From 94d3e79a8617f88dc0219cfdeedfa3147833719d Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Mon, 24 Jun 2019 14:43:36 +0200
Subject: Initialize at openlb-1-3

---
 src/utilities/vectorHelpers.h | 276 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 276 insertions(+)
 create mode 100644 src/utilities/vectorHelpers.h

(limited to 'src/utilities/vectorHelpers.h')

diff --git a/src/utilities/vectorHelpers.h b/src/utilities/vectorHelpers.h
new file mode 100644
index 0000000..17453dd
--- /dev/null
+++ b/src/utilities/vectorHelpers.h
@@ -0,0 +1,276 @@
+/*  This file is part of the OpenLB library
+ *
+ *  Copyright (C) 2013, 2014 Lukas Baron, Mathias J. Krause
+ *  E-mail contact: info@openlb.net
+ *  The most recent release of OpenLB can be downloaded at
+ *  <http://www.openlb.net/>
+ *
+ *  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, write to the Free
+ *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA  02110-1301, USA.
+*/
+
+#ifndef VECTOR_HELPERS_H
+#define VECTOR_HELPERS_H
+
+#include<assert.h>
+#include<cmath>
+#include<vector>
+#include<string>
+#include<sstream>
+#include<limits>
+
+#include "io/ostreamManager.h"
+#include "core/vector.h"
+
+namespace olb {
+
+template<typename T, unsigned Size > class Vector;
+
+namespace util {
+
+
+/// return true if a is close to zero
+template <class T>
+inline bool nearZero(const T& a)
+{
+  if (a==T()) return true;
+  T EPSILON = std::numeric_limits<T>::epsilon();
+  if (a > -EPSILON && a < EPSILON) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+template <class T>
+inline bool nearZero(const T& a, const T& epsilon)
+{
+  if (a > -epsilon && a < epsilon) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+template<typename T>
+inline bool approxEqual(const T& a, const T& b, const T& epsilon)
+{
+  if (a==b) return true;
+  return nearZero<T>(a - b, epsilon);
+}
+
+template<typename T>
+inline bool approxEqual(const T& a, const T& b)
+{
+  if (a==b) return true;
+  if (nearZero(a) && nearZero(b)) return true;
+  T EPSILON = std::numeric_limits<T>::epsilon()*4.*fabs(a);
+  return approxEqual(a,b,EPSILON);
+}
+
+template <class T>
+inline void copyN(T c[], const T a[], const unsigned dim)
+{
+  for (unsigned i=0; i<dim; i++) {
+    c[i] = a[i];
+  }
+}
+
+template <class T>
+inline void copy3(T c[], const T a[])
+{
+  for (unsigned i=0; i<3; i++) {
+    c[i] = a[i];
+  }
+}
+
+
+template <typename T>
+std::vector<T> fromVector3(const Vector<T,3>& vec)
+{
+  std::vector<T> v;
+  v.push_back(vec[0]);
+  v.push_back(vec[1]);
+  v.push_back(vec[2]);
+  return v;
+}
+template <typename T>
+std::vector<T> fromVector2(const Vector<T,2>& vec)
+{
+  std::vector<T> v;
+  v.push_back(vec[0]);
+  v.push_back(vec[1]);
+  return v;
+}
+
+
+/// l2 norm of a vector of arbitrary length
+template <typename T>
+T norm(const std::vector<T>& a)
+{
+  T v(0);
+  for (unsigned iD=0; iD<a.size(); iD++) {
+    v += a[iD]*a[iD];
+  }
+  v = sqrt(v);
+  return v;
+}
+
+/// l2 norm to the power of 2 of a vector of arbitrary length
+template <typename T>
+T norm2(const std::vector<T>& a)
+{
+  T v = T();
+  for (unsigned iD=0; iD<a.size(); iD++) {
+    v += a[iD]*a[iD];
+  }
+  return v;
+}
+
+/// dot product, only valid in 3d
+template <typename T>
+T dotProduct3D(const Vector<T,3>& a, const Vector<T,3>& b)
+{
+  return a[0]*b[0] + a[1]*b[1] + a[2]*b[2];
+}
+
+/// dot product, only valid in 2d
+template <typename T>
+T dotProduct2D(const Vector<T,2>& a, const Vector<T,2>& b)
+{
+  return a[0]*b[0] + a[1]*b[1];
+}
+
+/// returns a normalized vector, works for arbitrary lengths
+template <typename T>
+std::vector<T> normalize(const std::vector<T>& a)
+{
+  std::vector<T> out(a);
+  T scale = norm(a);
+  assert(scale>0);
+  for (unsigned int iDim=0; iDim<a.size(); iDim++) {
+    out[iDim] /= scale;
+  }
+  return out;
+}
+
+/// applies floor to each component of a vector
+template <typename T, unsigned Size>
+Vector<T,Size> floor(const Vector<T,Size>& a)
+{
+  Vector<T,Size> out;
+  for (unsigned int iDim=0; iDim < Size; ++iDim) {
+    out[iDim] = std::floor(a[iDim]);
+  }
+  return out;
+}
+
+/// applies ceil to each component of a vector
+template <typename T, unsigned Size>
+Vector<T,Size> ceil(const Vector<T,Size>& a)
+{
+  Vector<T,Size> out;
+  for (unsigned int iDim=0; iDim < Size; ++iDim) {
+    out[iDim] = std::ceil(a[iDim]);
+  }
+  return out;
+}
+
+/*
+/// algorithm by Möller–Trumbore (TODO add ref), implemented by Lucas Cruz and Mathias J. Krause
+/// returns true if there is an intersection of a triangle given by (point0, point1, point1) and a ray given by its origin and direction and computes the distance
+template <typename T>
+bool triangleIntersectionWithNormalDirection(const std::vector<T>& point0,
+    const std::vector<T>& point1, const std::vector<T>& point2,
+    const std::vector<T>& origin, const std::vector<T>& normalDirection,
+    T& distance)
+{
+  T EPSILON = std::numeric_limits<T>::epsilon();
+  std::vector<T> e1, e2;
+  std::vector<T> P, Q, TT;
+  T det, inv_det;
+  T t, u, v;
+  e1 = point1 - point0;
+  e2 = point2 - point0;
+  P = crossProduct3D(normalDirection, e2);
+  det = dotProduct3D(P, e1);
+  if (det > -EPSILON && det < EPSILON) {
+    return false;
+  }
+  inv_det = T(1) / det;
+  TT = origin - point0;
+  u = dotProduct3D(TT, P)*inv_det;
+  if (u < T() || u > T(1)) {
+    return false;
+  }
+  Q = crossProduct3D(TT, e1);
+  v = dotProduct3D(normalDirection, Q) * inv_det;
+  if (v < T() || u + v  > T(1)) {
+    return false;
+  }
+  t = dotProduct3D(e2, Q)*inv_det;
+  if (t > EPSILON) {
+    distance = t;
+    return true;
+  }
+  return false;
+}
+
+template <typename T>
+bool triangleIntersection(const std::vector<T>& point0, const std::vector<T>& point1, const std::vector<T>& point2, const std::vector<T>& origin, const std::vector<T>& direction, T& distance)
+{
+  std::vector<T> normalDirection(normalize(direction) );
+  return triangleIntersectionWithNormalDirection(point0, point1, point2, origin, normalDirection, distance );
+}
+*/
+template <typename T>
+std::vector<T> assign(T a, T b)
+{
+  std::vector<T> v1;
+  v1.push_back(a);
+  v1.push_back(b);
+  return v1;
+}
+
+template <typename T>
+std::vector<T> assign(T a, T b, T c)
+{
+  std::vector<T> v1;
+  v1.push_back(a);
+  v1.push_back(b);
+  v1.push_back(c);
+  return v1;
+}
+
+
+template<typename U>
+void print(U data, const std::string& name="", OstreamManager clout = OstreamManager(std::cout,"print"),
+  const char delimiter=',')
+{
+  static_assert(!std::is_integral<U>::value && !std::is_floating_point<U>::value, "passed integral or floating_point value to function print()");
+  if (name != "") {
+    clout << name << " = ";
+  }
+  for( auto& element : data ) {
+    clout << std::fixed << element << delimiter << ' ';
+  }
+  clout << std::endl;
+}
+
+
+} // namespace util
+} // namespace olb
+
+#endif
-- 
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