Martin Maechler <[EMAIL PROTECTED]> writes:
> The update is actually available online
> from http://epubs.siam.org/sam-bin/dbq/article/41801
> with the extended title ", 25 Years Later" .
To some, that is. I can download it to the work machine, but if I do
it from home, all I get is a
...
Prompted by this thread, I have tidied up a Fortran program I wrote
with Marina Shapira. We would be happy for this ("mexp") to become
part of R, either as a contributed package or as part of the base
distribution if it's good enough. I have packaged it and put it at
http://www.warwick.ac.uk
> "PD" == Peter Dalgaard <[EMAIL PROTECTED]>
> on 21 Jan 2004 19:08:38 +0100 writes:
PD> Martyn Plummer <[EMAIL PROTECTED]> writes:
>> Calculating the matrix exponential is harder than it
>> looks (I'm sure Peter knows this). In fact there is a
>> classic paper by Moler
Dear All,
Thanks for all the help. I tried to implement Stephane Dray's suggestion
and Erin Hodgess function with the following matrices:
> A
[,1] [,2]
[1,]21
[2,]13
> P
[,1] [,2] [,3]
[1,]123
[2,]456
[3,]234
> D
[,1] [,2] [,3]
[1
Martyn Plummer <[EMAIL PROTECTED]> writes:
> Calculating the matrix exponential is harder than it looks (I'm sure
> Peter knows this). In fact there is a classic paper by Moler and Van
> Loan from the 1970s called "Nineteen dubious ways to calculate the
> exponential of a matrix", which they updat
On Tue, 2004-01-20 at 16:58, Peter Dalgaard wrote:
> Federico Calboli <[EMAIL PROTECTED]> writes:
>
> > Dear All,
> >
> > I would like to ask why the zeroeth power of a matrix gives me a matrix
> > of ones rather than the identity matrix:
>
> Because arithmetic on a matrix works element-wise. M
On 20 Jan 2004 16:40:07 +, Federico Calboli <[EMAIL PROTECTED]>
wrote :
>Dear All,
>
>I would like to ask why the zeroeth power of a matrix gives me a matrix
>of ones rather than the identity matrix:
R doesn't have a power operator that knows it's working on a matrix.
M^x raises each entry o
Dear Federico,
The common arithmetic operators such as ^ operate on the elements of
matrices (or vectors or arrays). Similarly, * gives the element-wise
product and not the matrix product.
I hope that this helps,
John
At 04:40 PM 1/20/2004 +, Federico Calboli wrote:
Dear All,
I would like
> -Original Message-
> From: Federico Calboli
> Sent: Tuesday, January 20, 2004 5:40 PM
> To: r-help
> Subject: [R] matrix exponential: M^0
>
> I would like to ask why the zeroeth power of a matrix gives me a matrix
> of ones rather than the identity matrix:
>
> > D<-rbind(c(0,0
Hello,
be careful D^0 is not the zeroeth power of a matrix. It is a term power
:D[i,j]^0=1
To obtain the power of a matrix, you can use a decomposition such as svd:
X = U D V'
the n-th power of X is X = U D^n V'
svd1=svd(D)
Apower0=svd1$u%*%diag(svd1$d^0)%*%t(svd1$v)
At 11:40 20/01/2004, Federic
Federico Calboli <[EMAIL PROTECTED]> writes:
> Dear All,
>
> I would like to ask why the zeroeth power of a matrix gives me a matrix
> of ones rather than the identity matrix:
Because arithmetic on a matrix works element-wise. M^2 is not equal to
M %*% M either (but is equal to M*M).
(R doesn
Federico Calboli wrote:
Dear All,
I would like to ask why the zeroeth power of a matrix gives me a matrix
of ones rather than the identity matrix:
Because ^0 gives you the zero-th power of the _elements_ of the
matrix, not the matrix itself. A matrix of 0^0 is all 1s.
Similary, '*' multiplies
elementary operations, like taking a power, act elementwise on vectors
and matrices. You may use a spectral decomposition to compute powers
of a matrix - or a for loop if you are interested in small integer
powers.
HTH
Giovanni
--
__
[
On Tue, 20 Jan 2004, Federico Calboli wrote:
> Dear All,
>
> I would like to ask why the zeroeth power of a matrix gives me a matrix
> of ones rather than the identity matrix:
Because ^ is not the matrix power. It's the elementwise power.
-thomas
> > D<-rbind(c(0,0,0),c(0,0,0),c(0,0,0)
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