103 lines
3 KiB
C++
103 lines
3 KiB
C++
/* Copyright (C) 2004-2013 MBSim Development Team
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Code was converted for the Bullet Continuous Collision Detection and Physics Library
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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//The original version is here
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//https://code.google.com/p/mbsim-env/source/browse/trunk/kernel/mbsim/numerics/linear_complementarity_problem/lemke_algorithm.cc
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//This file is re-distributed under the ZLib license, with permission of the original author (Kilian Grundl)
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//Math library was replaced from fmatvec to a the file src/LinearMath/btMatrixX.h
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//STL/std::vector replaced by btAlignedObjectArray
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#ifndef BT_NUMERICS_LEMKE_ALGORITHM_H_
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#define BT_NUMERICS_LEMKE_ALGORITHM_H_
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#include "LinearMath/btMatrixX.h"
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#include <vector> //todo: replace by btAlignedObjectArray
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class btLemkeAlgorithm
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{
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public:
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btLemkeAlgorithm(const btMatrixXu& M_, const btVectorXu& q_, const int& DEBUGLEVEL_ = 0) : DEBUGLEVEL(DEBUGLEVEL_)
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{
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setSystem(M_, q_);
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}
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/* GETTER / SETTER */
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/**
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* \brief return info of solution process
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*/
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int getInfo()
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{
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return info;
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}
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/**
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* \brief get the number of steps until the solution was found
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*/
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int getSteps(void)
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{
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return steps;
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}
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/**
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* \brief set system with Matrix M and vector q
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*/
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void setSystem(const btMatrixXu& M_, const btVectorXu& q_)
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{
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m_M = M_;
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m_q = q_;
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}
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/***************************************************/
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/**
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* \brief solve algorithm adapted from : Fast Implementation of Lemke’s Algorithm for Rigid Body Contact Simulation (John E. Lloyd)
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*/
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btVectorXu solve(unsigned int maxloops = 0);
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virtual ~btLemkeAlgorithm()
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{
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}
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protected:
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int findLexicographicMinimum(const btMatrixXu& A, const int& pivotColIndex);
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bool LexicographicPositive(const btVectorXu& v);
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void GaussJordanEliminationStep(btMatrixXu& A, int pivotRowIndex, int pivotColumnIndex, const btAlignedObjectArray<int>& basis);
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bool greaterZero(const btVectorXu& vector);
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bool validBasis(const btAlignedObjectArray<int>& basis);
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btMatrixXu m_M;
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btVectorXu m_q;
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/**
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* \brief number of steps until the Lemke algorithm found a solution
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*/
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unsigned int steps;
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/**
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* \brief define level of debug output
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*/
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int DEBUGLEVEL;
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/**
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* \brief did the algorithm find a solution
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*
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* -1 : not successful
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* 0 : successful
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*/
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int info;
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};
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#endif /* BT_NUMERICS_LEMKE_ALGORITHM_H_ */
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