qpoint.cpp

来自「算断裂的」· C++ 代码 · 共 99 行

// ------------------------------------------------------------------
// qpoint.cpp
//
// This file contains routines for math with points in R^2 and R^3
// ------------------------------------------------------------------
// Copyright (c) 1999 by Cornell University.  All rights reserved.
// 
// See the accompanying file 'Copyright' for authorship information,
// the terms of the license governing this software, and disclaimers
// concerning this software.
// ------------------------------------------------------------------
// This file is part of the QMG software.  
// Version 2.0 of QMG, release date September 3, 1999
// ------------------------------------------------------------------



#include "qpoint.h"



// L2 normalization of a vector.

void QMG::Point::normalize() {
  Real s = 0.0;
  {
    for (int i = 0; i < di_; ++i)
      s += coords_[i] * coords_[i];
  }
  
  s = sqrt(s);
  {
    for (int i = 0; i < di_; ++i)
      coords_[i] /= s;
  }
}


QMG::Real QMG::Point::l2norm() const {
  Real returnval = 0;
  for (int i = 0; i < di_; ++i)
    returnval += coords_[i] * coords_[i];
  return sqrt(returnval);
}

QMG::Point QMG::Point::cross_product(const Point& a, const Point& b) {
  Point returnval;
  returnval[0] = (a.coords_[1] * b.coords_[2] - a.coords_[2] * b.coords_[1]);
  returnval[1] = (a.coords_[2] * b.coords_[0] - a.coords_[0] * b.coords_[2]);
  returnval[2] = (a.coords_[0] * b.coords_[1] - a.coords_[1] * b.coords_[0]);
  return returnval;
}


QMG::Point QMG::Point::subtract(const Point& a, const Point& b) {
  Point returnval;
  for (int i = 0; i < di_; ++i)
    returnval[i] = a.coords_[i] - b.coords_[i];
  return returnval;
}



QMG::ostream& operator<<(QMG::ostream& os, const QMG::Point& pt) {
  for (int i = 0; i < pt.embedded_dim(); ++i) {
    os << pt[i] << " ";
  }
  return os;
}


QMG::Real QMG::Point::inner_product(const Point& a, const Point& b) {
  Real ip = 0;
  for (int i = 0; i < di_; ++i)
    ip += a.coords_[i] * b.coords_[i];
  return ip;
}


QMG::Real QMG::Point::l1dist(const Point& a, const Point& b) {
  Real d = 0;
  for (int i = 0; i < di_; ++i)
    d += fabs(a.coords_[i] - b.coords_[i]);
  return d;
}

QMG::Real QMG::Point::l2dist(const Point& a, const Point& b, int dim) {
  Real d = 0;
  Real t;
  for (int i = 0; i < dim; ++i) {
    t = a.coords_[i] - b.coords_[i];
    d += t * t;
  }
  return sqrt(d);
}


int QMG::Point::di_;