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 /*!
34 Solve for update dx such that diagmult(1+lambda,transpose(J)%J)%dx= -Jtf
35 using only upper half of JtJ, destroying lower half below diagonal in the process
36 dimension is n and d should point to n allocated doubles of scratch memory
37 */
db_Compute_dx(double * dx,double ** JtJ,double * min_Jtf,double lambda,double * d,int n)38 inline 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 /*!
51 Solve for update dx such that diagmult(1+lambda,transpose(J)%J)%dx= -Jtf
52 using only upper half of JtJ, destroying lower half below diagonal in the process
53 */
db_Compute_dx_3x3(double dx[3],double JtJ[9],const double min_Jtf[3],double lambda)54 inline 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