 20 results from an estimated 3000 matches similar to: "constrained optimization"
2005 May 22
3
constraints
Is there a package in R that handles general linear (in-)equality + box
constrained optimization?
If it is not there, could anyone advise me which way to go?
And/or point me to packages that solve these problems partially?
best, ingmar
--
Ingmar Visser
Department of Psychology, University of Amsterdam
Roetersstraat 15, 1018 WB Amsterdam
The Netherlands
http://users.fmg.uva.nl/ivisser/
tel:
2009 Nov 04
3
Constrained Optimization
Hi All,
I'm trying to do the following constrained optimization example.
Maximize x1*(1-x1) + x2*(1-x2) + x3*(1-x3)
s.t. x1 + x2 + x3 = 1
x1 >= 0 and x1 <= 1
x2 >= 0 and x2 <= 1
x3 >= 0 and x3 <= 1
which are the constraints.
I'm expecting the answer x1=x2=x3 = 1/3.
I tried the "constrOptim" function in R and I'm running into some issues.
I first start off
2004 Nov 29
3
systemfit - SUR
Hello to everyone,
I have 2 problems and would be very pleased if anyone can help me:
1) When I use the package "systemfit" for SUR regressions, I get two
different variance-covariance matrices when I firstly do the SUR
regression ("The covariance matrix of the residuals used for
estimation") and secondly do the OLS regressions. In the manual for
"systemfit" on page
2005 Nov 28
3
Looking for constrained optimisation code
_______________________________________________________________________________________
Hi,
I was just wondering if there was any available R code that could handle
general constrained optimisation problems. At the moment I'm using
nlminb and optim, both of which allow box constraints on the parameters,
but ideally I'd like to be able to specify more general constraints on
the solution
2003 Feb 20
2
is.numeric
Hi,
I have a vector, which contains both strings and numbers, e.g.
> foo <- c("str1",1234,"str2",0.9876)
I want to know if a distinct element of the vector is a string or a number and
took "is.numeric", but
> is.numeric(foo[2])
[1] FALSE
because R treats the numbers in a mixed vectors as strings:
> foo
[1] "str1" "1234"
2004 Nov 01
5
make apply() return a list
Hi,
I have a dataframe (say myData) and want to get a list (say myList) that
contains a matrix for each row of the dataframe myData. These matrices are
calculated based on the corresponding row of myData. Using a for()-loop to do
this is very slow. Thus, I tried to use apply(). However, afaik apply() does
only return a list if the matrices have different dimensions, while my
matrices have
2004 Nov 16
3
How to remove x, y labels from a plot
Hi there,
I need to plot an illustrative figure without ticks, x, y labels in R. I
managed to get the ticks removed, but had no luck with x, y labels.
Any suggestions would be much appreciated.
Jin Li
[[alternative HTML version deleted]]
2007 Oct 30
2
Splitting up the micEcon package?
Dear R Users:
The functions of our "micEcon" package [1,2] can be subdivided into three
categories:
- microeconomic demand and firm models
- sample selection models (mainly selection())
- routines for (likelihood) maximisation (e.g. maxLik(), maxNR(), maxBHHH())
(mainly used for ML estimation of sample selection models)
Although sample selection models are often used in
2005 Apr 26
2
writing a data frame in excel format
Hello
I know how read a file in excel format into a R data frame using the
RODBC library, but I don't know how write a R data frame in excel
format. I don't understand the instructions from RODBC user manual.
To read an excel file I use.
library(RODBC);
conex<-odbcConnectExcel("fis_quim.xls");
sqlTables(conex);
data<-sqlFetch(conex,"hoja1");
Suppose I
2006 Sep 28
2
R CMD build when the package name is different from the directory name
Hi,
I was really happy when I saw that in R version 2.3.0 "R CMD check" works for
packages whose package name is different from the directory name in which it
is located (see http://cran.r-project.org/src/base/NEWS).
Now, I can have branches of my packages in directories like
"[...]/branches/<version number>/", while I had to use
"[...]/branches/<version
2008 May 12
1
hessian in constrained optimization (constrOptim)
Dear helpers,
I am using the function "constrOptim" to estimate a model with ML with an
inequality constraint using the option method='Nelder-Mead'.
When I specify the option: hessian = TRUE I obtain the response:
Error in f(theta, ...) : unused argument(s) (hessian = TRUE)
I guess the function "constrOptim" does not allow this argument which, on
the other hand, is
2005 May 25
3
DOING CLUSTERING WITH THE EM ALGORITHM
Hello,
I am looking for documentation (PDF ?) about doing clustering with the EM Algorithm on R... I'm sorry for this question which may be trivial...
Thanks...
Dominique
2004 Apr 27
1
constrOptim does ineq, not eq, but who do ?
Hi everybody,
please, could you give me help ? I scanned the help archives and didn't
found hints...
I want to solve a large sparse linear system subjected to an inequality
constrains (all solutions positive) and an equality constrain (all
solutions sum to 1), thus I tried to fool constrOptim using:
x[1] + 0 + ... + 0 >= 0
...
0 + 0 + ... + x[n] >= 0
x[1] + x[2] + ... +
2004 Aug 25
1
License for including datasets in packages
Dear All,
I would like to publish a function for 'heckit' estimations together with two
examples from Greene's and Wooldridge's econometric textbooks.
These examples use the dataset of Mroz (1987) that is also available in John
Fox' "car" package. However, not all variables that are used in my examples
are available in the "car" package. Therefore, I
2009 Jul 02
2
constrained optimisation in R.
i want to estimate parameters with maximum likelihood method with contraints (contant numbers).
for example
sum(Ai)=0 and sum(Bi)=0
i have done it without the constraints but i realised that i have to use the contraints.
Without constraints(just a part-not complete):
skellamreg_LL=function(parameters,z,design)
{
n=length(z);
mu=parameters[1];
H=parameters[2];
Apar=parameters[3:10];
2004 Mar 16
2
R CMD check warning on predict.systemfit
Hi,
I added a new function "predict.systemfit" to our package "systemfit" to make
it closer to other packages (e.g. lm). Now "R CMD check" complains that the
generic function "predict" has only the argument "object", while our function
"predict.systemfit" has more arguments. However, the function "predict.lm"
has also more
2004 Sep 21
2
constrained optimization in R
R:
I need to minimize a function such that the parameters when used in
another function result in a particular value, which i fix. That is, I
need min(f(a,b)) given g(a,b)=X, where min(.) is the minimum, f(.) and
g(.) are functions (with unknown gradients) of parameters a and b and X is
a fixed value. What optimization function(s) in R do you suggest?
constrOptim looks like it will work
2004 Oct 04
7
Strange Matrix Multiplication Behaviour
Hi there fellow R-users,
Im seeing some strange behaviour when I multiply a vector by a matrix
Here is my script:
> tr
1 2 3 4 5 6
0.2217903 0.1560525 0.1487908 0.1671354 0.1590643 0.1471667
>
> ex1
a b c d e f
1 0.2309579 -3.279045 -0.6694697 -1.1024404 0.2303928 -1.5527404
2
2005 Nov 22
3
make check fails for R 2.3.0 (PR#8343)
Full_Name: Arne Henningsen
Version: 2.3.0, 2005-11-21, i686-pc-linux-gnu
OS: SuSE Linux 9.0, Kernel 2.4.21
Submission from: (NULL) (134.245.140.242)
I did not find any problems in "./configure" and "make", but "make check"
fails:
make[4]: Entering directory `/home/suapm095/Download/R-devel/tests/Examples'
collecting examples for package 'base' ...
2005 Dec 02
3
masked from package:base?
I am confused by the following description in
http://www.maths.lth.se/help/R/.R/library/systemfit/html/hausman.systemfit.html
what does the "Not run" mean? if we do not load systemfit, how can we run
the following code?
## Not run: library( systemfit )
data( kmenta )
attach( kmenta )
...
I install the package of systemfit, and run the code.
I got the warning:
> library( systemfit