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Line 305... |
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Use PETSC_DECIDE for ncv and mpd to assign a reasonably good value, which is
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Use PETSC_DECIDE for ncv and mpd to assign a reasonably good value, which is
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dependent on the solution method.
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dependent on the solution method.
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The parameters ncv and mpd are intimately related, so that the user is advised
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The parameters ncv and mpd are intimately related, so that the user is advised
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to set one of them at most. Normal usage is the following:
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to set one of them at most. Normal usage is that
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(a) In cases where nev is small, the user sets ncv (a reasonable default is 2*nev).
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(a) in cases where nev is small, the user sets ncv (a reasonable default is 2*nev); and
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(b) In cases where nev is large, the user sets mpd.
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(b) in cases where nev is large, the user sets mpd.
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The value of ncv should always be between nev and (nev+mpd), typically
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The value of ncv should always be between nev and (nev+mpd), typically
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ncv=nev+mpd. If nev is not too large, mpd=nev is a reasonable choice, otherwise
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ncv=nev+mpd. If nev is not too large, mpd=nev is a reasonable choice, otherwise
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a smaller value should be used.
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a smaller value should be used.
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Line 466... |
the algorithm that computes both right and left eigenvectors. This is
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the algorithm that computes both right and left eigenvectors. This is
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usually much more costly. This option is not available in all solvers.
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usually much more costly. This option is not available in all solvers.
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Level: intermediate
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Level: intermediate
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.seealso: QEPGetLeftVectorsWanted(), QEPGetEigenvectorLeft()
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.seealso: QEPGetLeftVectorsWanted()
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@*/
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@*/
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PetscErrorCode QEPSetLeftVectorsWanted(QEP qep,PetscBool leftvecs)
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PetscErrorCode QEPSetLeftVectorsWanted(QEP qep,PetscBool leftvecs)
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{
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{
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PetscFunctionBegin;
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PetscFunctionBegin;
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PetscValidHeaderSpecific(qep,QEP_CLASSID,1);
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PetscValidHeaderSpecific(qep,QEP_CLASSID,1);
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