Displaying 20 results from an estimated 3000 matches similar to: "Algo. for matrix inverse"
2012 Dec 05
1
Understanding svd usage and its necessity in generalized inverse calculation
Dear R-devel:
I could use some advice about matrix calculations and steps that might
make for faster computation of generalized inverses. It appears in
some projects there is a bottleneck at the use of svd in calculation
of generalized inverses.
Here's some Rprof output I need to understand.
> summaryRprof("Amelia.out")
$by.self
self.time self.pct
2008 Oct 11
5
Extracting subset of a vector
I have 2 vecros :
x<-c(100,96,88,100,100,96,80,68,92,96,88,92,68,84,84,88,72,88,72,88)
x1 = sample(x, 5, replace=FALSE)
Now i want to get remaining values of vector "x" those are not member of vector "x1". Can anyone please tell me how to do that?
2008 Aug 29
1
non user-friendly error for chol2inv functions
Hi,
In function chol2inv with the option LINPACK set to false (default), it
raises an error when the matrix is 1x1 matrix (i.e. just a real) saying
'a' must be a numeric matrix
This error is raised by the underlying C function (modLa_chol2inv in
function Lapack.c). Everything is normal, but I wonder if we could have
another behavior when we pass a 1x1 matrix. I spent time this morning
2008 Mar 15
1
Fwd: Re: How to create following chart for visualizing multivariate time series
Thanks David, It is working. Holtman's also gave me a solution but, I wanted to have a color pallet for description of colors, that was not in his solution.
However I need one small modification. If I want to plot only lower diagonal elements of 'dat' then how should I proceed? What I want is, to visualize only lower diagonal elements and having the color pallet on them only. Also
2003 Oct 30
3
Change in 'solve' for r-patched
The solve function in r-patched has been changed so that it applies a
tolerance when using Lapack routines to calculate the inverse of a
matrix or to solve a system of linear equations. A tolerance has
always been used with the Linpack routines but not with the Lapack
routines in versions 1.7.x and 1.8.0. (You can use the optional
argument tol = 0 to override this check for computational
2008 Mar 15
1
How to create following chart for visualizing multivariate time series
Let me take an artifical matrix :
dat = matrix(rnorm(200*200), 200, 200)
My goal is to visualize this matrix according to the procedure, described in previous mails. I took Mendelssohn's advice and got following advice :
?plot.im
Z <- setcov(owin())
plot(Z) .................... etc
However I can not reproduce this example in my problem. How I can change my data
2007 Jun 12
3
Panel data
Dear all R users,
I have a small doubt about panel data analysis. My basic understanding on Panel data is a type of data that is collected over time and subjects. Vector Autoregressive Model (VAR) model used on this type of data. Therefore can I say that, one of statistical tools used for analysis of panel data is VAR model? If you clarify my doubt I will be very grateful.
Thanks and regards,
2009 Jul 22
6
A question on operation on list
Hi,
I have created a list object like that :
x = vector("list")
for (i in 1:5) x[[i]] = rnorm(2)
x
Now I want to do two things :
1. for each i, I want to do following matrix calculation : t(x[[i]]) %*%
x[[i]] i.e. for each i, I want to get a 2x2 matrix
2. Next I want to get x[[1]] + x[[2]] +....
I did following : res=vector("list"); res = sapply(x, function(i) t(x[[i]])
%*%
2007 May 04
2
Analysis for Binary time series
hi,
hi, good morning everyone. I have a time series with binary outputs like : 0001011110100.................etc. Now I want to forecast the future values of that. Can anyone please tell me whether there is any tools exist in literature for dealing with this kind of binary observation? If possible please provide me some good references in net as well.
rgd,
Megh
2008 Sep 17
5
Loop on vector name
[My previous message rejected, therefore I am sending same one with some modification]
I have 3 vectors with object name : dat1, dat2, dat3
Now I want to create a loop, like :
for (i in 1:3)
{
cat(sd(dati))
}
How I can do this in R?
Regards,
2010 Oct 15
7
Problem with merging two zoo objects
Dear all, I have following 2 zoo objects. However when I try to merge those 2 objects into one, nothing is coming as intended. Please see below the objects as well as the merged object:
> dat11
V2 V3 V4 V5
2010-10-15 13:43:54 73.8 73.8 73.8 73.8
2010-10-15 13:44:15 73.8 73.8 73.8 73.8
2010-10-15 13:45:51 73.8 73.8 73.8 73.8
2010-10-15 13:46:21 73.8 73.8 73.8 73.8
2009 Feb 16
5
Alternate to for-loop
Hi, I am trying to create a vector of length 10 (say), wherein each element
will be average of random sample of size 100, from a distribution, say
Normal. Can anyone please tell me without creating a "for" loop, how I can
do that?
Regards,
--
View this message in context: http://www.nabble.com/Alternate-to-for-loop-tp22035954p22035954.html
Sent from the R help mailing list archive at
2012 Nov 22
2
lapack routines cannot be loaded [Help request]
Dear BioConductor and R fellow users
I apologize in advance for double posting, but I am not sure which list would actually be best fit for this message.
I am experiencing a weird error with my R installation on Ubuntu 10.04.4 (LTS) 64bit:
When I run R on the terminal everything goes smoothly:
$R
R version 2.15.2 (2012-10-26) -- "Trick or Treat"
Copyright (C) 2012 The R Foundation
2008 Sep 09
4
Compiling date
Hi,
I have following kind of dataset (all are dates) in my Excel sheet.
09/08/08
09/05/08
09/04/08
09/02/08
09/01/08
29/08/2008
28/08/2008
27/08/2008
26/08/2008
25/08/2008
22/08/2008
21/08/2008
20/08/2008
18/08/2008
14/08/2008
13/08/2008
08/12/08
08/11/08
08/08/08
08/07/08
However I want to use R to compile those data to make all dates in same format. Can anyone please tell me any automated way
2008 Sep 10
3
How to find where is the <space> in data
I have following
" 1975 01 7711.16"
Here I need to identify where the <space> is there and then concatenate rest of the digits without <space>, i.e. I want to have "1975017711.16". Is there any R function?
Regards,
2008 Feb 29
1
Fwd: Re: How to create following chart for visualizing multivariate time series
I used ?image function to do that, like below :
require(grDevices) # for colours
x <- y <- seq(-4*pi, 4*pi, len=27)
r <- sqrt(outer(x^2, y^2, "+"))
image(x, y, r, col=gray((0:32)/32))
However my next problem to add a color pallet for color description [as shown in following link]. If anyone here tell me how to do that, it will be good for me.
Regards,
Megh Dal
2008 Sep 10
2
Woring message in as.yearmon()
I have following dataset:
> res
[,1] [,2] [,3]
[1,] 1946 4 1.27
[2,] 1946 5 1.27
[3,] 1946 6 1.27
[4,] 1946 7 1.27
[5,] 1946 8 1.52
[6,] 1946 9 1.52
[7,] 1946 10 1.52
[8,] 1946 11 1.52
[9,] 1946 12 1.62
[10,] 1947 1 1.62
[11,] 1947 2 1.62
[12,] 1947 3 1.62
[13,] 1947 4 1.87
[14,] 1947 5 1.87
[15,] 1947 6 1.87
Now I write following code
2009 Sep 13
3
How to get last day of a month?
Is there any R function to calculate automatically the last day of a
particular month? For example "sep2009" should be converted to last day of
September of 2009?
Thanks
--
View this message in context: http://www.nabble.com/How-to-get-last-day-of-a-month--tp25425645p25425645.html
Sent from the R help mailing list archive at Nabble.com.
2010 Jul 13
3
Need help on index for time series object
Dear all,
Please forgive me if there is a duplicate post; my previous mail perhaps didnt reach the list.......
Let say I have following time series
library(zoo)
> dat1 <- zooreg(rnorm(10), start=as.Date("2010-01-01"), frequency=1)
> dat1[c(3, 7,8)] = NA
> dat1
2010-01-01 2010-01-02 2010-01-03 2010-01-04 2010-01-05 2010-01-06 2010-01-07 2010-01-08 2010-01-09
2006 Nov 18
3
Random sample from log-normal distribution
Dear all R users,
Please forgive me if my question is too trivial.
Suppose I have two variables, (x,y) which is
log-normally distributed with expected value (mu1,
mu2) and some variance-covariance matrix. Now I want
to draw a random sample of size 1000 from this
distribution. Is there any function available to do
this?
Thanks and regards,
Megh