Displaying 20 results from an estimated 3000 matches similar to: "constraints"
2005 May 20
3
constrained optimization
Hello,
I've got to compute a minimization equation under an equality constraint
(Min g(x1,x2,x3) with x1+x2=const). The Constroptim function does not
authorize an equality condition but only inequality conditions. Which
function can I use instead?
Thank you very much for your help.
Gael Robert - +33 1 42 14 27 96
******************************************************************
This
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
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]]
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
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
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
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
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 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 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
2007 Jan 11
2
Wishlist: Sweave: allow line breaks after forward slashes (PR#9444)
>>>>> On Thu, 11 Jan 2007 15:07:00 +0100 (CET),
>>>>> ahenningsen (a) wrote:
> Full_Name: Arne Henningsen
> Version: 2.4.0
> OS: Linux
> Submission from: (NULL) (134.245.140.242)
> Sweave does not allow line breaks after forward slashes ("/"). This might lead
> to a long "substring" of a command that cannot be
2004 Feb 19
6
R for economists (was: Almost Ideal Demand System)
Hi,
I did not find any web page about using R in economics and econometrics so
far. However, this does not mean that there is none (searching with google
for "R" and "economics" gives many pages about economics and a name like
Firstname R. Lastname on it ;-)).
Does anybody in the list does know such a web page?
If not, I will be happy if you, Ajay, could build and
2006 Feb 17
1
Heckman regression / adjustment for standard errors?
Hello folks,
I am trying to estimate the two-step Heckman regression model. I would like to make an adjustment for intragroup correlations. Stata can implement this with the "cluster" option, but I am really hoping to stick with R. It seems that the micEcon package is the primary source for this two-step regression model (i.e., heckit), but I can't find a way to make the
2004 Aug 19
1
sample selection problem, inverse mills ratio (Heckman, Lewbel, ...)
-----Ursprüngliche Nachricht-----
Von: Wildi Marc, wia
Gesendet: Mittwoch, 18. August 2004 10:11
An: r-help@lists.R-project.org
Betreff:
Hi
Does anybody know from an R-package devoted to sample selection problems (Heckman's lambda, Lewbel, ...)?
Thanks and best regards
Marc Wildi
[[alternative HTML version deleted]]
2004 Feb 12
1
Almost Ideal Demand System
Hi there fellow R users,
Has anyone got an R example of applying an Ideal demand system, possibly
using the library systemfit??
Thanks
Wayne
Dr Wayne R. Jones
Senior Statistician / Research Analyst
KSS Limited
St James's Buildings
79 Oxford Street
Manchester M1 6SS
Tel: +44(0)161 609 4084
Mob: +44(0)7810 523 713
KSS Ltd
Seventh Floor St James's Buildings 79 Oxford Street
2006 May 05
1
A question about linear optimizaton
Dear all,
I am trying to find a solution satisfying the below equations
in R.
Set up the problem
9 X1+ X2 + X3 = 2
X1+ X2 + X3 = 1
which is subjected to
0 < X1 < X2 < X3 < 2.
I have downloaded the packages \'linprog\' and \'lpSolve\' but can
not see how to solve the question.
Thank you for your help.
With
2006 Jul 19
1
WLS ins systemfit question
How does one specify the weights for WLS in the
systemfit command ?
That is, there is a weight option in lm(), but there
doesn't seem to be weight option for systemfit("WLS")
Thanks!
2003 Nov 17
2
Symbolic math?
Hi Folks,
I am using Windows 2000 and was wondering what (Open Source) software R
users use or might recommend for symbolic computations (aside from the ol'
noggin, e.g., Maxima, Mathomatic) .
Thanks,
Hank
Dr. Martin Henry H. Stevens, Assistant Professor
338 Pearson Hall
Botany Department
Miami University
Oxford, OH 45056
Office: (513) 529-4206
Lab: (513) 529-4262
FAX: (513) 529-4243
2004 Nov 15
1
help for nls
Hello,
I am beginning with R and I would like to test a non linear model. But I do
not find exactly wath I am looking for in nls packages (or I do not know
where to search).
I would like to try a model like this : y=b * x exp(n)/(a exp(n) + x exp
(n))
Where
a = a0 + a1z
b= b0 + b1z
x and z are variables
y the variable that I am trying to modelise
a0, a1, b0 and b1 are parameters to determine.
I