1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/* $Id: db_bundle.h,v 1.2 2011/06/17 14:03:30 mbansal Exp $ */
18
19#ifndef DB_BUNDLE_H
20#define DB_BUNDLE_H
21
22
23/*****************************************************************
24*    Lean and mean begins here                                   *
25*****************************************************************/
26/*!
27 * \defgroup LMBundle (LM) Bundle adjustment utilities (a.k.a. Levenberg-Marquardt algorithm)
28 */
29/*\{*/
30
31#include "db_utilities.h"
32
33/*!
34Solve for update dx such that diagmult(1+lambda,transpose(J)%J)%dx= -Jtf
35using only upper half of JtJ, destroying lower half below diagonal in the process
36dimension is n and d should point to n allocated doubles of scratch memory
37*/
38inline void db_Compute_dx(double *dx,double **JtJ,double *min_Jtf,double lambda,double *d,int n)
39{
40    int i;
41    double opl;
42
43    opl=1.0+lambda;
44    for(i=0;i<n;i++) d[i]=JtJ[i][i]*opl;
45
46    db_CholeskyDecompSeparateDiagonal(JtJ,d,n);
47    db_CholeskyBacksub(dx,JtJ,d,n,min_Jtf);
48}
49
50/*!
51Solve for update dx such that diagmult(1+lambda,transpose(J)%J)%dx= -Jtf
52using only upper half of JtJ, destroying lower half below diagonal in the process
53*/
54inline void db_Compute_dx_3x3(double dx[3],double JtJ[9],const double min_Jtf[3],double lambda)
55{
56    double d[3],opl;
57
58    opl=1.0+lambda;
59    d[0]=JtJ[0]*opl;
60    d[1]=JtJ[4]*opl;
61    d[2]=JtJ[8]*opl;
62    db_CholeskyDecomp3x3SeparateDiagonal(JtJ,d);
63    db_CholeskyBacksub3x3(dx,JtJ,d,min_Jtf);
64}
65
66/*\}*/
67
68#endif /* DB_BUNDLE_H */
69