Inconsistent EigenVectors on running same problem multiple times
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Hi All,
In my FEM code, I run EIG or EIGS command for getting eigenvalues and eigenvectors. Strangely, it is returning different eigenvectors that are inconsistent each time for the same code and same inputs.
Any help will be appreciated.
Best regards,
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Answers (1)
Walter Roberson
on 9 Jan 2016
If I recall, a few weeks ago someone mentioned that there is a random initialization going on (might have been by at the qr level.) Try setting the random seed, trying, setting it again, see if you get the same results.
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Guillaume
on 11 Jan 2016
No, as has been said, you can fix the seed of RNG to the same number before each time you call eigs, so that the 'random' number it uses is always the same and thus, always returns the same result.
As per Walter's later comment:
rng(12345); %use any seed you want
[A1,B1] = eigs(KM,20,'sm');
rng(12345); %as long as it's always the same
[A2,B2] = eigs(KM,20,'sm');
Steven Lord
on 11 Jan 2016
Or set the v0 option in your EIGS call to fix the starting vector. By default, it is randomly generated.
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