74 lines
2.9 KiB
C++
74 lines
2.9 KiB
C++
/*************************************************************************
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* *
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* Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith. *
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* All rights reserved. Email: russ@q12.org Web: www.q12.org *
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* *
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* This library is free software; you can redistribute it and/or *
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* modify it under the terms of *
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* The BSD-style license that is included with this library in *
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* the file LICENSE-BSD.TXT. *
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* *
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* This library is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files *
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* LICENSE.TXT and LICENSE-BSD.TXT for more details. *
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* *
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*************************************************************************/
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/*
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given (A,b,lo,hi), solve the LCP problem: A*x = b+w, where each x(i),w(i)
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satisfies one of
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(1) x = lo, w >= 0
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(2) x = hi, w <= 0
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(3) lo < x < hi, w = 0
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A is a matrix of dimension n*n, everything else is a vector of size n*1.
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lo and hi can be +/- dInfinity as needed. the first `nub' variables are
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unbounded, i.e. hi and lo are assumed to be +/- dInfinity.
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we restrict lo(i) <= 0 and hi(i) >= 0.
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the original data (A,b) may be modified by this function.
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if the `findex' (friction index) parameter is nonzero, it points to an array
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of index values. in this case constraints that have findex[i] >= 0 are
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special. all non-special constraints are solved for, then the lo and hi values
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for the special constraints are set:
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hi[i] = abs( hi[i] * x[findex[i]] )
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lo[i] = -hi[i]
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and the solution continues. this mechanism allows a friction approximation
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to be implemented. the first `nub' variables are assumed to have findex < 0.
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*/
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#ifndef _BT_LCP_H_
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#define _BT_LCP_H_
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#include <stdlib.h>
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#include <stdio.h>
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#include <assert.h>
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#include "LinearMath/btScalar.h"
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#include "LinearMath/btAlignedObjectArray.h"
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struct btDantzigScratchMemory
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{
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btAlignedObjectArray<btScalar> m_scratch;
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btAlignedObjectArray<btScalar> L;
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btAlignedObjectArray<btScalar> d;
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btAlignedObjectArray<btScalar> delta_w;
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btAlignedObjectArray<btScalar> delta_x;
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btAlignedObjectArray<btScalar> Dell;
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btAlignedObjectArray<btScalar> ell;
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btAlignedObjectArray<btScalar *> Arows;
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btAlignedObjectArray<int> p;
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btAlignedObjectArray<int> C;
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btAlignedObjectArray<bool> state;
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};
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//return false if solving failed
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bool btSolveDantzigLCP(int n, btScalar *A, btScalar *x, btScalar *b, btScalar *w,
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int nub, btScalar *lo, btScalar *hi, int *findex, btDantzigScratchMemory &scratch);
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#endif //_BT_LCP_H_
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