lumosquad/CELL.h
2025-07-26 22:14:37 +02:00

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///////////////////////////////////////////////////////////////////////////////////
// File : CELL.h
///////////////////////////////////////////////////////////////////////////////////
//
// LumosQuad - A Lightning Generator
// Copyright 2007
// The University of North Carolina at Chapel Hill
//
///////////////////////////////////////////////////////////////////////////////////
//
// 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// The University of North Carolina at Chapel Hill makes no representations
// about the suitability of this software for any purpose. It is provided
// "as is" without express or implied warranty.
//
// Permission to use, copy, modify and distribute this software and its
// documentation for educational, research and non-profit purposes, without
// fee, and without a written agreement is hereby granted, provided that the
// above copyright notice and the following three paragraphs appear in all
// copies.
//
// THE UNIVERSITY OF NORTH CAROLINA SPECIFICALLY DISCLAIM ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN
// "AS IS" BASIS, AND THE UNIVERSITY OF NORTH CAROLINA HAS NO OBLIGATION TO
// PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
//
// Please send questions and comments about LumosQuad to kim@cs.unc.edu.
//
///////////////////////////////////////////////////////////////////////////////////
//
// This program uses OpenEXR, which has the following restrictions:
//
// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Industrial Light & Magic nor the names of
// its contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
#ifndef CELL_H
#define CELL_H
#include <cstdlib>
//////////////////////////////////////////////////////////////////////
/// \enum Possible states of the cell in the DBM simulation
//////////////////////////////////////////////////////////////////////
enum CELL_STATE {EMPTY, NEGATIVE, POSITIVE, REPULSOR, ATTRACTOR};
//////////////////////////////////////////////////////////////////////
/// \brief Basic cell data structure of the quadtree
//////////////////////////////////////////////////////////////////////
class CELL
{
public:
//! normal cell constructor
CELL(float north,
float east,
float south,
float west,
CELL* parent = NULL,
int depth = 0);
//! ghost cell constructor
CELL(int depth = 0);
//! destructor
~CELL();
//! The children of the node in the quadtree
/*!
Winding order of children is:
\verbatim
_________
| | |
| 0 | 1 |
|___|___|
| | |
| 3 | 2 |
|___|___|
\endverbatim */
CELL* children[4];
//! The physical bounds of the current grid cell
/*!
Winding order of bounds is:
\verbatim
0 - north
1 - east
2 - south
3 - west
\endverbatim */
float bounds[4];
//! The neighbors in the balanced quadtree
/*!
winding order of the neighbors is:
\verbatim
| 0 | 1 |
____|____|____|_____
| |
7 | | 2
____| |_____
| |
6 | | 3
____|_________|_____
| | |
| 5 | 4 |
\endverbatim
Neighbors 0,2,4,6 should always exist. Depending on
if the neighbor is on a lower refinement level,
neighbors 1,3,5,7 may or may not exist. If they are not
present, the pointer value should ne NULL. */
CELL* neighbors[8];
//! Poisson stencil coefficients
/*!
winding order of the stencil coefficients:
\verbatim
| 0 | 1 |
____|____|____|_____
| |
7 | | 2
____| 8 |_____
| |
6 | | 3
____|_________|_____
| | |
| 5 | 4 |
\endverbatim
Stencils 0,2,4,6 should always exist. Depending on
if the neighbor is on a lower refinement level,
stencils 1,3,5,7 may or may not exist. If they are not
present, the pointer value should ne NULL. */
float stencil[9];
float center[2]; ///< center of the cell
int depth; ///< current tree depth
bool candidate; ///< already a member of candidate list?
CELL* parent; ///< parent node in the quadtree
CELL_STATE state; ///< DBM state of the cell
void refine(); ///< subdivide the cell
////////////////////////////////////////////////////////////////
// solver-related variables
////////////////////////////////////////////////////////////////
bool boundary; ///< boundary node to include in the solver?
float potential; ///< current electric potential
float b; ///< rhs of the linear system
float residual; ///< residual in the linear solver
int index; ///< lexicographic index for the solver
////////////////////////////////////////////////////////////////
// neighbor lookups
////////////////////////////////////////////////////////////////
CELL* northNeighbor(); ///< lookup northern neighbor
CELL* southNeighbor(); ///< lookup southern neighbor
CELL* westNeighbor(); ///< lookup western neighbor
CELL* eastNeighbor(); ///< lookup eastern neighbor
};
#endif