/*************************************************************************
* This function perfoms a dfs starting from an unmatched col node
* forming alternate paths
**************************************************************************/
void MinCover_RowDFS(idxtype *xadj, idxtype *adjncy, int root, idxtype *mate, idxtype *where, int flag)
{
int i;
if (flag == INROW) {
if (where[root] == VR)
return;
where[root] = VR;
for (i=xadj[root]; i<xadj[root+1]; i++)
MinCover_RowDFS(xadj, adjncy, adjncy[i], mate, where, INCOL);
}
else {
if (where[root] == VC)
return;
where[root] = VC;
if (mate[root] != -1)
MinCover_RowDFS(xadj, adjncy, mate[root], mate, where, INROW);
}
}
/*************************************************************************
* This function perfoms a dfs starting from an unmatched col node
* forming alternate paths
**************************************************************************/
void MinCover_RowDFS(idx_t *xadj, idx_t *adjncy, idx_t root, idx_t *mate, idx_t *where, idx_t flag) {
idx_t i;
if (flag == INROW) {
if (where[root] == VR) {
return;
}
where[root] = VR;
for (i = xadj[root]; i < xadj[root + 1]; i++) {
MinCover_RowDFS(xadj, adjncy, adjncy[i], mate, where, INCOL);
}
} else {
if (where[root] == VC) {
return;
}
where[root] = VC;
if (mate[root] != -1) {
MinCover_RowDFS(xadj, adjncy, mate[root], mate, where, INROW);
}
}
}
/*************************************************************************
* This function performs a coarse decomposition and determines the
* min-cover.
* REF: Pothen ACMTrans. on Amth Software
**************************************************************************/
void MinCover_Decompose(idxtype *xadj, idxtype *adjncy, int asize, int bsize, idxtype *mate, idxtype *cover, int *csize)
{
int i, k;
idxtype *where;
int card[10];
where = idxmalloc(bsize, "MinCover_Decompose: where");
for (i=0; i<10; i++)
card[i] = 0;
for (i=0; i<asize; i++)
where[i] = SC;
for (; i<bsize; i++)
where[i] = SR;
for (i=0; i<asize; i++)
if (mate[i] == -1)
MinCover_ColDFS(xadj, adjncy, i, mate, where, INCOL);
for (; i<bsize; i++)
if (mate[i] == -1)
MinCover_RowDFS(xadj, adjncy, i, mate, where, INROW);
for (i=0; i<bsize; i++)
card[where[i]]++;
k = 0;
if (abs(card[VC]+card[SC]-card[HR]) < abs(card[VC]-card[SR]-card[HR])) { /* S = VC+SC+HR */
/* printf("%d %d ",vc+sc, hr); */
for (i=0; i<bsize; i++)
if (where[i] == VC || where[i] == SC || where[i] == HR)
cover[k++] = i;
}
else { /* S = VC+SR+HR */
/* printf("%d %d ",vc, hr+sr); */
for (i=0; i<bsize; i++)
if (where[i] == VC || where[i] == SR || where[i] == HR)
cover[k++] = i;
}
*csize = k;
free(where);
}
/*************************************************************************
* This function performs a coarse decomposition and determines the
* min-cover.
* REF: Pothen ACMTrans. on Amth Software
**************************************************************************/
void MinCover_Decompose(idx_t *xadj, idx_t *adjncy, idx_t asize, idx_t bsize, idx_t *mate, idx_t *cover, idx_t *csize) {
idx_t i, k;
idx_t *where;
idx_t card[10];
where = imalloc(bsize, "MinCover_Decompose: where");
for (i = 0; i < 10; i++) {
card[i] = 0;
}
for (i = 0; i < asize; i++) {
where[i] = SC;
}
for (; i < bsize; i++) {
where[i] = SR;
}
for (i = 0; i < asize; i++) {
if (mate[i] == -1) {
MinCover_ColDFS(xadj, adjncy, i, mate, where, INCOL);
}
}
for (; i < bsize; i++) {
if (mate[i] == -1) {
MinCover_RowDFS(xadj, adjncy, i, mate, where, INROW);
}
}
for (i = 0; i < bsize; i++) {
card[where[i]]++;
}
k = 0;
if (iabs(card[VC] + card[SC] - card[HR]) < iabs(card[VC] - card[SR] - card[HR])) { /* S = VC+SC+HR */
/* printf("%"PRIDX" %"PRIDX" ",vc+sc, hr); */
for (i = 0; i < bsize; i++) {
if (where[i] == VC || where[i] == SC || where[i] == HR) {
cover[k++] = i;
}
}
} else { /* S = VC+SR+HR */
/* printf("%"PRIDX" %"PRIDX" ",vc, hr+sr); */
for (i = 0; i < bsize; i++) {
if (where[i] == VC || where[i] == SR || where[i] == HR) {
cover[k++] = i;
}
}
}
*csize = k;
gk_free((void **) &where, LTERM);
}
