**Matrix Exponential**Does IDL have, or has anyone written, a matrix exponential function
similar to the matlab expm()
http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/ref/expm.html
On Thu, 5 Nov 2009 12:20:47 -0800 (PST), Dave L <dave.lenar@gmail.com>
wrote:
>Does IDL have, or has anyone written, a matrix exponential function
>similar to the matlab expm()
> http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/ref/expm.html
It seems you can do this by calculating eigenvectors and eigenvalues.
Look in the help ...

**Request Fortran code for Matrix exponential for a real matrix, with accuracy estimate**Hello,
I was looking for an open source Fortran code to compute Matrix
exponential for a real matrix, with accuracy estimate, something like
http://www.slicot.org/shared/doc/MB05OD.html. I tried to search Scilab
but was not successful.
Thanks for any hint.
Zhu
On 11/12/2011 2:41 PM, Zhu Wang wrote:
> Hello,
>
> I was looking for an open source Fortran code to compute Matrix
> exponential for a real matrix, with accuracy estimate, something like
> http://www.slicot.org/shared/doc/MB05OD.html. I tried to search Scilab
> but was not successful.
>
> Thanks for any hint....

**Exponential Matrix integration**Let B be a nonsingular nxn matrix. I want to integrate the function:
f(t) from 0 to T, where f(t)=exp(Bt)*exp(Bt)'. Can somebody help me?
Thanks.
is t symbolic, or numerical?
numnerical integration?
Cheers...
In article <jlhee8z4ftbh@legacy>,
juliocacho@hotmail.com (Julio) writes:
>Let B be a nonsingular nxn matrix. I want to integrate the function:
>f(t) from 0 to T, where f(t)=exp(Bt)*exp(Bt)'. Can somebody help me?
>Thanks.
>
If B is diagonalizable then
B=T*\Lambda*inv(T) with \Lambda the diagonal matrix of the eigenvalues
and
exp(Bt) = T*d...

**MATRIX LOGARITHM (and EXPONENTIAL)**Just a quick question. Does IDL have a similar command to the popular
MATLAB logm and expm so that I can take the matrix logarithm (and
exponential)? I understand that ALOG and EXP will not function in this
sense.
Thank you,
teddy
On Jan 27, 7:41=A0pm, teddyallen <teddyal...@yahoo.com> wrote:
> Just a quick question. Does IDL have a similar command to the popular
> MATLAB logm and expm so that I can take the matrix logarithm (and
> exponential)? I understand that ALOG and EXP will not function in this
> sense.
Can you explain what matrix log and exp are?
On Ja...

**Fast Matrix Exponential**Hi All,
I was wondering if anyone out there knows a fast alternative to the matrix exponential function expm. Perhaps there is a mex file out there somewhere? The matrix I am considering does not have any special form, except that all its entries are real numbers. I have considered the expokit package, but was wondering if there is anything faster out there.
Thank you very much,
--Raul Gonzalez
"Raul " <ragonzal@alum.mit.edu> wrote in message <hrmaop$at$1@fred.mathworks.com>...
> Hi All,
>
> I was wondering if anyone out there knows a fast alternat...

**Symbolic matrix exponentiation**Hello,
I am attempting to calculate the general form of an equation using symbolic math in the example below. This example, as shown, runs quickly and the result has already been very useful to me.
I am hoping to extend this example to the generalized case. If I allow one more parameter to be free, for example by removing a = 1, then calculating the expm never finishes. The problem goes from being solved in a few seconds to not completing within days.
Ideally I would like to allow all parameters to be free, including a, c, d, and f. Is there a trick that will make this exponentiat...

**Matrix exponentiation in FORTRAN**Hi,
I hope I've come to the right place - please redirect me if there's a
more appropriate forum to be asking these questions.
I am trying to figure out how to compute the exponential of a matrix
in FORTRAN - something similar to expm used in MATLAB, and MatrixExp
in Mathematica. I've gone through LAPACK's online documentation but
couldn't find an answer. Is there some way of getting this done? I'd
appreciate your kind help with this.
Maayan.
Hi,
As if by magic, Maayan appeared !
> Hi,
>
> I hope I've come to the right place - please redirect me if...

**exponential of matrix in fortran90**hi,
I'm looking for a subroutine for fortran90 that could compute
exponential of a matrix?
Is there any subroutine?
I read "Nineteen Dubious Ways to Compute the Exponential of a
Matrix",but I don't know which way is better?
could you help me?
thanks,
Elaheh
In article <d8a80ca7-eb2d-4d5c-9c8f-70964ede639d@h11g2000yqb.googlegroups.com>,
<elaheh.adibi@gmail.com> wrote:
>hi,
>I'm looking for a subroutine for fortran90 that could compute
>exponential of a matrix?
>Is there any subroutine?
>I read "Nineteen Dubious Ways to Compute the Exp...

**Matrix Exponential in Labview**Anybody know how to compute a 'Matrix Exponential' in labview? Either
in the base package or an add-on toolkit. For a an explanation of the
matrix exponential, see:
http://zone.ni.com/devzone/conceptd.nsf/webmain/0CF7E24984DA7D9586256D720054FC07?opendocument
Which the only reference I can find on the web site.
Thanks, Ian Wall
I quickly looked at the document and I do not think you compute the
matrix exponential.
It appears to be an identity. It just says that a matrix to some
power can be expressed as an infinite sum. You can use the two
interchangably in your calculations. For ...

**matrix exponential expm**Hello.
I'm using expm function to solve differential systems of equations for some simulations. It worked fine before for an another program. Now I have the problem that the result matrix contains NaN coefficients or huge coefficients. My guess is that the input matrix isn't well scaled (some coefficients are big others close to zero). But what could I do with that? My idea is to change the units of physical parameters but I just wonder if there is some method provided by Matlab to deal with such problem.
Please help If you can.
Alexandru
"alexandru cornogolub" &...

**Exponential of a matrix indexed by a parameter**I have a matrix which is indexed by a parameter, something like:
2-x 3
4 1+x
where x is a vector; so there is one matrix corresponding to each
value of x. I want to take the matrix exponential of this. Is there a
way to do it without using a "for" loop over all the values of x?
Thanks,
Mauro
Mauro <msmscarlatti@googlemail.com> wrote in message <d1f6d508-89a6-4742-83fe-9a68d7ebe393@e5g2000yqn.googlegroups.com>...
> I have a matrix which is indexed by a parameter, something like:
>
> 2-x 3
> 4 1+x
>
> where x is a...

**Matrix Exponential m-file**Hello. I am trying to compare the performance of the matlab matrix
exponential (expm) command to a custom method, but I can't get apples
to apples since expm is a build-in command and runs much faster. Is
their any way to get a m-file for the expm command.
I know I could make one from consulting the literature, but would
really like to make a quick comparison if I can find an
implementation that uses a non-compiled function.
Regards,
Tim
try expmdemo1
---Bob.
"Tim Booher" <timothy.booher@afit.edu> wrote in message
news:ef24d4a.-1@webx.raydaftYaTP...
> Hello. I am ...

**Integrating matrix exponential function**Hi all,
I have H = H0 + H1*cos(2*pi*Freq*t) with Hermitian matrices
H0 and H1 (size between 3 and 160), and I need to integrate
the function expm(-2i*pi*H(t)*t) over one period [0,1/Freq[.
My implementation sums over ~500 knots using the function
below. Although it is the bottleneck in my overall code, I can't
see a way to make it faster or more accurate with fewer knots.
Does anybody have an idea how to speed it up? Is there a possible
algorithmic improvement?
Thanks, sTefan
%--------------------------------------------------------
function U = oneperiod(H0,H1,Freq,nInt...

**Matrix exponential calculated incorrectly**Apparently, matrix exponential is not working fine for a
large number of different matrices. Below is an example:
intA =
0 0.6620 -2.6724 0 0 0
0.0736 0 0 0 0 0
-190.3624 -0.0002 0 0 0 0
-0.0110 0.0992 0 0 0 -0.0111
0.0992 0.0110 0 0 0 0.1000
0 0 1.0000 0 0 0
>> expm(intA)*expm(-intA)
ans =
1.0e+005 *
0.1931 -0.0054 0.0237 0 0 ...

**simple matrix exponentiation question**Hi all,
I'm trying to perform the following operation: I have a n x k matrix A and a n x 1 vector B. I want to raise all the numbers in the first row of A to the B(1)th power, and similarly, all numbers in the kth row of A to the B(k)th power.
I don't want to use loops - the matrices are large, and vectorised code is important since speed is a concern.
It's a pretty simple operation, but I cant find out how to do it - any suggestions?
"patsm Smith" <dom1823@gmail.com> wrote in message <guk6r1$16b$1@fred.mathworks.com>...
> Hi all,
>
> I'm t...

**Matrix exponential calculated incorrectly #3**Apparently, matrix exponential is not working fine for a
large number of different matrices. Below is an example:
intA =
0 0.6620 -2.6724 0 0 0
0.0736 0 0 0 0 0
-190.3624 -0.0002 0 0 0 0
-0.0110 0.0992 0 0 0 -0.0111
0.0992 0.0110 0 0 0 0.1000
0 0 1.0000 0 0 0
>> expm(intA)*expm(-intA)
ans =
1.0e+005 *
0.1931 -0.0054 0.0237 0 0 ...

**finding subarrays of exponentials from a matrix of cells**I have imported the following dataset into MatLab as a cell array (previously included other deleted textual data). To simplify I have listed the much larger here as a matrix as 3 columns of cells containing "numbers" that I would like to write in separate Excel *.xls files using a decimal 6.3 format. The first cell contains an "integer", whereas the other two columns contain cells containing "numbers" in "exponential notation".
I want the data to be sent to separate files depending on the value of the contents in the first column of each row [cell...

**Matrix exponential calculated incorrectly #2**Apparently, matrix exponential is not working fine for a
large number of different matrices. Below is an example:
intA =
0 0.6620 -2.6724 0 0 0
0.0736 0 0 0 0 0
-190.3624 -0.0002 0 0 0 0
-0.0110 0.0992 0 0 0 -0.0111
0.0992 0.0110 0 0 0 0.1000
0 0 1.0000 0 0 0
>> expm(intA)*expm(-intA)
ans =
1.0e+005 *
0.1931 -0.0054 0.0237 0 0 ...

**taking the exponential of only the nonzero elements of a sparse matrix**Dear All,
Matlab help tells me that "Multiplication and division are performed on only the nonzero elements of sparse matrices." What about something similar for the exponential?
Specifically, given a sparse matrix A, I wish to obtain a sparse matrix B, such that
B(i,j)=exp(A(i,j)), for all nonzero A(i,j)
B(i,j)=0, for all zero A(i,j)
I'm only interested in the exponents of the nonzeros, and calculating the exponents of a vast number of zeros slows things down a little bit.
Thank you for your help.
"Akim " <aaa@bbb.ccc> wrote in message <gkmlm5$f7s$1@fred...

**How to build a exponentially weighted moving average covariance matrix?**Hi
I'm desperatly need help with my school project and I hope you guys can help me with this problem. I am new to Matlab and my coding skills are really bad.
I would need a code that would solve this EWMA equation. I also need to solve this many times so I have to put it in a loop so take this in to consideration (if it's needed).
H0=lambda*X*X'+(1-lambda)*H-1
Explaining the equation:
H0=EWMA covariance matrix at time t
lambda=smoothing parameter
X=observation matrix at time t-1
X'=observation matrix transposed at time t-1
H-1=the EWMA covariance matrix for t-...

**Floating point operation count for a complex matrix exponential?**Hi all,
I am attempting to estimate the computational load for an iterative
algorithm. One step requires the following calculation:
B = exp(i*A)
where A is an N x N complex double-precision matrix.
I would like to find the number of floating point operations required
for this procedure. Any pointers to appropriate resources would be very
greatly appreciated!
TIA,
Hal
"@(nospam)rmc.ca" <""harry.ingleby\"@(nospam)rmc.ca"> wrote in message news:42431aa7$1@rmcnt03a.rmc.ca...
> Hi all,
>
> I am attempting to estimate the computational load f...

**matrix in a matrix**hallo there.
I want to put a matrix that is 128X128 in a matrix that is 512X512 ( ones(512) ).
what I want to do is to have the white image and above to put the second image ( a letter, A for example).
I cant multiply cause they dont have the same dimensions.
any ideas??
thanks in advance
"th " <THOMITSU@YAHOO.COM> wrote in message <hsjabs$bbc$1@fred.mathworks.com>...
> hallo there.
>
> I want to put a matrix that is 128X128 in a matrix that is 512X512 ( ones(512) ).
>
> what I want to do is to have the white image and above ...

**Matrix in a matrix?**Hi to all,
I've encountered a problem using Matlab. As I'm not very familiar
with matlab, there are functions which I have not used before.
What I would like to know, if there is a way to express a matrix
within a matrix. For example,
R= [ r1 r2 r3 ... rn]
where rn=[xn yn tn]
and xn, yn, tn are column of numbers.
I used the following code below to express the numbers in rn as
coloumns for easy referencing.
xn=r(:,1); %represents the columns in the matrix
yn=r(:,2);
tn=r(:,3);
My objective is to be able to retrieve information in the matrix
easily and compare their values. Meani...

**matrix in matrix (?)**Hi, I need help!
I want to construct a matrix 10x10 where every element is a matrix
?x2.
After, I need to extract the ?x2 matrix by the 10x10.
how to make that?
mirus wrote:
> Hi, I need help!
>
> I want to construct a matrix 10x10 where every element is a matrix
> ?x2.
>
> After, I need to extract the ?x2 matrix by the 10x10.
>
> how to make that?
have a look at cell arrays. they provide the possibility to store
arbitrary data in an array like fashion.
michael
Michael Wild wrote:
> mirus wrote:
>> Hi, I need help!
>>
>> I want to constru...