Displaying 20 results from an estimated 4000 matches similar to: "Exponent of sqr symmetric matrix"
2008 Apr 05
2
Adding a Matrix Exponentiation Operator
Hi all
I recently started to write a matrix exponentiation operator for R (by
adding a new operator definition to names.c, and adding the following code
to arrays.c). It is not finished yet, but I would like to solicit some
comments, as there are a few areas of R's internals that I am still feeling
my way around.
Firstly:
1) Would there be interest in adding a new operator %^% that performs
2012 May 07
1
Value of Hurst exponent (R/S) method > 1
Hello,
I'm using fArma package to estimate the value of Hurst exponent using R/S
method. However, for a certain set of data I get H ~ 1.8. How do I
interpret this?
Following are the output that I get for this set:
> mean(data[,2])
[1] 400.5433
> sd(data[,2])
[1] 1139.786
>
> rsFit(data[,2], levels = 64)
Title:
Hurst Exponent from R/S Method
Call:
rsFit(x = data[, 2], levels
2012 Jun 22
2
Boxplot with Log10 and base-exponent axis
Dear all,
I would like to (i) produce boxplot graphs with axis in logarithm in base 10
and (ii) showing the values on the axis in 10^exponent format rather than
10E+exponent.
To illustrate with an example, I have some widely spread data that I chart
plot using boxplot() [figure on the left]; the log="y" option of boxplot()
I obtained the natural logarithm conversion of the data and
2009 Mar 23
3
Replacing a few variable values within a DataFrame...
I would like to replace a few varaibles within a data frame.
For example, in the dataframe below (contrived) I would like to replace the current housesize value only if the Location is HSV. However, I would like to leave the other values intact.
I tried "ifelse", but I don't really need the else condition.
test_data2_df<-data.frame(Variables=c("SQR
2005 Jun 15
1
coding to generate a matrix to prepare for chi-sqr test f or text mining
I would compile a table of all the words in the dataset (maybe you have it
already), then create a list where each component is an integer vector of
indices of words. That is, replace words by their positions in the table.
>From that sparse form you could create binary features to use with standard
classification methods, or for example compute the X'X matrix for linear
regression
2010 Jul 19
1
Hurst Exponent Estimation
Dear All,
I am a novice when it comes to time-series analysis and at the moment I
am actually interested in calculating the Hurst exponent of a time
series.
This question has already been asked quite some time ago
http://bit.ly/98dZsi
and I trust some progress has been made ever since.
I was able to find some functions in the packages
http://cran.r-project.org/web/packages/Rwave/index.html
2004 Mar 05
3
Lyapunov exponent code for time series
Dear all,
Has anyone worked on coding for calculating Lyapunov Exponent for a time
series data? or any package is available for computing Lyapunov?
Please advice and many thanks in advance.
Catherine X Wang
2004 Apr 22
1
Lyapunov exponent?
Hello,
Does anybody know if there is somewhere in R a function to calculate the
Lyapunov exponent in a time series?
Thanks,
Philippe Grosjean
.......................................................<??}))><....
) ) ) ) )
( ( ( ( ( Prof. Philippe Grosjean
\ ___ )
\/ECO\ ( Numerical Ecology of Aquatic Systems
/\___/ ) Mons-Hainaut University, Pentagone
/ ___ /( 8, Av. du
2008 Oct 20
2
R Newbie Question
Hello list,
I just started R today and tried something quite simple. I wanted to
create a colored plot and eventually after hours of fiddling around got
it working. However, my solution seems very suboptimal and I'd really
appreciate your hints on how to improve. I believe that R already offers
many functions I coded (e.g. distance between two vectors, vector
length, vector normalization and
2001 Feb 27
2
rsa_public_encrypt() exponent too small or not odd
I am attempting to deploy OpenSSH.
The trouble is I keep getting the rsa_public_encrypt() exponent too small or
not odd with the SSH 1 or 1.5 protocols. I can't get OpenSSH to communicate
with itself with any protocal other than SSH 2.
Platform notes:
HP-UX 11.00 Dart 51 64bit
OpenSSL 0.9.6
Zlib 1.1.3
Cflags:
-Ae
I have tried with and without optimizations. I noticed that this problem
2011 Jul 13
1
exponent function help??
I'm trying to make a function that will output the exponent... so f2(2,2) = 4
and f2(2,3)=8. But I don't want to just use the x^n function, I want to do
it another way, and without a recursion. I did the follow code but for some
reason it doesn't work. Help please?
f2 <- function(x, n) #without recursion {
y <- 1
if (n==0) {return(1)} else {
if (length(y) < (n+1) {
y
2009 Mar 17
1
R freeze when loading dll with dyn.load
Good morning,
I am investigating dll import in R under Windows XP. Using examples I found on the internet, I started with a very simple dll, e.g. including only the basic function:
void
{
*x2 = x*x;
}sqr(doublex, double*x2)
I compiled it as a dll with Eclipse and Cygwin's gcc. It works when I call it with another simple .exe C program, compile with Eclipse and gcc as well. I can do what I
2016 May 19
2
External function resolution: MCJIT vs ORC JIT
Thanks so much! This seems to do the trick. I would have spun my wheels for a long time before discovering all of this, wow.
Do I even want to know what additional chickens need to be sacrificed to get this to work on Windows?
-- lg
> On May 18, 2016, at 1:52 PM, Lang Hames <lhames at gmail.com> wrote:
>
> Hi Larry,
>
> You're basically there, but you're hitting
2016 May 17
3
External function resolution: MCJIT vs ORC JIT
When using ORC JIT, I'm having trouble with external function resolution (that is, of a function defined in the app, with C linkage).
I add a declaration for the function to my IR, and when I use MCJIT, it finds it and all is well, But when I use ORC JIT (I *think* correctly, at least it closely matches what I see in the tutorial), I get an LLVM error, "Program used external function
2016 May 20
0
External function resolution: MCJIT vs ORC JIT
Hi Larry,
Thanks so much! This seems to do the trick. I would have spun my wheels for
> a long time before discovering all of this, wow.
No worries. :)
I'll try to keep this in mind and make sure I address it in future
Kaleidoscope tutorial chapters - these issues tripped me up the first time
I encountered them too.
Do I even want to know what additional chickens need to be sacrificed
2016 May 22
1
External function resolution: MCJIT vs ORC JIT
>> llvm::sys::DynamicLibrary::LoadLibraryPermanently(nullptr)
This is one is a bit tricky and hard to find.
I spent quiet some time digging into MC and ORC JIT execution engines trying to find what makes them work.
The problem is that this trick (LoadLibraryPermanently) happens inside of EngineBuilder, despite that the functionality belongs to a JIT engine itself, not to the builder.
I
2003 Dec 04
1
R code for estimating Hurst exponent
Has anyone writen R code for estimating Hurst exponent with R/S method
or other methods?
or any other source of R code available?
Many thanks
Catherine Wang
2002 Apr 03
1
optim()
I was having some problems persuading optim() to give me the answers I
wanted,
& simplified down to:
sqr<-function(x){(x+1)^2}
optim(1,sqr)
I accept this is a hammer to crack a nut, but was still expecting the
answer -1.
I got:
$par
[1] -0.8
$value
[1] 0.04
$counts
function gradient
12 NA
$convergence
[1] 0
$message
NULL
so I've
2012 Apr 25
1
Help on time series & Hurst exponent
Hello,
I'm an absolute beginner with R. I'm hoping to do some time-series analysis
on my data. The data looks like
#time value
18 153
20 426
70 7
83 130
84 7
and so on where time could be in seconds or hours or days (not all at the
same time). How could I import such a file to R and do some simple stuff
(say plot the values)? As per the tutorials on time series, I could use the
ts()
2009 Feb 26
2
[LLVMdev] Impressive performance result for LLVM: complex arithmetic
Following a discussion about numerical performance on comp.lang.functional
recently I just tried running a simple C mandelbrot benchmark that uses C99's
complex arithmetic using gcc and llvm-gcc on a 2.1GHz Opteron 2352 running
Debian:
gcc: 5.727s
llvm-gcc: 1.393s
There is still 20% room for improvement but LLVM is >4x faster than gcc here.
Sweet.
Here's the code:
#include