Displaying 9 results from an estimated 9 matches for "q_i".
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_i
2006 May 08
2
On the speed of apply and alternatives?
...lowing code :
# generate a (1000 x 10001) matrix, testm
# generate statistics matrix 1000 x 4:
qnt <- c(0.01, 0.05)
cmp_fun <- function(x)
{
LAST <- length(x)
smpls <- x[1:(LAST-1)]
real <- x[LAST]
ret <- vector(length=length(qnt)*2)
for (i in 1:length(qnt))
{
q_i <- quantile(smpls, qnt[i]) # the quantile i
m_i <- mean(smpls[smpls<q_i ] ) # mean of obs less than q_i
ret[i] <- ifelse(real < q_i, 1, 0)
ret[length(qnt)+i] <- ifelse(real < q_i, real - m_i, 0)
}
ret
}
hcvx <- apply(testm, 1, cmp_fun)
The c...
2001 Feb 15
2
deviance vs entropy
Hello,
The question looks like simple. It's probably even stupid. But I spent several hours
searching Internet, downloaded tons of papers, where deviance is mentioned and...
And haven't found an answer.
Well, it is clear for me the using of entropy when I split some node of a classification tree.
The sense is clear, because entropy is an old good measure of how uniform is distribution.
2005 Aug 14
1
complex expression with plotmath
...into the
title of a plot.
My best attempt is the following:
myplot <- function(var1, var2) {
v=paste(var1,"==1 & ",var2,"==2");
plot(1:10, main=parse(,,v))
}
But when I call it with something like myplot("Q[i]", "Delta[j]") I
get "&(Q_i=1,Delta_j=2)" as title when I want to get "Q_i=1 &
Delta_j=2".
Is there any solution within R? (I don't want to use psfrag and Latex
to post-process the plot)
Why R does not have support for full Latex expressions? (as Matlab
f.ex.). IMHO plotmath is not good enough.
Thank...
2011 Nov 19
1
wald test: compare quantile regression estimators from different samples
Dear all,
I am trying to compare the estimated coefficients of a quantile regression model between two different samples. It is a Wald test, but I cannot find one way to do that in R.The samples are collected conditional on a specific characteristic and I would like to test whether such characteristic indeed affect the estimators. The problem in the test anova.rq is that the response variable
2007 Apr 24
1
Matrix: how to re-use the symbolic Cholesky factorization?
...repeated Cholesky
factorization of a spares symmetric matrices, say Q_1, Q_2, ...,Q_n,
where the Q's have the same non-zero pattern. I know in this case one
does only need to carry out the symbolic factorization _once_ and
then follow that up with a numerical factorization for each of the
Q_i's (re-using the general symbolic factorization each time). Does
anybody know if this is possible using the Matrix package?
Thanks,
Gardar Johannesson
Lawrence Livermore National Laboratory
2004 Feb 03
1
Stereo mode settings
Hi everyone,
I'd like a bit of information about the stereo mode settings in
psych_44.h of libvorbis. Specifically, about the adj_stereo structure:
typedef struct {
int pre[PACKETBLOBS];
int post[PACKETBLOBS];
float kHz[PACKETBLOBS];
float lowpasskHz[PACKETBLOBS];
} adj_stereo;
What I am attempting to do is bring lossless stereo coupling down to the
lower quality levels in
2018 Feb 02
1
R-gui sessions end when executing C-code
...while(iter < maxIter && not_converged)
{
/* make v_ij + (1-mu)*ln(q_ij) */
for (j=0; j<H_c; j++)
{...
2006 Dec 02
2
nonlinear quantile regression
Hello, I?m with a problem in using nonlinear quantile regression, the
function nlrq.
I want to do a quantile regression o nonlinear function in the form
a*log(x)-b, the coefficients ?a? and ?b? is my objective. I try to use the
command:
funx <- function(x,a,b){
res <- a*log(x)-b
res
}
Dat.nlrq <- nlrq(y ~ funx(x, a, b), data=Dat, tau=0.25, trace=TRUE)
But a can?t solve de problem,
2007 Apr 14
6
[LLVMdev] Regalloc Refactoring
On Thu, 12 Apr 2007, Fernando Magno Quintao Pereira wrote:
>> I'm definitely interested in improving coalescing and it sounds like
>> this would fall under that work. Do you have references to papers
>> that talk about the various algorithms?
>
> Some suggestions:
>
> @InProceedings{Budimlic02,
> AUTHOR = {Zoran Budimlic and Keith D. Cooper and Timothy