Displaying 20 results from an estimated 3000 matches similar to: "covariance"
2020 Jun 09
2
compiler-rt uses non-existent macro: __SOFT_FP__
A handful of files in compiler-rt/builtins use the macro "__SOFT_FP__". All the uses are along the same lines. Here's a representative example from compiler-rt/lib/builtins/fixdfdi.c:
#ifndef __SOFT_FP__
// Support for systems that have hardware floating-point; can set the invalid
// flag as a side-effect of computation.
...
#else
// Support for systems that don't have
2008 Jan 06
1
how to use R for Beta Negative Binomial
I think I should have posted this question here as well. I am posting my
question here since it is R related. Please see below. I originally posted
this to sci.stat.math
"Nasser Abbasi" <nma at 12000.org> wrote in message
news:Mm4gj.28843$R92.4987 at newsfe16.phx...
>
> I think R documentation is a bit hard for me to sort out at this time.
>
> I was wondering if
2008 Jan 13
2
is it safe to replace every "<-" by "=" in R code?
hi;
When I first started looking at R code, I thought that the <- notation for
assignment made the code less readable (and I still do). Then I found that
now one can use "=" in place of "<-" for assignment (I understand this
started since version 1.4). Anyway, I think using "=" makes the code much
more readable.
I was wondering, would it be safe if I
2010 Oct 13
1
bwplot change whiskers position to percentile 5 and P95
Dear R-community,
Using bwplot, how can I put the whiskers at percentile 5 and percentile 95,
in place of the default position coef=1.5??
Using panel=panel.bwstrip, whiskerpos=0.05, from the package agsemisc gives
satisfaction, but changes the appearance of my boxplot and works with an old
version of R, what I don’t want, and I didn’t find the option in
box.umbrella parameters
Many thanks
2017 Nov 28
2
variadic functions on X86_64 should (conditionally) save XMM regs even if -no-implicit-float
Specifying -no-implicit-float prevents LLVM from using non-GPR registers for purely integer operations. This is useful for operating systems (such as Wind River's VxWorks) that support tasks that do not save all registers on context switch.
This presents an interesting problem for variadic functions that may optionally take non-integer arguments (e.g. printf style functions). Should non-GPR
2010 Nov 18
3
Sample covariance matrix in R
Hello everyone.
I would like to find the sample covariance matrix using R.
So far I read on the wikipedia what a sample_covariance is
http://en.wikipedia.org/wiki/Sample_covariance
according to wikipedia one vector is enough to calculate the sample covariance matrix.
In R I tried cov(myvector) and I get the reply that I need to pass either two argument or one matrix with x,y values .
How can I
2007 Feb 06
3
How-To construct a cov list to use a covariance matrix in factanal?
Hi,
I have a set of covariance matrices but not the original data. I want to carry out some exploratory factor analysis. So, I am trying to construct a covariance matrix list as the input for factanal. I can construct a list which includes the cov, the centers, and the n.obs. But it doesn't work. I get an error that says "Error in sqrt(diag(cv)) : Non-numeric argument to mathematical
2010 Jul 19
1
Calculation of Covariance Matrix Calculation
Hi,
Excuse me for asking this silly question. But I really couldn't understand
why cov() and ccov() don't work for my calculation of covariance matrix.
a <- matrix(1:8, 2, 4)
a
[,1] [,2] [,3] [,4]
[1,] 1 3 5 7
[2,] 2 4 6 8
> ccov(a)
Error in solve.default(cov, ...) :
Lapack routine dgesv: system is exactly singular
I also tried colume bind, but it
2010 Mar 27
3
Calculate variance/covariance with complex numbers
Anybody knows what functions can be used to calculate
variance/covariance with complex numbers? var and cov don't seem to
work:
> a
1
V1 0.00810014+0.00169366i
V2 0.00813054+0.00158251i
V3 0.00805489+0.00163295i
V4 0.00809141+0.00159533i
V5 0.00813976+0.00161850i
> var(a)
1
1 1.141556e-09
Warning message:
In var(a) : imaginary parts discarded in
2008 Jun 26
2
constructing arbitrary (positive definite) covariance matrix
Dear list,
I am trying to use the 'mvrnorm' function from the MASS package for
simulating multivariate Gaussian data with given covariance matrix.
The diagonal elements of my covariance matrix should be the same,
i.e., all variables have the same marginal variance. Also all
correlations between all pair of variables should be identical, but
could be any value in [-1,1]. The problem I am
2007 Sep 26
1
Accessing the fixed- and random-effects variance-covariance matrices of an nlme model
I would appreciate confirmation that the function vcov(model.nlme)
gives the var-cov matrix of the fixed effects in an nlme model.
Presumably the random-effects var-cov matrix is given by cov(ranef
(model.nlme)?
Rob Forsyth
2012 Mar 12
3
how to calculate a variance and covariance matrix for a vector
Hello,
I have a vector {a, b1, b2, b3, b4}. How can I calculate the following
matrix:
var(a) cov(a, b1) cov(a, b2) cov(a, b3) cov(a, b4)
cov(a, b1) var(b1) cov(a, b2) cov(a, b3) cov(a, b4)
...
...
cov(a, b1) cov(a, b2) cov(a, b3) cov(a, b4) var(b4)
I would very appreciate your inputs. Thank you very much.
Sincerely,
Jialin Huang
[[alternative HTML version deleted]]
2010 Oct 18
1
Looking for covariance function -OR- how do you search
Hello everyone.,
I am looking for a covariance function this not the first time I have this type
of problem (to find which function does something). I try in google with "R cran
covariance function" but usually this ends with different results that do not
help me that much.
Could you please try to advice me how to search for what function implements the
functionality you want.
2006 Jun 02
3
lm() variance covariance matrix of coefficients.
Hi,
I am running a simple linear model with (say) 5 independent variables. Is
there a simple way of getting the variance-covariance matrix of the
coeffcient estimates? None of the values of the lm() seem to provide this.
Thanks in advance,
Ritwik Sinha
rsinha@darwin.cwru.edu
Grad Student
Case Western Reserve University
[[alternative HTML version deleted]]
2011 Apr 18
1
covariance matrix: a erro and simple mixed model question, but id not know answer sorry
Dear list
I need your help: Execuse me for my limited R knowledge.
#example data set
set.seed (134)
lm=c(1:4)
block = c(rep(lm,6))
gen <- c(rep(1, 4), rep(2, 4), rep(3, 4), rep(4, 4),rep(5, 4),rep(6, 4))
X1 = c( rnorm (4, 10, 4), rnorm (4, 12, 6), rnorm (4, 10, 7),rnorm (4, 5, 2),
rnorm (4, 8, 4), rnorm (4,7, 2))
X2 = X1 + rnorm(length(X1), 0,3)
yvar <- c(X1, X2)
X <- c(rep( 1,
2013 Mar 08
1
getting covariance ignoring NaN missing values
Hi all,
I have a matrix that has many NaN values. As soon as one of the columns has
a missing (NaN) value the covariance estimation gets thrown off.
Is there a robust way to do this?
Thanks,
Sachin
a=array(rnorm(9),dim=c(3,3))> a [,1] [,2] [,3]
[1,] -0.79418236 0.7813952 0.855881
[2,] -1.65347906 -1.9462446 -0.376325
[3,] -0.03144987 0.6756862 -1.879801>
2012 Aug 11
3
Problem when creating matrix of values based on covariance matrix
Hi,
I want to simulate a data set with similar covariance structure as my
observed data, and have calculated a covariance matrix (dimensions
8368*8368). So far I've tried two approaches to simulating data:
rmvnorm from the mvtnorm package, and by using the Cholesky
decomposition (http://www.cerebralmastication.com/2010/09/cholesk-post-on-correlated-random-normal-generation/).
The problem is
2009 Jun 02
2
variance does not equal serial covariance of lag zero?
Dear all,
Does this make any sense:
var() = cov() != acf(lag.max=0, type="covariance")?
I have daily data of IBM for May 2005, and I'm using the logarithmic return:
> ibm200505$LRAdj.Close
[1] NA 0.0203152 0.0005508 -0.0148397 -0.0025182 0.0092025
-0.0013889
[8] 0.0098196 -0.0103757 -0.0274917 0.0005716 -0.0159842 -0.0074306
0.0091710
[15] 0.0002898 0.0226306
2009 Dec 04
1
how to calculate covariance matrix in R? why cov doesn't work
Hello,
Sorry. It may be a stupid question.
I have two vectors
a<-c(9,3,5)
b<-c(3,4,1)
How can I get the variance-covariance matrix of these two vectors?
I tried cov(a,b), I got a number not a matrix.
I tried to transpose vector a and b as t(a) and t(b), it still cannot work.
Any suggestions? Thank a lot!
--
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2008 Apr 23
1
ccf and covariance
Hi.
It's my understanding that a cross-correlation function of vectors x
and y at lag zero is equivalent to their correlation (or covariance,
depending on how the ccf is defined).
If this is true, could somebody please explain why I get an
inconsistent result between cov() and ccf(type = "covariance"), but a
consistent result between cor() and ccf(type = "correlation")?
Or