vectorn.h

/*
 *  Copyright (C) 2004-2024 Edward F. Valeev
 *
 *  This file is part of Libint compiler.
 *
 *  Libint compiler 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  Libint compiler 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 Libint compiler.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#ifndef _libint2_src_bin_libint_boostutil_h_
#define _libint2_src_bin_libint_boostutil_h_
 
#include <boost/tuple/tuple.hpp>
 
namespace libint2 {
 
template <typename T, int N>
class VectorN {
 public:
  VectorN() {
    for (int i = 0; i < N; ++i) data_[i] = T();
  }
  VectorN(const VectorN& a) {
    for (int i = 0; i < N; ++i) data_[i] = a.data_[i];
  }
 
  VectorN& operator+=(const VectorN& a) {
    for (int i = 0; i < N; ++i) data_[i] += a.data_[i];
    return *this;
  }
  VectorN& operator-=(const VectorN& a) {
    for (int i = 0; i < N; ++i) data_[i] -= a.data_[i];
    return *this;
  }
 
  T norm1() const {
    T result(0);
    for (int i = 0; i < N; ++i) result += abs(data_[i]);
    return result;
  }
 
  T& operator[](int i) {
    assert(i >= 0 && i < N);
    return data_[i];
  }
  const T& operator[](int i) const {
    assert(i >= 0 && i < N);
    return data_[i];
  }
 
 private:
  T data_[N];
};
 
template <typename T, int N>
VectorN<T, N> operator+(const VectorN<T, N>& a, const VectorN<T, N>& b) {
  VectorN<T, N> result(a);
  result += b;
  return result;
}
template <typename T, int N>
VectorN<T, N> operator-(const VectorN<T, N>& a, const VectorN<T, N>& b) {
  VectorN<T, N> result(a);
  result -= b;
  return result;
}
 
template <typename T, int N>
inline VectorN<T, N> unit_vector(int i) {
  assert(i >= 0 && i < N);
  VectorN<T, N> result;
  result[i] += 1;
  return result;
}
 
// useful typedefs
typedef VectorN<int, 3> IntVec3;
inline IntVec3 unit_intvec3(int i) { return unit_vector<int, 3>(i); }
inline bool ltzero(const IntVec3& a) {
  for (int xyz = 0; xyz < 3; ++xyz)
    if (a[xyz] < 0) return true;
  return false;
}
 
}  // namespace libint2
 
#endif /* header guard */