[common] add math header

frackit/common/math.hh

+// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// vi: set et ts=4 sw=4 sts=4:
+/*****************************************************************************
+ *   See the file COPYING for full copying permissions.                      *
+ *                                                                           *
+ *   This program is free software: you can redistribute it and/or modify    *
+ *   it under the terms of the GNU General Public License as published by    *
+ *   the Free Software Foundation, either version 2 of the License, or       *
+ *   (at your option) any later version.                                     *
+ *                                                                           *
+ *   This program is distributed in the hope that it will be useful,         *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the            *
+ *   GNU General Public License for more details.                            *
+ *                                                                           *
+ *   You should have received a copy of the GNU General Public License       *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.   *
+ *****************************************************************************/
+/*!
+ * \file
+ * \brief \todo TODO doc me.
+ */
+#ifndef FRACKIT_MATH_HH
+#define FRACKIT_MATH_HH
+
+#include <frackit/geometry/vector.hh>
+#include <frackit/geometry/precision.hh>
+
+namespace Frackit {
+
+/*!
+ * \brief \todo TODO doc me.
+ */
+template<class ctype>
+Vector<ctype, 3> crossProduct(const Vector<ctype, 3>& v1,
+                              const Vector<ctype, 3>& v2)
+{
+    return { v1.y()*v2.z() - v1.z()*v2.y(),
+             v1.z()*v2.x() - v1.x()*v2.z(),
+             v1.x()*v2.y() - v1.y()*v2.x() };
+}
+
+/*!
+ * \brief \todo TODO doc me.
+ */
+template<class ctype>
+ctype boxProduct(const Vector<ctype, 3>& v1,
+                 const Vector<ctype, 3>& v2,
+                 const Vector<ctype, 3>& v3)
+{ return v1*crossProduct(v2, v3); }
+
+/*!
+ * \brief \todo TODO doc me.
+ */
+template<class ctype>
+bool isRightHandSystem(const Vector<ctype, 3>& v1,
+                       const Vector<ctype, 3>& v2,
+                       const Vector<ctype, 3>& v3)
+{
+    assert(std::abs(boxProduct(v1, v2, v3)) > Precision<ctype>::confusion());
+    return boxProduct(v1, v2, v3) > 0.0;
+}
+
+} // end namespace Frackit
+
+#endif // FRACKIT_MATH_HH