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subdivideg.c
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subdivideg.c
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/* subdivideg.c version 1.0; B D McKay, May 2011. */
#define USAGE "subdivideg [-k#] [-q] [infile [outfile]]"
#define HELPTEXT \
" Make the subdivision graphs of a file of graphs.\n\
-k# Subdivide each edge by # new vertices (default 1)\n\
\n\
The output file has a header if and only if the input file does.\n\
\n\
-q Suppress auxiliary information.\n"
/*************************************************************************/
#include "gtools.h"
/**************************************************************************/
static void
subdivisiongraph(sparsegraph *g, int k, sparsegraph *h)
/* h := subdivision graph of g, k new vertices per edge */
{
DYNALLSTAT(size_t,eno,eno_sz); /* edge number */
int *ge,*gd,*he,*hd;
size_t *gv,*hv;
int gnv,hnv;
size_t i,j,l,gnde,hnde,num;
size_t hi,lo,mid,w;
if (k == 0)
{
copy_sg(g,h);
return;
}
sortlists_sg(g);
SG_VDE(g,gv,gd,ge);
gnv = g->nv;
gnde = g->nde;
DYNALLOC1(size_t,eno,eno_sz,gnde,"subdivideg");
hnv = gnv + k*(gnde/2);
if (hnv <= 0 || (gnde > 0 && ((size_t)(hnv-gnv))/(gnde/2) != k))
gt_abort(">E subdivideg: output graph too large\n");
hnde = gnde * (k+1);
if (hnde/(k+1) != gnde)
gt_abort(">E subdivideg: output graph too large\n");
num = 0;
for (i = 0; i < gnv; ++i)
{
for (j = gv[i]; j < gv[i]+gd[i]; ++j)
{
if (ge[j] == i)
gt_abort(">E subdivideg can't handle undirected loops\n");
else if (ge[j] > i)
eno[j] = num++;
else
{
lo = gv[ge[j]];
hi = lo + gd[ge[j]] - 1;
while (lo <= hi)
{
mid = lo + (hi-lo)/2;
if (ge[mid] == i) break;
else if (ge[mid] < i) lo = mid+1;
else hi = mid-1;
}
if (lo > hi)
gt_abort(">E subdivideg : binary search failed\n");
eno[j] = eno[mid];
}
}
}
SG_ALLOC(*h,hnv,hnde,"subdivideg");
h->nv = hnv;
h->nde = hnde;
SG_VDE(h,hv,hd,he);
for (i = 0; i < gnv; ++i)
{
hd[i] = gd[i];
hv[i] = gv[i];
}
for (i = gnv; i < hnv; ++i)
{
hd[i] = 2;
hv[i] = gnde + 2*(i-gnv);
}
for (i = 0; i < gnv; ++i)
{
for (j = gv[i]; j < gv[i]+gd[i]; ++j)
if (ge[j] > i)
{
w = gnv + k*eno[j];
he[j] = w;
he[hv[w]] = i;
for (l = 1; l < k; ++l)
{
he[hv[w]+1] = w+1;
he[hv[w+1]] = w;
++w;
}
}
else
{
w = gnv + k*eno[j] + k - 1;
he[j] = w;
he[hv[w]+1] = i;
}
}
}
/**************************************************************************/
int
main(int argc, char *argv[])
{
char *infilename,*outfilename;
FILE *infile,*outfile;
boolean badargs,quiet,kswitch;
int j,argnum,kvalue;
int codetype,outcode;
SG_DECL(g); SG_DECL(h);
nauty_counter nin;
char *arg,sw;
double t;
HELP; PUTVERSION;
infilename = outfilename = NULL;
quiet = kswitch = FALSE;
kvalue = 1;
argnum = 0;
badargs = FALSE;
for (j = 1; !badargs && j < argc; ++j)
{
arg = argv[j];
if (arg[0] == '-' && arg[1] != '\0')
{
++arg;
while (*arg != '\0')
{
sw = *arg++;
SWBOOLEAN('q',quiet)
else SWINT('k',kswitch,kvalue,"subdivideg -k")
else badargs = TRUE;
}
}
else
{
++argnum;
if (argnum == 1) infilename = arg;
else if (argnum == 2) outfilename = arg;
else badargs = TRUE;
}
}
if (badargs)
{
fprintf(stderr,">E Usage: %s\n",USAGE);
GETHELP;
exit(1);
}
if (!quiet)
{
fprintf(stderr,">A subdivideg");
if (kswitch) fprintf(stderr," -k%d",kvalue);
if (argnum > 0) fprintf(stderr," %s",infilename);
if (argnum > 1) fprintf(stderr," %s",outfilename);
fprintf(stderr,"\n");
fflush(stderr);
}
if (infilename && infilename[0] == '-') infilename = NULL;
infile = opengraphfile(infilename,&codetype,FALSE,1);
if (!infile) exit(1);
if (!infilename) infilename = "stdin";
NODIGRAPHSYET(codetype);
if (!outfilename || outfilename[0] == '-')
{
outfilename = "stdout";
outfile = stdout;
}
else if ((outfile = fopen(outfilename,"w")) == NULL)
{
fprintf(stderr,"Can't open output file %s\n",outfilename);
gt_abort(NULL);
}
if (codetype&SPARSE6) outcode = SPARSE6;
else outcode = GRAPH6;
if (codetype&HAS_HEADER)
{
if (outcode == SPARSE6) writeline(outfile,SPARSE6_HEADER);
else writeline(outfile,GRAPH6_HEADER);
}
nin = 0;
t = CPUTIME;
while (read_sg(infile,&g))
{
++nin;
subdivisiongraph(&g,kvalue,&h);
if (outcode == SPARSE6) writes6_sg(outfile,&h);
else writeg6_sg(outfile,&h);
}
t = CPUTIME - t;
if (!quiet)
{
fprintf(stderr,">Z " COUNTER_FMT
" graphs converted from %s to %s in %3.2f sec.\n",
nin,infilename,outfilename,t);
}
exit(0);
}

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