From 850ffc5b2f2d26c9e4df4bff1191d2ff9bb99e8a Mon Sep 17 00:00:00 2001 From: Peter Munch Date: Thu, 8 Dec 2022 19:16:23 +0100 Subject: [PATCH] Modified Gram-Schmidt: add docu --- doc/news/changes/minor/20221208Munch | 6 ++++++ include/deal.II/lac/solver_gmres.h | 5 ++++- 2 files changed, 10 insertions(+), 1 deletion(-) create mode 100644 doc/news/changes/minor/20221208Munch diff --git a/doc/news/changes/minor/20221208Munch b/doc/news/changes/minor/20221208Munch new file mode 100644 index 0000000000..e90bef2f41 --- /dev/null +++ b/doc/news/changes/minor/20221208Munch @@ -0,0 +1,6 @@ +New: SolverGMRES now also supports classical Gram-Schmidt orthonormalization +alongside to the existing modified Gram-Schmidt algorithm. This +allows to reduce the cost of vector operations in terms of +communication latency and memory transfer significantly. +
+(Peter Munch, Martin Kronbichler, 2022/12/08) diff --git a/include/deal.II/lac/solver_gmres.h b/include/deal.II/lac/solver_gmres.h index 76bc111c58..70a3b164a1 100644 --- a/include/deal.II/lac/solver_gmres.h +++ b/include/deal.II/lac/solver_gmres.h @@ -204,7 +204,10 @@ public: */ modified_gram_schmidt, /** - * Use classical Gram-Schmidt algorithm. + * Use classical Gram-Schmidt algorithm. Since this approach works on + * multi-vectors and performs a global reduction only once, it is + * more efficient than the modified Gram-Schmidt algorithm. + * However, it might be numerically unstable. */ classical_gram_schmidt }; -- 2.39.5