On 9/27/22 21:02, 'yy.wayne' via deal.II User Group wrote:
Just one last question. So if I have the same problem coded in real+imaginary
or complex and solve with SparseDirect solver or Krylov subspace methods. Will
there be difference in time consumption (due to larger matirx / or harder to
solve complex arithmetic embedded in those solver)?
For Krylov subspace methods, everything depends on the preconditioner and it
is not possible to make general predictions without knowing what you want to
use for the preconditioner.
For SparseDirectUMFPACK, I suspect that using complex arithmetic is faster
than using separate real/imaginary components. By how much is something I have
never measured -- you probably need to measure this yourself. It would not
greatly surprise me if it was faster by a factor of 4 or 6, but I don't think
it should be a factor of 20 for example.
Best
Wolfgang
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Wolfgang Bangerth email: [email protected]
www: http://www.math.colostate.edu/~bangerth/
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