Displaying 20 results from an estimated 200 matches similar to: "riwish() problem"
2012 Mar 01
1
Parameterization of Inverse Wishart distribution available in MCMCpack and bayesm libraries
Hello Everyone
Both the MCMCpack and the bayesm libraries allow us to make draws from the
Inverse Wishart distribution.
But I wanted to find out how exactly is the Inverse Wishart distribution
parameterized in these libraries.
The reason I ask is the following:
Now its generally standard to express Inverse Wishart as IW(0.5 * DOF,0.5*
Scale). (DOF-> Degree of freedom, Scale -> Scale
2007 Jul 24
1
function optimization: reducing the computing time
Dear useRs,
I have written a function that implements a Bayesian method to
compare a patient's score on two tasks with that of a small control
group, as described in Crawford, J. and Garthwaite, P. (2007).
Comparison of a single case to a control or normative sample in
neuropsychology: Development of a bayesian approach. Cognitive
Neuropsychology, 24(4):343?372.
The function (see
2011 May 21
7
[cryptography] rolling hashes, EDC/ECC vs MAC/MIC, etc.
----- Forwarded message from Zooko O''Whielacronx <zooko at zooko.com> -----
From: Zooko O''Whielacronx <zooko at zooko.com>
Date: Sat, 21 May 2011 12:50:19 -0600
To: Crypto discussion list <cryptography at randombit.net>
Subject: Re: [cryptography] rolling hashes, EDC/ECC vs MAC/MIC, etc.
Reply-To: Crypto discussion list <cryptography at randombit.net>
2012 Feb 05
1
Simulating from a Normal Inverted Wishart distribution
Hello everyone
I was wondering how would one simulate from a Normal Wishart Distribution
in R.
A normal inverted Wishart distribution is denoted by NIW (M,C,d,S), where
X/(Sigma) ~ N( M,C,(Sigma) ) -> a matrix normal distribution, (Sigma) ->
column dispersion matrix
(Sigma) ~ IW (d,S) -> inverted Wishart distribution
Thanks a lot !
Best
Shantanu
[[alternative HTML version
2003 Mar 31
2
Does R have an inverse wishart distribution?
If so, I''ve had trouble finding it. Can anyone help?
2005 Jul 26
1
Wishart Density
Dear R users,
I am doing MCMC using Metropolis-Hastings. My model is
bivariate-log-normal and the prior for variance-covariance is wishart
distribution. I am wondering if there are some simple codes about how
to get the density of Wishart distribution in my case ?
Thanks in advance.
Meihua
[[alternative HTML version deleted]]
2023 Feb 28
1
Checksums and other verification
On Tue, Feb 28, 2023 at 12:24:04PM +0100, Laszlo Ersek wrote:
> On 2/27/23 17:44, Richard W.M. Jones wrote:
> > On Mon, Feb 27, 2023 at 08:42:23AM -0600, Eric Blake wrote:
> >> Or intentionally choose a hash that can be computed out-of-order, such
> >> as a Merkle Tree. But we'd need a standard setup for all parties to
> >> agree on how the hash is to be
2010 Sep 06
1
sample a matrix with one element to be 1 from wishart distribution
Hi,
I am not sure if this make sense at all. I'd like to sample a matrix, which
follows a wishart / inverted wishart distribution. However, the (1,1)
element of this matrix should always be equal to 1. How can I handle it in
R? Any suggestion is greatly appreciated. Thanks a lot.
Sonia
[[alternative HTML version deleted]]
2009 Nov 21
3
python
Dear R users,
I would like to make my R code for MCMC faster. It is possible to integrate
C code into R but I think C is too complicated for me. I would need a C
introduction only for MCMC and I do not know if such a thing exists.
I was thinking of Python (and scipy). Where could I read about its
integration into R ? How developed are the statistical packages in Python ?
I could not find a
2023 Feb 27
2
Checksums and other verification
https://github.com/kubevirt/containerized-data-importer/issues/1520
Hi Eric,
We had a question from the Kubevirt team related to the above issue.
The question is roughly if it's possible to calculate the checksum of
an image as an nbdkit filter and/or in the qemu block layer.
Supplemental #1: could qemu-img convert calculate a checksum as it goes
along?
Supplemental #2: could we detect
2003 Feb 16
1
multivariate sampling question again
Hi
Thanks for replying my question! What really interested me is that the
package providing some complex form sampling, such as wishart,
multinomial, dirichlet. And others for example conditional beta
distribution confining the random variable in the interval (a, b). Since
these concept are widely used in the baysian, I wonder whether somebody
has already written this package. Thanks!
Best
2009 Oct 30
30
Truncating SHA2 hashes vs shortening a MAC for ZFS Crypto
For the encryption functionality in the ZFS filesystem we use AES in CCM
or GCM mode at the block level to provide confidentiality and
authentication. There is also a SHA256 checksum per block (of the
ciphertext) that forms a Merkle tree of all the blocks in the pool.
Note that I have to store the full IV in the block. A block here is a
ZFS block which is any power of two from 512 bytes to
2005 Aug 03
1
multivariate F distribution
Dear List,
Is there any function in R to generate multivariate F distribution with
given correlation/covariance matrix?
Actually, I just want to generate some 2-dimentional non-normal data
sets (skewed) for low (may be around 0.3 cor coeff.) negatively and also
positively correlated variables ?
Thanks in advance.
Anna
2011 Aug 12
1
sapply to bind columns, with repeat?
Hi R-help,
I am working with US COOP network station data and the files are
concatenated in single rows for all years, but I need to pull these
apart into rows for each day. To do this, I need to extract part of
each row such as station id, year, mo, and repeat this against other
variables in the row (days). My problem is that there are repeated
values for each day, and the files are fixed width
2017 Feb 09
2
Checksums for git repo content?
On 02/09/2017 01:11 PM, Leonard den Ottolander wrote:
> On Thu, 2017-02-09 at 12:58 -0600, Johnny Hughes wrote:
>> At the time of extraction, the <name>.metadata file is created (again,
>> not by us, but by the Red Hat team that distributes source), and all the
>> non-text sha1sums are in there as well as all the text sources.
>
> Aha, <name>.metadata, well,
2023 Feb 27
1
Checksums and other verification
On Mon, Feb 27, 2023 at 08:42:23AM -0600, Eric Blake wrote:
> Or intentionally choose a hash that can be computed out-of-order, such
> as a Merkle Tree. But we'd need a standard setup for all parties to
> agree on how the hash is to be computed and checked, if it is going to
> be anything more than just a linear hash of the entire guest-visible
> contents.
Unfortunately I
2008 Sep 26
1
Generating a valid covariance matrix
I want to generate a valid variance-covariance matrix. One way could be to generate some random sample from multivariate normal distribution and then calculate cov. matrix. Another way could be to sample from wishart distribution itself. However both cases need a valid i.e. PD covariance matrix. As I need to generate that covariance matrix only, I am not interested those two methods. Can anyone
2012 Dec 19
1
Theoretical confidence regions for any non-symmetric bivariate statistical distributions
Respected R Users,
I looking for help with generating theoretical confidence regions for any
of non-symmetric bivariate statistical distributions (bivariate Chi-squared
distribution<Wishart distribution>, bivariate F-distribution, or any of the
others). I want to to used it as a benchmark to compare a few strategies
constructing confidence regions for non-symmetric bivariate data.
There is
2006 Feb 20
1
Plots: displaying mathematical symbols in specific fonts
Dear SavioRs,
I am doing some research where characters in different microsoft
fonts serve as experimental stimuli. Hence, in plot labels, I would
like to display the characters in specific microsoft fonts. I have
figured out how to display letters and numbers, but I am having
trouble with symbols such as capital delta. Before I go further, I
am using R 2.2.1 on Windows XP with everything
2023 Feb 28
1
Checksums and other verification
On 2/27/23 17:44, Richard W.M. Jones wrote:
> On Mon, Feb 27, 2023 at 08:42:23AM -0600, Eric Blake wrote:
>> Or intentionally choose a hash that can be computed out-of-order, such
>> as a Merkle Tree. But we'd need a standard setup for all parties to
>> agree on how the hash is to be computed and checked, if it is going to
>> be anything more than just a linear hash