Displaying 20 results from an estimated 2000 matches similar to: "eigenvalues for a sparse matrix"
2012 Mar 22
1
Simalteneous Equation Doubt in R
Hi List
l am interested in developing price model. I have found a research paper
related to price model of corn in US market where it has taken demand &
supply forces into consideration. Following are the equation:
Supply equation:
St= a0+a1Pt-1+a2Rt-1+a3St-1+a5D1+a6D2+a7D3+U1 -(1)
Where D1,D2,D3=Quarterly Dummy Variables(Since quarterly data are
considered)
Here, Supply
2007 Sep 12
1
vars package, impulse response functions ??
I am fitting a reduced form VAR model using VAR in the vars library. I have
several endogenous variables, and two exogenous variables. I would like to
explore the effects of a shock to one of the exogenous variables on one of
the endogenous variables. Using irf in the vars library only calculates the
irf for the endogenous variables, this is obviously by design, is there some
theoretical
2008 May 29
1
appropriate covariance matrix for multiple nominal exogenous and multiple continuous endogenous variables in SEM
Hi,
I would like to use the sem package to perform a path analysis (no
latent variables) with a mixture of 2 nominal exogenous, 1 continuous
exogenous, and 4 continuous endogenous variables. I seek advice as to
how to calculate the appropriate covariance matrix for use with the sem
package.
I have read through the polycor package, and am confused as to the use
of "numeric" for
2010 May 12
2
Reading R code help--Beginner
Hi, I am brand new to R and not familiar with the language, though I
have been reading the manuals and making some slow going progress. I am
working with some source code from a Global Vector Auto -Regressive
program written by Ranier Puhr from the R-forge group. I need help
interpreting the processes of the following code.
I am going to
post in parts since it's pretty long:
GVAR
2010 Jan 07
1
faster GLS code
Dear helpers,
I wrote a code which estimates a multi-equation model with generalized
least squares (GLS). I can use GLS because I know the covariance matrix of
the residuals a priori. However, it is a bit slow and I wonder if anybody
would be able to point out a way to make it faster (it is part of a bigger
code and needs to run several times).
Any suggestion would be greatly appreciated.
Carlo
2007 Mar 07
1
No fit statistics for some models using sem
Hi,
New to both R and SEM, so this may be a very simple question. I am
trying to run a very simple path analysis using the sem package.
There are 2 exogenous (FARSCH, LOCUS10) and 2 endogenous (T_ATTENT,
RMTEST) observed variables in the model. The idea is that T_ATTENT
mediates the effect of FARSCH and LOCUS10 on RMTEST. The RAM
specification I used is
FARSCH -> T_ATTENT, y1x1, NA
2006 Jul 17
1
sem: negative parameter variances
Dear Spencer and Prof. Fox,
Thank you for your replies. I'll very appreciate, if you have any ideas concerning the problem described below.
First, I'd like to describe the model in brief.
In general I consider a model with three equations.
First one is for annual GRP growth - in general it looks like:
1) GRP growth per capita = G(investment, migration, initial GRP per
2009 May 01
1
computationally singular and lack of variance parameters in SEM
Hi all,
I am trying to set up a simple path analysis in the SEM package, but I am
having some trouble. I keep getting the following error message or
something similar with my model, and I'm not sure what I'm doing wrong:
Error in solve.default(C) :
system is computationally singular: reciprocal condition number =
2.2449e-20
In addition: Warning message:
In sem.default(ram = ram, S = S,
2012 Apr 07
1
Systemfit with structural equations and cross equation parameter interaction
Hi there,
I want to estimate simultaneous equation model with panel data. The model looks as follows
Y1=a0+a1*X1+a2*X2
Y2=b0+b1*X2+b2*X1
X1=Z1-(Y1/a1)
X2=Z2-(Y2/b1)
I
In this model Y1, Y2, X1 and X2 are endogenous variables; Z1, Z2 are exogenous variables and a0, a1, a2, b0, b1 and b2 are parameters. Could any one please help me how to estimate this model in R. Thanking you in anticipation
2004 Oct 12
1
KalmanLike: missing exogenous factor?
>From the help document on KalmanLike, KalmanRun, etc.,
I see the linear Gaussian state space model is
a <- T a + R e
y = Z' a + eta
following the book of Durbin and Koopman.
In practice, it is useful to run Kalman
filtering/smoothing/forecasting with exogenous factor:
a <- T a + L b + R e
y = Z' a + M b + eta
where b is some known vector (a function of time).
Some other
2004 Sep 29
2
Approximate a f(x,y)
Hi all,
Running simulations, I'm generating market response to 2 factors X&Y..
There is no closed form for the market response.. The results are store in a
matrix Z(X <- seq(.02,.98,.02), Y <- seq(.01,.19,.01))..
For optmization purpose I need to approximate the values for any factor X in
0,02-0,98 and Y in 0,01-0,19
How can I do it ?
For one factor : Xn-1 < x <= Xn
2006 Aug 22
1
Total (un)standardized effects in SEM?
Hi there,
as a student sociology, I'm starting to learn about SEM. The course I
follow is based on LISREL, but I want to use the SEM-package on R
parallel to it.
Using LISREL, I found it to be very usable to be able to see the
total direct and total indirect effects (standardized and
unstandardized) in the output. Can I create these effects using R? I
know how to calculate them
2012 Oct 04
1
Is there any package for Vector Auto-regressive with exogenous variable other than fastVAR?
Is there any package for Vector Auto-regressive with exogenous variable other
than fastVAR?
Because it is not able to solve my problem of not taking the base in the
model.
Please suggest some appropriate solution!!!!
--
View this message in context: http://r.789695.n4.nabble.com/Is-there-any-package-for-Vector-Auto-regressive-with-exogenous-variable-other-than-fastVAR-tp4644964.html
Sent from
2011 Mar 25
4
read.xls -> rotate data.frame
Hi to all,
how could I to rotate automatically a data sheet which was imported by
read.xls?
x1 x2 x3 .... xn
y1 1 4 7 ... xn/y1
y2 2 5 8 .... xn/y2
y3 3 6 9 ....xn/y2
yn ... ... ... Xn/Yn
to
y1 y2 y3 .... yn
x1 1 2 3 ..... Yn/x1
x2 4 5 6 .... Yn/x2
x3 7 8 9 .... Yn/x2
xn ... ... ... ..... Yn/xn
Kind regards Knut
2008 Jul 23
1
Time series reliability questions
Hello all,
I have been using R's time series capabilities to perform analysis for quite
some time now and I am having some questions regarding its reliability. In
several cases I have had substantial disagreement between R and other packages
(such as gretl and the commercial EViews package).
I have just encountered another problem and thought I'd post it to the list. In
this case,
2004 Nov 03
3
fold right - recursive list (vector) operators
The programming language mosml comes with foldr that 'accumulates' a
function f over a list [x1,x2,...,xn] with initial value b as follows
foldr f b [x1,x2,...,xn] = f(x1,...,f(xn-1,f(xn,b))...)
Observe that "list" should have same elements so in R terminology it would
perhaps be appropriate to say that the accumulation takes place over a
'vector'.
I wonder if R
2012 Apr 16
1
eval a SYMSXP from C
Can someone offer some advice on how to properly evaluate a SYMSXP
from a .Call ?
I have the following in R:
variable xn, with an attribute "mu" which references the variable mu
in the global environment.
I know "references" is a loose term; mu was defined in this fashion as
a way to implement deferred binding:
foo <- function(x,mu) {
attr(x,"mu") <-
2006 Dec 20
2
Kalman Filter in Control situation.
I am looking for a Kalman filter that can handle a control input. I thought
that l.SS was suitable however, I can't get it to work, and wonder if I am
not using the right function. What I want is a Kalman filter that accepts
exogenous inputs where the input is found using the algebraic Ricatti
equation solution to a penalty function. If K is the gain matrix then the
exogenous input
2017 Dec 03
5
Rcpp, dyn.load and C++ problems
Hi,
I have written a small C++ function and compile it.
However in R I can't see the function I have defined in C++.
I have read some web-pages about Rcpp and C++ but it is a bit confusion
for me.
Anyway,
This is the C++-code:
#include <Rcpp.h>
using namespace Rcpp;
// [[Rcpp::export]]
List compute_values_cpp(int totalPoints = 1e5, double angle_increment =
0.01, int radius =
2015 Jul 28
2
all.equal: possible mismatch between behaviour and documentation
Dear all,
The documentation for `all.equal.numeric` says
Numerical comparisons for ?scale = NULL? (the default) are done by
first computing the mean absolute difference of the two numerical
vectors. If this is smaller than ?tolerance? or not finite,
absolute differences are used, otherwise relative differences
scaled by the mean absolute difference.
But the actual behaviour