/[escript]/trunk/paso/src/Pattern_mis.c
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Annotation of /trunk/paso/src/Pattern_mis.c

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Revision 2107 - (hide annotations)
Fri Nov 28 04:39:07 2008 UTC (10 years, 10 months ago) by artak
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Current version of AMG uses ILU for relaxation, however it is not stable when schur matrix becames more denser. For example it is not stable for -e paramenter is more 400 in 2D for convection problem 
1 ksteube 1315
2     /*******************************************************
3 ksteube 1811 *
4     * Copyright (c) 2003-2008 by University of Queensland
5     * Earth Systems Science Computational Center (ESSCC)
6     * http://www.uq.edu.au/esscc
7     *
8     * Primary Business: Queensland, Australia
9     * Licensed under the Open Software License version 3.0
10     * http://www.opensource.org/licenses/osl-3.0.php
11     *
12     *******************************************************/
13 ksteube 1315
14 ksteube 1811
15 ksteube 1315 /**********************************************************************/
16    
17     /* Paso: Pattern: Paso_Pattern_mis
18    
19     searches for a maximal independent set MIS in the matrix pattern
20     vertices in the maximal independent set are marked in mis_marker
21     nodes to be considered are marked by -1 on the input in mis_marker
22    
23     */
24     /**********************************************************************/
25    
26     /* Copyrights by ACcESS Australia 2003,2004,2005 */
27     /* Author: gross@access.edu.au */
28    
29     /**************************************************************/
30    
31     #include "mpi_C.h"
32     #include "Paso.h"
33     #include "PasoUtil.h"
34     #include "Pattern.h"
35    
36    
37     /* used to generate pseudo random numbers: */
38    
39     static double Paso_Pattern_mis_seed=.4142135623730951;
40    
41    
42     /***************************************************************/
43    
44     #define IS_AVAILABLE -1
45     #define IS_IN_MIS_NOW -2
46     #define IS_IN_MIS -3
47     #define IS_CONNECTED_TO_MIS -4
48    
49     void Paso_Pattern_mis(Paso_Pattern* pattern_p, index_t* mis_marker) {
50    
51     index_t index_offset=(pattern_p->type & PATTERN_FORMAT_OFFSET1 ? 1:0);
52     dim_t i;
53     double *value;
54     index_t naib,iptr;
55     bool_t flag;
56     dim_t n=pattern_p->numOutput;
57     if (pattern_p->type & PATTERN_FORMAT_SYM) {
58     Paso_setError(TYPE_ERROR,"Paso_Pattern_mis: symmetric matrix pattern is not supported yet");
59     return;
60     }
61     value=TMPMEMALLOC(n,double);
62     if (!Paso_checkPtr(value)) {
63    
64    
65     /* is there any vertex available ?*/
66     while (Paso_Util_isAny(n,mis_marker,IS_AVAILABLE)) {
67     /* step 1: assign a random number in [0,1] to each vertex */
68     /* step 2: is the vertex is available, check if its value is the smaller than all values of its naigbours
69     if the answer is yes, the vertex is put into the independend set and all
70     its naighbours are removed from the graph by setting it mis_marker to FALSE */
71    
72     /* step 2: is the vertex is available, check if its value is the smaller than all values of its naigbours */
73    
74     /* assign random number in [0,1] to each vertex */
75     #pragma omp parallel for private(i) schedule(static)
76     for (i=0;i<n;++i) {
77     if (mis_marker[i]==IS_AVAILABLE) {
78     value[i]=fmod(Paso_Pattern_mis_seed*(i+1),1.);
79     } else {
80     value[i]=2.;
81     }
82     }
83     /* update the seed */
84     /* Paso_Pattern_mis_seed=fmod(sqrt(Paso_Pattern_mis_seed*(n+1)),1.); */
85     /* detect independent vertices as those vertices that have a value less than all values of its naigbours */
86     #pragma omp parallel for private(naib,i,iptr,flag) schedule(static)
87     for (i=0;i<n;++i) {
88     if (mis_marker[i]==IS_AVAILABLE) {
89     flag=IS_IN_MIS_NOW;
90     for (iptr=pattern_p->ptr[i]-index_offset;iptr<pattern_p->ptr[i+1]-index_offset; ++iptr) {
91     naib=pattern_p->index[iptr]-index_offset;
92     if (naib!=i && value[naib]<=value[i]) {
93     flag=IS_AVAILABLE;
94     break;
95     }
96     }
97     mis_marker[i]=flag;
98     }
99     }
100     /* detect independent vertices as those vertices that have a value less than all values of its naigbours */
101     #pragma omp parallel for private(naib,i,iptr) schedule(static)
102     for (i=0;i<n;i++) {
103     if (mis_marker[i]==IS_IN_MIS_NOW) {
104     for (iptr=pattern_p->ptr[i]-index_offset;iptr<pattern_p->ptr[i+1]-index_offset; ++iptr) {
105     naib=pattern_p->index[iptr]-index_offset;
106     if (naib!=i) mis_marker[naib]=IS_CONNECTED_TO_MIS;
107     }
108     mis_marker[i]=IS_IN_MIS;
109     }
110     }
111     }
112     /* swap to TRUE/FALSE in mis_marker */
113     #pragma omp parallel for private(i) schedule(static)
114     for (i=0;i<n;i++) mis_marker[i]=(mis_marker[i]==IS_IN_MIS);
115     }
116     TMPMEMFREE(value);
117     }
118     #undef IS_AVAILABLE
119     #undef IS_IN_MIS_NOW
120     #undef IS_IN_MIS
121     #undef IS_CONNECTED_TO_MIS
122 gross 1361
123     void Paso_Pattern_color(Paso_Pattern* pattern, index_t* num_colors, index_t* colorOf) {
124     index_t out=0, *mis_marker=NULL,i;
125     dim_t n=pattern->numOutput;
126     mis_marker=TMPMEMALLOC(n,index_t);
127     if ( !Paso_checkPtr(mis_marker) ) {
128     /* get coloring */
129     #pragma omp parallel for private(i) schedule(static)
130 artak 2107 for (i = 0; i < n; ++i) {
131     colorOf[i]=-1;
132     mis_marker[i]=-1;
133     }
134 gross 1361
135     while (Paso_Util_isAny(n,colorOf,-1) && Paso_noError()) {
136 artak 2107 /*#pragma omp parallel for private(i) schedule(static)
137     for (i = 0; i < n; ++i) mis_marker[i]=colorOf[i];*/
138 gross 1361 Paso_Pattern_mis(pattern,mis_marker);
139    
140     #pragma omp parallel for private(i) schedule(static)
141 artak 2107 for (i = 0; i < n; ++i) {
142     if (mis_marker[i]) colorOf[i]=out;
143     mis_marker[i]=colorOf[i];
144     }
145 gross 1361 ++out;
146     }
147     TMPMEMFREE(mis_marker);
148     *num_colors=out;
149     }
150     }

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