From: Niklas Fehn Date: Mon, 14 Oct 2019 15:37:13 +0000 (+0200) Subject: new function DataOutInterface::write_vtu_with_pvtu_record() to avoid reimplementing... X-Git-Tag: v9.2.0-rc1~974^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F8904%2Fhead;p=dealii.git new function DataOutInterface::write_vtu_with_pvtu_record() to avoid reimplementing the same code again and again --- diff --git a/doc/news/changes/minor/20191014NiklasFehn b/doc/news/changes/minor/20191014NiklasFehn new file mode 100644 index 0000000000..9b4515535e --- /dev/null +++ b/doc/news/changes/minor/20191014NiklasFehn @@ -0,0 +1,6 @@ +New: The function DataOutInterface::write_vtu_with_pvtu_record() combines +write_vtu() and write_pvtu_record() into a single function and generates +the file extensions with counter, processor ID, and .vtu/.pvtu ending +automatically. +
+(Niklas Fehn, 2019/10/14) diff --git a/include/deal.II/base/data_out_base.h b/include/deal.II/base/data_out_base.h index 0c91ef2e9c..57713c593f 100644 --- a/include/deal.II/base/data_out_base.h +++ b/include/deal.II/base/data_out_base.h @@ -3030,6 +3030,56 @@ public: write_pvtu_record(std::ostream & out, const std::vector &piece_names) const; + /** + * This function combines DataOutInterface::write_vtu(), or + * DataOutInterface::write_vtu_in_parallel(), with + * DataOutInterface::write_pvtu_record(). It automatically constructs + * the filename of the generated output files and writes a pvtu file. + * A specified @p directory and a @p filename_without_extension + * form the first part of the filename. The filename is then extended with + * a @p counter labeling the current timestep/iteration/etc., the processor ID, + * and finally the .vtu/.pvtu ending. Since the number of timesteps to be + * written depends on the application, the number of digits to be reserved in + * the filename can be specified as parameter @p n_digits_for_counter, and the number + * is not padded with leading zeros if this parameter is left at its default + * value numbers::invalid_unsigned_int. If more than one file identifier + * is needed (e.g. time step number and iteration counter of solver), the + * last identifier is used as @p counter, while all other identifiers have to be + * added to @p filename_without_extension when calling this function. In a + * parallel setting, several files are typically written per time step. The + * number of files written in parallel depends on the number of MPI processes + * (see parameter @p mpi_communicator with default value MPI_COMM_WORLD), and a + * specified number of @p n_groups with default value 0. The background is that + * VTU file output supports grouping files from several CPUs into a given + * number of files using MPI I/O when writing on a parallel filesystem. The + * default value of @p n_groups is 0, meaning that every MPI rank will write one + * file. A value of 1 will generate one big file containing the solution over + * the whole domain, while a larger value will create @p n_groups files (but not + * more than there are MPI ranks). Note that only one processor needs to + * generate the .pvtu file, where processor zero is chosen to take over this + * job. + * + * The return value is the filename of the master file for the pvtu record. + * + * @note The code simply combines the strings @p directory and + * @p filename_without_extension, i.e., the user has to make sure that + * @p directory contains a trailing character, e.g. "/", that separates the + * directory from the filename. + * + * @note Use an empty string "" for the first argument if output is to be + * written in the current working directory. + * + * @author Niklas Fehn, Martin Kronbichler, 2019 + */ + std::string + write_vtu_with_pvtu_record( + const std::string &directory, + const std::string &filename_without_extension, + const unsigned int counter, + const unsigned int n_digits_for_counter = numbers::invalid_unsigned_int, + const MPI_Comm & mpi_communicator = MPI_COMM_WORLD, + const unsigned int n_groups = 0) const; + /** * Obtain data through get_patches() and write it to out in SVG * format. See DataOutBase::write_svg. diff --git a/source/base/data_out_base.cc b/source/base/data_out_base.cc index 8f00b4fbc5..af277a330e 100644 --- a/source/base/data_out_base.cc +++ b/source/base/data_out_base.cc @@ -7544,6 +7544,83 @@ DataOutInterface::write_pvtu_record( } +template +std::string +DataOutInterface::write_vtu_with_pvtu_record( + const std::string &directory, + const std::string &filename_without_extension, + const unsigned int counter, + const unsigned int n_digits_for_counter, + const MPI_Comm & mpi_communicator, + const unsigned int n_groups) const +{ + const unsigned int rank = Utilities::MPI::this_mpi_process(mpi_communicator); + const unsigned int n_ranks = + Utilities::MPI::n_mpi_processes(mpi_communicator); + const unsigned int n_files_written = + (n_groups == 0 || n_groups > n_ranks) ? n_ranks : n_groups; + + const unsigned int n_digits = + static_cast(std::ceil(std::log10(std::fabs(n_files_written)))); + + const unsigned int color = rank % n_files_written; + const std::string filename = + directory + filename_without_extension + "_" + + Utilities::int_to_string(counter, n_digits_for_counter) + "." + + Utilities::int_to_string(color, n_digits) + ".vtu"; + + if (n_groups == 0 || n_groups > n_ranks) + { + // every processor writes one file + std::ofstream output(filename.c_str()); + this->write_vtu(output); + } + else if (n_groups == 1) + { + // write only a single data file in parallel + this->write_vtu_in_parallel(filename.c_str(), mpi_communicator); + } + else + { +#ifdef DEAL_II_WITH_MPI + // write n_groups data files + MPI_Comm comm_group; + int ierr = MPI_Comm_split(mpi_communicator, color, rank, &comm_group); + AssertThrowMPI(ierr); + this->write_vtu_in_parallel(filename.c_str(), comm_group); + ierr = MPI_Comm_free(&comm_group); + AssertThrowMPI(ierr); +#else + AssertThrow(false, ExcMessage("Logical error. Should not arrive here.")); +#endif + } + + // write pvtu record + const std::string filename_master = + filename_without_extension + "_" + + Utilities::int_to_string(counter, n_digits_for_counter) + ".pvtu"; + + if (rank == 0) + { + std::vector filename_vector; + for (unsigned int i = 0; i < n_files_written; ++i) + { + const std::string filename = + filename_without_extension + "_" + + Utilities::int_to_string(counter, n_digits_for_counter) + "." + + Utilities::int_to_string(i, n_digits) + ".vtu"; + + filename_vector.emplace_back(filename); + } + + std::ofstream master_output((directory + filename_master).c_str()); + this->write_pvtu_record(master_output, filename_vector); + } + + return filename_master; +} + + template void