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offset.h
1 //
2 // offset.h
3 //
4 // Copyright (C) 1996 Limit Point Systems, Inc.
5 //
6 // Author: Curtis Janssen <cljanss@ca.sandia.gov>
7 // Maintainer: LPS
8 //
9 // This file is part of the SC Toolkit.
10 //
11 // The SC Toolkit is free software; you can redistribute it and/or modify
12 // it under the terms of the GNU Library General Public License as published by
13 // the Free Software Foundation; either version 2, or (at your option)
14 // any later version.
15 //
16 // The SC Toolkit is distributed in the hope that it will be useful,
17 // but WITHOUT ANY WARRANTY; without even the implied warranty of
18 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 // GNU Library General Public License for more details.
20 //
21 // You should have received a copy of the GNU Library General Public License
22 // along with the SC Toolkit; see the file COPYING.LIB. If not, write to
23 // the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
24 //
25 // The U.S. Government is granted a limited license as per AL 91-7.
26 //
27
28 #ifndef _math_scmat_offset_h
29 #define _math_scmat_offset_h
30
31 #ifdef __c_plus_plus
32
33 namespace sc {
34
35 static inline int
36 i_offset(int i)
37 {
38 return ((i*(i+1)) >> 1);
39 }
40
41 static inline int
42 ij_offset(int i, int j)
43 {
44 return (i>j) ? (((i*(i+1)) >> 1) + j) : (((j*(j+1)) >> 1) + i);
45 }
46
47 static inline int
48 igtj_offset(int i, int j)
49 {
50 return ((i*(i+1)) >> 1) + j;
51 }
52
53 }
54
55 #else
56
57 #define i_offset(i) (((i)*((i)+1))>>1)
58 #define ij_offset(i,j) (((i)>(j))?(i_offset(i)+(j)):(i_offset(j)+(i)))
59 #define igtj_offset(i,j) (i_offset(i)+(j))
60
61 #endif
62
63 #endif