[petsc-users] Does the ciss solver ignore deflation space?

[Giacomo Mulas]

Hello, I am trying to experiment with the ciss solver to see if it can be
more efficient for my calculation. I need to compute the eigenpairs of a
sparse real symmetric matrix. I don't know in advance how many I will need
to compute, the convergence condition is on the subspace of converged
eigenvectors. I don't know in advance the range(s) in which "good"
eigensolutions (for my problem) will be.
So my approach with other solvers has been to compute some
eigensolutions for each call to epssolve, each time setting a deflation
space with previously found eigenvectors. Not superefficient but it works,
and it scales.
However, when I attempt this with the ciss solver I keep getting the same
eigenpairs over and over, regardless of the deflation space. Any clue as to
why this happens and/or how to cure this?

Thanks in advance, best regards
Giacomo

-- 
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Giacomo Mulas <gmulas at oa-cagliari.inaf.it>
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INAF - Osservatorio Astronomico di Cagliari
via della scienza 5 - 09047 Selargius (CA)

tel.   +39 070 71180244
mob. : +39 329  6603810
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"When the storms are raging around you, stay right where you are"
                          (Freddy Mercury)
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