Displaying 20 results from an estimated 752 matches for "convoluting".
2011 Feb 26
1
2D Convolution Function
Dear R-Helpers,
I want to try the 2D (two-dimensional) convolution in R.
For example, let us we have the following kernel and data.
kernel <- (1,2,3,2,1)
data <- array(1:100, dim=c(10,10))
I know the function 'convolve' only for one-dimensional convolution, but it
is just for a 1D sequence.
Is there any function for 2D convolution?
For theory, please refer to the following link:
2010 Jun 04
2
Convolution vector to be derived
I want to generate the following outcome using convolution of two sequences.
x <- c(1,2,3,4,5)
y <- c(6,7,8,9)
The resulting convolution vector is
6
19
40
70
100
94
76
45
When using convolve(), it is hard to produce the result above.
Would you help me out to get that?
Best regards
Moohwan Kim
2011 May 18
1
Convolution confusion:
Hi,
I'm new to R, and I'm a bit confused with the "convolve()" function.
If I do:
x<-c(1, 2, 3)
convolve(x, rev(x), TRUE, "open")
= 9 12 10 4 1
But I expected: 3 8 14 8 3 (like in Octave/MATLAB - conv(x, reverse(x)) )
3 2 1 x 1 2 3
= 3 2 1
0 6 4 2
0 0 9 6 3
= 3 8 14 8 3
The thing is, that "convolve(x, x, TRUE, "open")" works.
For me
2007 Feb 06
0
convolve: request for "usual" behaviour + some improvements + some fixes
To add to the wish-list for "convolve":
For modeling processes that decay exponentially in time, e.g.,
fluorescence, it is desirable to have a function that convolves an
arbitrary vector with an exponential using an iterative method.
In the TIMP package (which won't be on CRAN till R 2.5.0 is official, but
is for now at www.nat.vu.nl/~kate/TIMP) we implemented this
special-purpose
2005 Feb 15
1
convolution of functions
Dear sir,
we would like to know if there exist any R package containing the
computational performance of the n-fold Stieljes' convolution of functions.
We look forward to hearing from you.
Thank you in advance.
____________________________________
M.Luz G?miz P?rez
Dpt. Estad?stica e Investigaci?n Operativa
Facultad de Ciencias
Universidad de Granada
Telf.: 958-243156
e-mail:
2000 Jan 28
0
convolution bug (PR#408)
Full_Name: Bill Simpson
Version: 65.1 , 0.90.1
OS: Linux
Submission from: (NULL) (193.62.250.209)
I reported this on r-help, but here is official bug report.
The present convolve() does not do convolution by default. Its default behaviour
is
correlation. This is a bug.
The default argument conj should be set to FALSE.
The zero-padding should be on the right for linear convolution (don't
1999 Nov 18
1
convolve bug?
I have been experimenting with convolve().
What I know about convolution I learned from engineering (they call this
stuff linear systems theory), not statistics, so maybe this is all just a
matter of different conventions. BUT I notice very weird things with
convolve().
1. First example, from the classic Bracewell The Fourier transform and its
applications, chap 3 (p.32 in 2nd edition):
{2 2 3 3
2005 Sep 29
2
solution of convolution equation
Hello,
May be somebody can help me...
I am trying to find a solution of a convolution equation using fft (and
unfortunately I do not have a good background for this).
So I am just trying to figure out how it can be implemented in R. I have
two multidimensional independent variables X and Z
and I know their densities fx and fz, which are multidimensional arrays.
So I have to find the density of
2005 Dec 23
2
convolution of the double exponential distribution
Is there any R function that computes the convolution of the double
exponential distribution?
If not, is there a good way to integrate ((q+x)^n)*exp(-2x) over x from
0 to Inf for any value of q and for any positive integer n? I need to
perform the integration within a function with q and n as arguments. The
function integrate() is giving me this message:
"evaluation of function gave a
2001 Jun 04
1
2D convolution
Dear all,
I have an image that I need to filter, and so I'm looking for a method to
convolve it with a matrix. If I understood the docs for convolve
correctly, it only works in 1D (and I have tried to convolve, it didn't
look good).
So, I wondered if anybody have implemented 2D convolution in R, or have
any good advices to share (beyond having a look at mvfft), before I go
hacking?
2005 Jul 20
2
Issues with convolve
We obtained some disturbing results from convolve() (inaccuracies and negative
probabilities). We'll try to make the context clear in as few lines as
possible...
Our function panjer() (code below) basically computes recursively the
probability mass function of a compound Poisson distribution. When the
Poisson parameter lambda is very large, the starting value of the recursive
scheme ---
2005 Jun 15
1
Chi square convolution?
Hi,
I want to determine the confidence interval on the sum of two sigma's.
Is there an easy way to do this in R? I guess I have to use some sort of
chisquare convolution algorithm???
Thanx,
Roy
--
The information contained in this communication and any atta...{{dropped}}
2018 Feb 09
0
Convolutional neural networks (CNN) - build a model and After?
Hi,
I am learning CNN using MXNet R package. I am following this great tutorial
about olivetti_faces reconnaissance
<https://www.r-bloggers.com/image-recognition-tutorial-in-r-using-deep-convolutional-neural-networks-mxnet-package/>.
In the end after building model and testing the final score was 0.975.
It is great score but what can do after with this model?
How can use this model for
2011 Feb 04
2
Avoiding two loops
Hello,
I have a R code for doing convolution of two functions:
convolveSlow <- function(x, y) {
nx <- length(x); ny <- length(y)
xy <- numeric(nx + ny - 1)
for(i in seq(length = nx)) {
xi <- x[[i]]
for(j in seq(length = ny)) {
ij <- i+j-1
xy[[ij]] <- xy[[ij]] + xi * y[[j]]
}
}
xy
}
How do I reduce the 2
2005 Feb 23
1
WinXP not caching credentials
I have three Windows XP (All SP2) machines that won't cache credentials
with a Samba DC.
A Debian Sarge system with Samba 3.0.10 is the domain controller. It has
three users and three machine accounts.
The three users all are simple Unix users, with no mapping to Windows
users.
We use DHCP (entirely different server) and DNS, but local IPs do not
resolve.
The configuration files for Samba
2007 Feb 02
1
Inaccuracy in ?convolve
Hi,
Man page for 'convolve' says:
conj: logical; if 'TRUE', take the complex _conjugate_ before
back-transforming (default, and used for usual convolution).
The complex conjugate of 'x', of 'y', of both?
In fact it seems that it takes the complex conjugate of 'y' only which
is OK but might be worth mentioning because (1) conj=TRUE is the
2006 May 12
6
Newbie to R: would like to solve a problem
Hello, I am very new to R (read the introduction a few hours ago), but
experianced in several other languages (including Scheme, C, ObjC and
C++, Java and Javascript) and I was wondering how to approach this
problem:
I am making a training calculator for a Video Game I play. Basically,
I want to calculate the probability of killing an enemy within x hits,
to help determine which is the best
2016 Jun 03
2
Custom assembler subset
On Fri, Jun 3, 2016 at 11:53 AM, Ahmed Bougacha <ahmed.bougacha at gmail.com>
wrote:
> -llvmdev at cs.uiuc.edu, that list isn't in use anymore.
>
> On Wed, Jun 1, 2016 at 4:48 PM, Kenneth Adam Miller via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> > Hello all,
> >
> > I would like to restrain the compiler that I build on my local box from
>
2024 Jan 23
0
Quantiles of sums of independent discrete random variables
Greetings,
I have the following?
Problem:
Given k (=10) discrete independent random variables X_i with n_i (= 5 to 20) values each,compute quantiles of the distribution of the sum X = X_1+...+X_k.
Here X has n=n_1 x n_2 ... n_k distinct values which is too large to list them all together with
their probabilities.
I tried several approaches:
(A) Convolution:
each X_j is approximated with
2005 Aug 27
2
Defining an ex-gaussian PDF
How does one define PDFs as yet undefined in R, such as the ex-
gaussian, the sum of two RVs, one exponential, one Gaussian? The PDF
would then be the convolution of an exponential PDF, dexp(), and a
normal, dnorm().
Kindly cc me in your reply to r-help.
Thanks,
_____________________________
Professor Michael Kubovy
University of Virginia
Department of Psychology
USPS: P.O.Box 400400