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mpower
From: |
John W. Eaton |
Subject: |
mpower |
Date: |
Wed, 27 Sep 2006 22:38:52 -0400 |
On 27-Sep-2006, Eric and Diana Luft wrote:
| Is there any Octave equivalent to the matlab "mpower" command, which would
compute a matrix to an arbitrary, eg fractional, power? I want to compute a
matrix to the 2/3 power, but I get a complex-valued matrix as a result, where
it should be real-valued. Details follow below, where A2 comes out to be
complex-valued when I think it should be real-valued:
|
| M=[1 1 1; 1 2 2; 1 2 3]
|
| K=[2 -1 .5;-1 1.2 .4;.5 .4 1.8]
|
| A2=logm(inv(M)*K)^(2/3)
Why do you think it should be real valued? What are you trying to
compute, the matrix to a fracional power, or the elements to a
fractional power? When you write the above expression, are you
expecting the matrix (or elements) to be squared first, followed by a
cube-root function? That is not what you have written.
| Thanks for any help or advice,
Searching for mpower here:
http://www.mathworks.com/access/helpdesk/help/techdoc/matlab.html
says that mpower is not a Matlab function. So where did you find
mpower? Is it part of some external toolbox? If so, which one?
Where is the documentation for it?
jwe
- mpower, Eric and Diana Luft, 2006/09/27