From: Martin Kronbichler Date: Fri, 27 Nov 2015 07:43:08 +0000 (+0100) Subject: Fix documention introduced in #1914 X-Git-Tag: v8.4.0-rc2~199^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ad38f5f00c8b0ba3dbf13c65f18eceec15b451c5;p=dealii.git Fix documention introduced in #1914 --- diff --git a/doc/news/changes.h b/doc/news/changes.h index 545f7031d6..ba93a5e553 100644 --- a/doc/news/changes.h +++ b/doc/news/changes.h @@ -437,9 +437,9 @@ inconvenience this causes.
    -
  1. Fixed: parallel::distributed::Vector now detects of the size of MPI +
  2. Fixed: parallel::distributed::Vector now detects if the size of MPI messages exceeds 2GB or if the local range exceeds the size of 32-bit - integers and throws an exception about unsupported range of operation. + integers and throws an exception informing about the unsupported sizes.
    (Martin Kronbichler, 2015/11/26)
  3. diff --git a/include/deal.II/lac/parallel_vector.h b/include/deal.II/lac/parallel_vector.h index a6881ace24..dbc39aa93b 100644 --- a/include/deal.II/lac/parallel_vector.h +++ b/include/deal.II/lac/parallel_vector.h @@ -144,7 +144,7 @@ namespace parallel * * This vector class is based on two different number types for indexing. * The so-called global index type encodes the overall size of the vector. - * Its type is types::global_dof_index. The largest possible + * Its type is types::global_dof_index. The largest possible * value is 2^32-1 or approximately four billion in case 64 * bit integers are disabled at configuration of deal.II (default case) or * 2^64-1 or approximately 10^19 if 64 bit @@ -152,18 +152,17 @@ namespace parallel * @ref GlobalDoFIndex for further information). * * The second relevant index type is the local index used within one MPI - * rank. As opposed to the global index, the implementation assumes - * 32-bit unsigned integers unconditionally. In other words, to actually - * use a vector with more than four billion entries, you need to use MPI - * with more than one rank (which in general is a safe assumption since - * four billion entries consume at least 16 GB of memory for floats or 32 - * GB of memory for doubles). If more than 4 billion local elements are - * present, the implementation tries to detect that, which triggers an - * exception will be thrown and aborts the code. Note, however, that the - * detection of overflow is tricky and the detection mechanism might fail - * in some circumstances. Therefore, it is strongly recommended to not - * rely on this class to detect the case if local elements are more than - * four billion. + * rank. As opposed to the global index, the implementation assumes 32-bit + * unsigned integers unconditionally. In other words, to actually use a + * vector with more than four billion entries, you need to use MPI with + * more than one rank (which in general is a safe assumption since four + * billion entries consume at least 16 GB of memory for floats or 32 GB of + * memory for doubles) and enable 64-bit indices. If more than 4 billion + * local elements are present, the implementation tries to detect that, + * which triggers an exception and aborts the code. Note, however, that + * the detection of overflow is tricky and the detection mechanism might + * fail in some circumstances. Therefore, it is strongly recommended to + * not rely on this class to automatically detect the unsupported case. * * @author Katharina Kormann, Martin Kronbichler, 2010, 2011 */