From: Luca Heltai Date: Mon, 29 Jun 2020 12:52:46 +0000 (+0200) Subject: Added unit_to_real and real_to_unit to BoundingBox X-Git-Tag: v9.3.0-rc1~1327^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c379131f60750ec960c65067d34849b6c3ef72d2;p=dealii.git Added unit_to_real and real_to_unit to BoundingBox --- diff --git a/doc/news/changes/minor/20200629LucaHeltai b/doc/news/changes/minor/20200629LucaHeltai new file mode 100644 index 0000000000..e187db4982 --- /dev/null +++ b/doc/news/changes/minor/20200629LucaHeltai @@ -0,0 +1,5 @@ +New: BoundingBox::real_to_unit() and BoundingBox::unit_to_real() allow one to +apply both the direct and the inverse transformation that are needed to map the +unit bounding box to the current box, and viceversa. +
+(Luca Heltai, 2020/06/29) diff --git a/include/deal.II/base/bounding_box.h b/include/deal.II/base/bounding_box.h index 62bdbbc9d7..36d515d40e 100644 --- a/include/deal.II/base/bounding_box.h +++ b/include/deal.II/base/bounding_box.h @@ -263,6 +263,28 @@ public: BoundingBox cross_section(const unsigned int direction) const; + /** + * Apply the affine transformation that transforms this BoundingBox to a unit + * BoundingBox object. + * + * If $B$ is this bounding box, and $\hat{B}$ is the unit bounding box, + * compute the affine mapping that satisfies $G(B) = \hat{B}$ and apply it to + * @p point. + */ + Point + real_to_unit(const Point &point) const; + + /** + * Apply the affine transformation that transforms the unit BoundingBox object + * to this object. + * + * If $B$ is this bounding box, and $\hat{B}$ is the unit bounding box, + * compute the affine mapping that satisfies $F(\hat{B}) = B$ and apply it to + * @p point. + */ + Point + unit_to_real(const Point &point) const; + /** * Boost serialization function */ diff --git a/source/base/bounding_box.cc b/source/base/bounding_box.cc index c071e52b32..73ff6d088a 100644 --- a/source/base/bounding_box.cc +++ b/source/base/bounding_box.cc @@ -315,6 +315,35 @@ BoundingBox::cross_section(const unsigned int direction) const +template +Point +BoundingBox::real_to_unit( + const Point &point) const +{ + auto unit = point; + const auto diag = boundary_points.second - boundary_points.first; + unit -= boundary_points.first; + for (unsigned int d = 0; d < spacedim; ++d) + unit[d] /= diag[d]; + return unit; +} + + + +template +Point +BoundingBox::unit_to_real( + const Point &point) const +{ + auto real = boundary_points.first; + const auto diag = boundary_points.second - boundary_points.first; + for (unsigned int d = 0; d < spacedim; ++d) + real[d] += diag[d] * point[d]; + return real; +} + + + template BoundingBox create_unit_bounding_box() diff --git a/tests/base/bounding_box_7.cc b/tests/base/bounding_box_7.cc new file mode 100644 index 0000000000..b0a2fe2e41 --- /dev/null +++ b/tests/base/bounding_box_7.cc @@ -0,0 +1,85 @@ +// --------------------------------------------------------------------- +// +// Copyright (C) 2015 - 2020 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. +// +// --------------------------------------------------------------------- + +// Test the following functions of the BoundingBox class +// unit_to_real +// real_to_unit + +#include +#include +#include + +#include +#include + +#include "../tests.h" + +using namespace dealii; + +using iota = std_cxx20::ranges::iota_view; + +template +void +test() +{ + const unsigned int n_boxes = 3; + const unsigned int n_points = 3; + + const auto unit_box = create_unit_bounding_box(); + + for (auto i : iota(0, n_boxes)) + { + const auto box = random_box(); + // Check that all vertices get transformed correctly + for (auto v : iota(0, GeometryInfo::vertices_per_cell)) + { + const auto vertex = unit_box.vertex(v); + const auto real_vertex = box.unit_to_real(vertex); + if (real_vertex.distance(box.vertex(v)) > 1e-10) + deallog << "Error: " << vertex << " -> " << real_vertex + << " != " << box.vertex(v) << std::endl; + + const auto unit_vertex = box.real_to_unit(real_vertex); + if (unit_vertex.distance(vertex) > 1e-10) + deallog << "Error: " << real_vertex << " -> " << unit_vertex + << " != " << vertex << std::endl; + } + + // Now check random points + for (auto j : iota(0, n_points)) + { + const auto unit_point = random_point(); + const auto real_point = box.unit_to_real(unit_point); + const auto real_to_unit = box.real_to_unit(real_point); + + if (real_to_unit.distance(unit_point) > 1e-10) + deallog << "Error: " << unit_point << " -> " << real_point << " -> " + << real_to_unit << " != " << unit_point << std::endl; + } + } + deallog << "Spacedim " << dim << " OK" << std::endl; +} + + + +int +main() +{ + initlog(); + + test<1>(); + test<2>(); + test<3>(); +} diff --git a/tests/base/bounding_box_7.output b/tests/base/bounding_box_7.output new file mode 100644 index 0000000000..a44332f33c --- /dev/null +++ b/tests/base/bounding_box_7.output @@ -0,0 +1,4 @@ + +DEAL::Spacedim 1 OK +DEAL::Spacedim 2 OK +DEAL::Spacedim 3 OK