From 3327ba15d3c7d49a5d5201ea2bc3df48ffcd5837 Mon Sep 17 00:00:00 2001 From: kronbichler Date: Tue, 18 Nov 2008 13:26:08 +0000 Subject: [PATCH] Modified a comment in the Chebyshev preconditioner. git-svn-id: https://svn.dealii.org/trunk@17626 0785d39b-7218-0410-832d-ea1e28bc413d --- .../lac/include/lac/trilinos_precondition.h | 28 +++++++++++++++---- 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/deal.II/lac/include/lac/trilinos_precondition.h b/deal.II/lac/include/lac/trilinos_precondition.h index 7ad20e145a..db81826c6a 100755 --- a/deal.II/lac/include/lac/trilinos_precondition.h +++ b/deal.II/lac/include/lac/trilinos_precondition.h @@ -984,7 +984,11 @@ namespace TrilinosWrappers /** * This determines the degree of the - * Chebyshev polynomial. + * Chebyshev polynomial. The degree + * of the polynomial gives the number + * of matrix-vector products to be + * performed for one application of + * the vmult() operation. */ unsigned int degree; @@ -1021,12 +1025,24 @@ namespace TrilinosWrappers double min_diagonal; /** - * This flag let the preconditioner - * start at a nonzero value when - * generating the Chebyshev - * polynomial. + * When this flag is set to + * true, it enables the + * method vmult(dst, src) to + * use non-zero data in the vector + * dst, appending to it the + * Chebyshev corrections. This can be + * useful in some situations + * (e.g. when used for high-frequency + * error smoothing), but not the way + * the solver classes expect a + * preconditioner to work (where one + * ignores the content in + * dst for the + * preconditioner application). The + * user should really know what she + * is doing when touching this flag. */ - double nonzero_starting; + bool nonzero_starting; }; /** -- 2.39.5