| 1 |
jgs |
150 |
/* $Id$ */ |
| 2 |
|
|
|
| 3 |
|
|
/**********************************************************************/ |
| 4 |
|
|
|
| 5 |
|
|
/* Paso: SystemMatrixPattern: Paso_SystemMatrixPattern_mis |
| 6 |
|
|
|
| 7 |
|
|
searches for a maximal independent set MIS in the matrix pattern |
| 8 |
|
|
vertices in the maximal independent set are marked in mis_marker |
| 9 |
|
|
|
| 10 |
|
|
*/ |
| 11 |
|
|
/**********************************************************************/ |
| 12 |
|
|
|
| 13 |
|
|
/* Copyrights by ACcESS Australia 2003,2004,2005 */ |
| 14 |
|
|
/* Author: gross@access.edu.au */ |
| 15 |
|
|
|
| 16 |
|
|
/**************************************************************/ |
| 17 |
|
|
|
| 18 |
|
|
#include "Paso.h" |
| 19 |
|
|
#include "Util.h" |
| 20 |
|
|
#include "SystemMatrixPattern.h" |
| 21 |
|
|
|
| 22 |
|
|
|
| 23 |
|
|
/* used to generate pseudo random numbers: */ |
| 24 |
|
|
|
| 25 |
|
|
static double Paso_SystemMatrixPattern_mis_seed=.4142135623730951; |
| 26 |
|
|
|
| 27 |
|
|
|
| 28 |
|
|
/***************************************************************/ |
| 29 |
|
|
|
| 30 |
|
|
#define IS_AVAILABLE -1 |
| 31 |
|
|
#define IS_IN_MIS_NOW -2 |
| 32 |
|
|
#define IS_IN_MIS -3 |
| 33 |
|
|
#define IS_CONNECTED_TO_MIS -4 |
| 34 |
|
|
|
| 35 |
|
|
void Paso_SystemMatrixPattern_mis(Paso_SystemMatrixPattern* pattern_p, index_t* mis_marker) { |
| 36 |
|
|
|
| 37 |
|
|
dim_t i; |
| 38 |
|
|
index_t naib,iptr; |
| 39 |
|
|
bool_t flag; |
| 40 |
|
|
dim_t n=pattern_p->n_ptr; |
| 41 |
|
|
double *value=TMPMEMALLOC(n,double); |
| 42 |
|
|
if (!Paso_checkPtr(value)) { |
| 43 |
|
|
#pragma omp parallel for private(i) schedule(static) |
| 44 |
|
|
for (i=0;i<n;++i) mis_marker[i]=IS_AVAILABLE; |
| 45 |
|
|
|
| 46 |
|
|
/* is there any vertex available ?*/ |
| 47 |
|
|
while (Paso_Util_isAny(n,mis_marker,IS_AVAILABLE)) { |
| 48 |
|
|
/* step 1: assign a random number in [0,1] to each vertex */ |
| 49 |
|
|
/* step 2: is the vertex is available, check if its value is the smaller than all values of its naigbours |
| 50 |
|
|
if the answer is yes, the vertex is put into the independend set and all |
| 51 |
|
|
its naighbours are removed from the graph by setting it mis_marker to FALSE */ |
| 52 |
|
|
|
| 53 |
|
|
/* step 2: is the vertex is available, check if its value is the smaller than all values of its naigbours */ |
| 54 |
|
|
|
| 55 |
|
|
/* assign random number in [0,1] to each vertex */ |
| 56 |
|
|
#pragma omp parallel for private(i) schedule(static) |
| 57 |
|
|
for (i=0;i<n;++i) { |
| 58 |
|
|
if (mis_marker[i]==IS_AVAILABLE) { |
| 59 |
|
|
value[i]=fmod(Paso_SystemMatrixPattern_mis_seed*(i+1),1.); |
| 60 |
|
|
} else { |
| 61 |
|
|
value[i]=2.; |
| 62 |
|
|
} |
| 63 |
|
|
} |
| 64 |
|
|
/* update the seed */ |
| 65 |
jgs |
154 |
/* Paso_SystemMatrixPattern_mis_seed=fmod(sqrt(Paso_SystemMatrixPattern_mis_seed*(n+1)),1.); */ |
| 66 |
jgs |
150 |
/* detect independent vertices as those vertices that have a value less than all values of its naigbours */ |
| 67 |
|
|
#pragma omp parallel for private(naib,i,iptr,flag) schedule(static) |
| 68 |
|
|
for (i=0;i<n;++i) { |
| 69 |
|
|
if (mis_marker[i]==IS_AVAILABLE) { |
| 70 |
|
|
flag=IS_IN_MIS_NOW; |
| 71 |
|
|
for (iptr=pattern_p->ptr[i];iptr<pattern_p->ptr[i+1]; ++iptr) { |
| 72 |
|
|
naib=pattern_p->index[iptr]; |
| 73 |
|
|
if (naib!=i && value[naib]<=value[i]) { |
| 74 |
|
|
flag=IS_AVAILABLE; |
| 75 |
|
|
break; |
| 76 |
|
|
} |
| 77 |
|
|
} |
| 78 |
|
|
mis_marker[i]=flag; |
| 79 |
|
|
} |
| 80 |
|
|
} |
| 81 |
|
|
/* detect independent vertices as those vertices that have a value less than all values of its naigbours */ |
| 82 |
|
|
#pragma omp parallel for private(naib,i,iptr) schedule(static) |
| 83 |
|
|
for (i=0;i<n;i++) { |
| 84 |
|
|
if (mis_marker[i]==IS_IN_MIS_NOW) { |
| 85 |
|
|
for (iptr=pattern_p->ptr[i];iptr<pattern_p->ptr[i+1]; ++iptr) { |
| 86 |
|
|
naib=pattern_p->index[iptr]; |
| 87 |
|
|
if (naib!=i) mis_marker[naib]=IS_CONNECTED_TO_MIS; |
| 88 |
|
|
} |
| 89 |
|
|
mis_marker[i]=IS_IN_MIS; |
| 90 |
|
|
} |
| 91 |
|
|
} |
| 92 |
|
|
} |
| 93 |
|
|
/* swap to TRUE/FALSE in mis_marker */ |
| 94 |
|
|
#pragma omp parallel for private(i) schedule(static) |
| 95 |
|
|
for (i=0;i<n;i++) mis_marker[i]=(mis_marker[i]==IS_IN_MIS); |
| 96 |
|
|
} |
| 97 |
|
|
TMPMEMFREE(value); |
| 98 |
|
|
} |
| 99 |
|
|
#undef IS_AVAILABLE |
| 100 |
|
|
#undef IS_IN_MIS_NOW |
| 101 |
|
|
#undef IS_IN_MIS |
| 102 |
|
|
#undef IS_CONNECTED_TO_MIS |
Parent Directory
| 
Revision Log