From: Wolfgang Bangerth Date: Thu, 16 Jan 2020 16:26:36 +0000 (-0700) Subject: Observe that passing a lambda function to set_cell_selection() also works. X-Git-Tag: v9.2.0-rc1~657^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F9287%2Fhead;p=dealii.git Observe that passing a lambda function to set_cell_selection() also works. --- diff --git a/include/deal.II/numerics/data_out.h b/include/deal.II/numerics/data_out.h index 5df322a5aa..a735adc9e9 100644 --- a/include/deal.II/numerics/data_out.h +++ b/include/deal.II/numerics/data_out.h @@ -367,6 +367,23 @@ public: * object given as argument. A typical way to generate the argument * is via the make_filtered_iterator() function. * + * Alternatively, since FilteredIterator objects can be created from + * just a predicate (i.e., a function object that returns a `bool`), it is + * possible to call this function with just a lambda function, which will then + * automatically be converted to a FilteredIterator object. For example, the + * following piece of code works: + * @code + * DataOut data_out; + * data_out.set_cell_selection( + * [](const typename Triangulation::cell_iterator &cell) { + * return (!cell->has_children() && cell->subdomain_id() == 0); + * }); + * @endcode + * In this case, the lambda function selects all of those cells that are + * @ref GlossActive "active" + * and whose subdomain id is zero. These will then be the only cells on + * which output is generated. + * * @note Not all filters will result in subsets of cells for which * output can actually be generated. For example, if you are working * on parallel meshes where data is only available on some cells, diff --git a/tests/data_out/data_out_08_set_cell_selection_03.cc b/tests/data_out/data_out_08_set_cell_selection_03.cc new file mode 100644 index 0000000000..2299573b45 --- /dev/null +++ b/tests/data_out/data_out_08_set_cell_selection_03.cc @@ -0,0 +1,124 @@ +// --------------------------------------------------------------------- +// +// Copyright (C) 2003 - 2018 by the deal.II authors +// +// This file is part of the deal.II library. +// +// The deal.II library is free software; you can use it, redistribute +// it, and/or modify it under the terms of the GNU Lesser General +// Public License as published by the Free Software Foundation; either +// version 2.1 of the License, or (at your option) any later version. +// The full text of the license can be found in the file LICENSE.md at +// the top level directory of deal.II. +// +// --------------------------------------------------------------------- + + +// This test is an adaptation of the _08 test, but using the +// DataOut::set_cell_selection() function with the FilteredIterator +// argument instead of overloading member functions. Since +// FilteredIterators can be created directly from lambda functions, we +// check that passing a lambda function to set_cell_selection() as +// argument works as well. +// +// Because the _08 test is eventually going away (as it uses +// deprecated functions), here is the description of that test: +// .................... +// This test documents two unrelated bugs in DataOut when used with a Filter (by +// deriving from DataOut): +// 1. The patch index computation in data_out.cc is wrong and causes an SIGV (or +// an Assert after adding that): +/* +466: -------------------------------------------------------- +466: An error occurred in line <306> of file + in function +466: void dealii::DataOut::build_one_patch(const +std::pair::cell_iterator, unsigned int>*, +dealii::internal::DataOut::ParallelData&, dealii::DataOutBase::Patch&, dealii::DataOut::CurvedCellRegion, +std::vector >&) [with int dim = 2, DoFHandlerType = +dealii::DoFHandler<2>, typename dealii::DataOut_DoFData::cell_iterator = +dealii::TriaIterator >] 466: The violated condition +was: 466: cell_and_index->second < patches.size() 466: The name and call +sequence of the exception was: 466: ExcInternalError() +*/ +// 2. DataOut used begin_active() instead of first_cell() in two places which +// caused a wrong patch to be generated when the first active cell is not picked +// by the filter. + +#include +#include +#include + +#include + +#include +#include +#include + +#include + +#include + +#include "../tests.h" + + + +template +void +check() +{ + Triangulation tria; + GridGenerator::hyper_cube(tria, 0., 1.); + tria.refine_global(1); + + Vector cell_data(4); + for (unsigned int i = 0; i < 4; ++i) + cell_data(i) = i * 1.0; + + // this should skip the first cell + typename Triangulation::active_cell_iterator it = tria.begin_active(); + it->set_subdomain_id(1); + + FE_DGQ fe(0); + DoFHandler dof_handler(tria); + dof_handler.distribute_dofs(fe); + + // we pick only subdomain==0 which will + // skip the first of the four cells + DataOut data_out; + data_out.set_cell_selection( + [](const typename Triangulation::cell_iterator &cell) { + return (!cell->has_children() && cell->subdomain_id() == 0); + }); + + + data_out.attach_dof_handler(dof_handler); + + data_out.add_data_vector(cell_data, + "cell_data", + DataOut::type_cell_data); + data_out.build_patches(); + + data_out.write_deal_II_intermediate(deallog.get_file_stream()); + + deallog << "OK" << std::endl; +} + +int +main(int argc, char **argv) +{ + std::ofstream logfile("output"); + deallog << std::setprecision(2); + logfile << std::setprecision(2); + deallog.attach(logfile); + + check<2>(); + + return 0; +} diff --git a/tests/data_out/data_out_08_set_cell_selection_03.output b/tests/data_out/data_out_08_set_cell_selection_03.output new file mode 100644 index 0000000000..bd4f3f7361 --- /dev/null +++ b/tests/data_out/data_out_08_set_cell_selection_03.output @@ -0,0 +1,38 @@ + +2 2 +[deal.II intermediate format graphics data] +[written by deal.II x.y.z] +[Version: 3] +1 +cell_data +3 +[deal.II intermediate Patch<2,2>] +0.50 0.0 1.0 0.0 1.0 0.50 0.50 0.50 +4294967295 4294967295 4294967295 2 +0 1 +0 +1 4 +1.0 1.0 1.0 1.0 + + +[deal.II intermediate Patch<2,2>] +0.0 0.50 0.50 0.50 0.50 1.0 0.0 1.0 +4294967295 2 4294967295 4294967295 +1 1 +0 +1 4 +2.0 2.0 2.0 2.0 + + +[deal.II intermediate Patch<2,2>] +0.50 0.50 1.0 0.50 1.0 1.0 0.50 1.0 +1 4294967295 0 4294967295 +2 1 +0 +1 4 +3.0 3.0 3.0 3.0 + + +0 + +DEAL::OK