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Re: error "can't perform indexing operations for <unknown type> type"
From: |
David Bateman |
Subject: |
Re: error "can't perform indexing operations for <unknown type> type" |
Date: |
Sat, 15 Oct 2005 21:32:24 +0200 |
User-agent: |
Mozilla Thunderbird 1.0.2 (Windows/20050317) |
cmire a écrit :
I'm new to Octave, and I've got a short Matlab program from a professor that
we are supposed to modify to solve some homework problems. I've read that
Octave can run Matlab code (I've updated the ~/octaverc file accordingly,
etc.).
When I try to run the code using the command "source(Exercise.m)", I get the
output:
length = 10
npoints = 200
mass = 0.070000
num_sol = 4
error: can't perform indexing operations for <unknown type> type
error: evaluating argument list element number 1
I don't need help with the actual homework assignment -- I just need to get
this code working so I can proceed to do my homework. Help is greatly
appreciated!
Not sure why there is this error, and is certainly a bug in the version
of octave you are using as it indicates that an uninitalized value is
being returned from a compiled function, might be due to issues with eigs..
In any case the only version of eigs that exists for octave is the one I
have that has serious stability problems and only works (and then just)
for real symmetric marices. So I haven't made this version of eigs
available. You therefore have two choices. 1) Forget trying to use
octave for this code, or
2) change the eigs call to read something like
[phi,te] = eig(Hmatrix);
[te, idx] = sort(Hmatrix);
te = te(1:num_sol);
phi = phi(:,idx(1:num_sol));
though for large matrices and small num_sol this will be significantly
slower than using eigs as all of he eigenvectors are calculated and you
only pick num_sol of them.
D.
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