Displaying 20 results from an estimated 5000 matches similar to: "Quadratic optimization problem"
2002 Jul 23
2
tsplot
Dear all,
I would like to plot n time series together. I've defined a matrix w, where
each column contains one time series. With S-Plus usually I use the
tsplot(.) command, but it seems that this command is not available in R.
Can someone help me?
Thank you,
Enrico De Giorgi
************************************************
ETH Z?rich and
University of Z?rich
Enrico De Giorgi
Researcher
2008 Feb 15
2
Quadratic Programming
Hi,
I am using solve.QP (from quadprog) to solve a standard quadratic
programming problem: min_w -0.5*w'Qw st ... I would like solve.QP to do two
things: 1) to start the optimization from a user-supplied initial
condition; i.e., from a vector w_0 that satisfies the constraints, and 2) to
return the values of the lagrange multiplieres associated with the
constraints. I did not find an obvious
2007 Aug 17
1
Quadratic Programming
Hi there,
Is it basically possible to solve a non-convex quadratic programming with optimal solution by any way? What could be the way? How can be this problem dealt with? Could you guide me to some references please?
I thank you very much for eny help.
Tobi
---------------------------------
Boardwalk for $500? In 2007? Ha!
---------------------------------
2009 Mar 04
1
info
Dear Sir or Madam,
I've been using R for one year and I really appreciate it.
I would like to know if a version performing parallel computations on multicore computers and computer clusters exists.
Thank you very much.
Yours sincerely.
Enrico Giorgi
_________________________________________________________________
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2004 Jan 14
3
How can I test if time series residuals' are uncorrelated ?
Ok I made Jarque-Bera test to the residuals (merv.reg$residual)
library(tseries)
jarque.bera.test(merv.reg$residual)
X-squared = 1772.369, df = 2, p-value = < 2.2e-16
And I reject the null hypotesis (H0: merv.reg$residual are normally
distributed)
So I know that:
1 - merv.reg$residual aren't independently distributed (Box-Ljung test)
2 - merv.reg$residual aren't indentically
2002 Oct 21
3
Combinatorial Optimisation
Hi
I am looking to perform a discrete mean-variance optimisation, specifically to maximise the ratio of portfolio mean over portfolio standard deviation for a portfolio of several hundred stocks through discrete position size holdings in each stock, where all position sizes must be elements of a small finite set of integer amounts which include zero.
I don't think any of the standard R
2002 Oct 21
3
Combinatorial Optimisation
Hi
I am looking to perform a discrete mean-variance optimisation, specifically to maximise the ratio of portfolio mean over portfolio standard deviation for a portfolio of several hundred stocks through discrete position size holdings in each stock, where all position sizes must be elements of a small finite set of integer amounts which include zero.
I don't think any of the standard R
2003 Mar 13
1
GARCH estimation
Anyone know if there's an R package somewhere that supports estimation
of a linear regression model with GARCH error process?
There's a garch command in the tseries package, but unless I'm missing
something it is restricted to the univariate case, i.e. you can fit a
GARCH model to a single time-series but not estimate a model with
GARCH errors.
--
Allin Cottrell
Department of
2002 Nov 27
1
[No Subject]
Hi,I try to calcualte AIC or Loglik to GARCH model,But the Packege Tseries do not deal with them.How can I calculate AIC or Loglike to GARCH Model By Packege Tseries?
Thanks.
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2003 Feb 21
2
GARCH with t-innovations
Dear all,
Can garch function fit also t-innovations or only Gaussian innovations?
--
With kind regards -- Lepo pozdravljeni -- Gr??e (Gr?ezi) --
Gorazd Brumen
-------------------------------
Mail 1: gbrumen at student.ethz.ch
Mail 2: gorazd.brumen at fmf.uni-lj.si
Tel.: +41 (0)1 63 34906
Homepage: valjhun.fmf.uni-lj.si/~brumen
2003 Apr 17
2
Testing for Stationarity of time series
Hi there,
Does anyone know if R has a function for testing whether a time series is
stationary??
Thanks in advance,
Wayne
Dr Wayne R. Jones
Statistician / Research Analyst
KSS Group plc
St James's Buildings
79 Oxford Street
Manchester M1 6SS
Tel: +44(0)161 609 4084
Mob: +44(0)7810 523 713
KSS Ltd
A division of Knowledge Support Systems Group plc
Seventh Floor St James's
2007 Dec 22
1
using solve.qp without a quadratic term
I was playing around with a simple example using solve.qp ( function is in the quadprog package ) and the code is below. ( I'm not even sure there if there is a reasonable solution because I made the problem up ).
But, when I try to use solve.QP to solve it, I get the error that D in the quadratic function is not positive
definite. This is because Dmat is zero
because I don't have a
2010 Dec 04
1
Quadratic programming with semi-definite matrix
Hello.
I'm trying to solve a quadratic programming problem of the form min
||Hx - y||^2 s.t. x >= 0 and x <= t using solve.QP in the quadprog
package but I'm having problems with Dmat not being positive definite,
which is kinda okay since I expect it to be numerically semi-definite
in most cases. As far as I'm aware the problem arises because the
Goldfarb and Idnani method first
2002 Aug 05
1
Modified ARMA function
R-guRus ,
ARMA function in tseries, seems to be calculating the AR coeff 's as
coef <- lm(xx[,1]~xx[,lag$ar+1])$coef [*snipped* from around line
77,]
I'd like to modify this model with another term somewhat in these lines
lm(xx[,1] ~xx[,lag$ar+1]+mvgsignal)$coef
where mvgsignal is a moving average signal based on some indicators, the
question
is could i simply hack into
2002 Oct 01
1
High Frequency Time Series
Dear R People:
I have a weekly time series. How do I put this into the
ts command, please?
That is, what do I use for frequency, please?
R version 1.5.1 for Windows.
Thanks in advance.
Sincerely,
Erin
mailto: hodgess at uhddx01.dt.uh.edu
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r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
2003 Nov 26
3
Correlation test in time series
I would like to know if there is a way to test no correlaction
in time series ?
cov(r_t, r_t-1)=0
And r_t are homoscedastik and independent.
Thanks
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2004 Feb 03
2
How to build a AR(q)-GARCH(q) process ?
Hello all,
I would like how to modelized a time serie with AR-ARCH process.
It can be used arma and garch functions in tseries package for build
ar process or a garch process, but how can it be modelized a ar-garch
model ?
Thanks
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2004 Mar 05
2
Internal NA removal out of Time Series with na.omit.ts()
Hi R specialists,
The na.omit.ts() method fails when the time series contains internal
NA's. How can these automatically be removed?
> spectrum(ts.mNDII, na.action=na.omit)
Error in na.omit.ts(as.ts(x)) : time series contains internal NAs
How can the na.action be activated correctly?
> acf(ts.Lin, type=c("correlation"), na.action=na.omit)
Error in na.omit.ts(as.ts(x)) :
2003 Mar 28
4
Testing for randomness
Dear all,
Is there a test in R for the randomness of a sequence of observations (e.g.
to test the random number generator)? Specifically I am looking for autocorrelations
which are not necessarily linear in nature, which the acf function does
not seem to be flexible enough to detect as it tests for linear autocorrelation.
Thanks in advance,
Paul.
2003 Nov 27
2
would like to know how to simulated a GARCH(1,2)
Follow the example in tseries, we can simulated a GARCH(0,2),
n <- 1100
a <- c(0.1, 0.5, 0.2) # ARCH(2) coefficients
e <- rnorm(n)
x <- double(n)
x[1:2] <- rnorm(2, sd = sqrt(a[1]/(1.0-a[2]-a[3])))
for(i in 3:n) # Generate ARCH(2) process
{
x[i] <- e[i]*sqrt(a[1]+a[2]*x[i-1]^2+a[3]*x[i-2]^2)
}
x <- ts(x[101:1100])
and x is a GARCH(0,2).
But, I would like to know how