From: Niklas Fehn <fehn@lnm.mw.tum.de>
Date: Fri, 5 Jun 2020 17:57:53 +0000 (+0200)
Subject: add docu and test, make implementation more readable
X-Git-Tag: v9.3.0-rc1~1480^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f5e07b2b892ce725406faeb357b72dbdb4a3f81c;p=dealii.git

add docu and test, make implementation more readable
---

diff --git a/include/deal.II/base/bounding_box.h b/include/deal.II/base/bounding_box.h
index f97673e26e..8d4d7f2536 100644
--- a/include/deal.II/base/bounding_box.h
+++ b/include/deal.II/base/bounding_box.h
@@ -182,7 +182,10 @@ public:
   merge_with(const BoundingBox<spacedim, Number> &other_bbox);
 
   /**
-   * Return true if the point is inside the Bounding Box, false otherwise.
+   * Return true if the point is inside the Bounding Box, false otherwise. The
+   * parameter @p tolerance is a factor by which the bounding box is enlarged
+   * relative to the dimensions of the bounding box in order to determine in a
+   * numerically robust way whether the point is inside.
    */
   bool
   point_inside(
diff --git a/source/base/bounding_box.cc b/source/base/bounding_box.cc
index 72f097aa07..c071e52b32 100644
--- a/source/base/bounding_box.cc
+++ b/source/base/bounding_box.cc
@@ -27,10 +27,12 @@ BoundingBox<spacedim, Number>::point_inside(const Point<spacedim, Number> &p,
       // Bottom left-top right convention: the point is outside if it's smaller
       // than the first or bigger than the second boundary point The bounding
       // box is defined as a closed set
-      if (tolerance * std::abs(this->boundary_points.first[i] + p[i]) <
-            this->boundary_points.first[i] - p[i] ||
-          tolerance * std::abs(this->boundary_points.second[i] + p[i]) <
-            p[i] - this->boundary_points.second[i])
+      if ((p[i] < this->boundary_points.first[i] -
+                    tolerance * std::abs(this->boundary_points.second[i] -
+                                         this->boundary_points.first[i])) ||
+          (p[i] > this->boundary_points.second[i] +
+                    tolerance * std::abs(this->boundary_points.second[i] -
+                                         this->boundary_points.first[i])))
         return false;
     }
   return true;
diff --git a/tests/base/bounding_box_1.cc b/tests/base/bounding_box_1.cc
index 56a0a43ccc..7c4f9486a3 100644
--- a/tests/base/bounding_box_1.cc
+++ b/tests/base/bounding_box_1.cc
@@ -116,6 +116,20 @@ test_unitary()
           << b.point_inside(p3) << " " << b.point_inside(p1 + p2) << " "
           << b.point_inside(p2 + p3) << " " << b.point_inside(p1 + p3) << " "
           << std::endl;
+
+  double eps = std::numeric_limits<double>::epsilon();
+  AssertThrow(b.point_inside(Point<3>(0.0, 0.0, 1.0 + 1.0 * eps), 10. * eps) ==
+                true,
+              ExcMessage("failed."));
+  AssertThrow(b.point_inside(Point<3>(0.0, 0.0, 1.0 + 10. * eps), 1.0 * eps) ==
+                false,
+              ExcMessage("failed."));
+  AssertThrow(b.point_inside(Point<3>(0.0 - 1.0 * eps, 0.0, 0.0), 10. * eps) ==
+                true,
+              ExcMessage("failed."));
+  AssertThrow(b.point_inside(Point<3>(0.0 - 10. * eps, 0.0, 0.0), 1.0 * eps) ==
+                false,
+              ExcMessage("failed."));
 }
 
 int