ref: f279c5eba035d018a8805a65a8a245b8b8d2ea2e
dir: /auxiliary/matching.c/
/*
* Standalone tool to run the matching algorithm.
*/
#include <assert.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include "puzzles.h"
#include "matching.h"
#include "tree234.h"
static int nl, nr, count;
static int **adjlists, *adjsizes;
static int *adjdata, *outl, *outr, *witness;
static void *scratch;
static random_state *rs;
static void allocate(int nl_, int nr_, int maxedges)
{
nl = nl_;
nr = nr_;
adjdata = snewn(maxedges, int);
adjlists = snewn(nl, int *);
adjsizes = snewn(nl, int);
outl = snewn(nl, int);
outr = snewn(nr, int);
witness = snewn(nl+nr, int);
scratch = smalloc(matching_scratch_size(nl, nr));
}
static void deallocate(void)
{
sfree(adjlists);
sfree(adjsizes);
sfree(adjdata);
sfree(outl);
sfree(outr);
sfree(witness);
sfree(scratch);
}
static void find_and_check_matching(void)
{
int i, j, k;
count = matching_with_scratch(scratch, nl, nr, adjlists, adjsizes,
rs, outl, outr);
matching_witness(scratch, nl, nr, witness);
for (i = j = 0; i < nl; i++) {
if (outl[i] != -1) {
assert(0 <= outl[i] && outl[i] < nr);
assert(outr[outl[i]] == i);
j++;
for (k = 0; k < adjsizes[i]; k++)
if (adjlists[i][k] == outl[i])
break;
assert(k < adjsizes[i]);
}
}
assert(j == count);
for (i = j = 0; i < nr; i++) {
if (outr[i] != -1) {
assert(0 <= outr[i] && outr[i] < nl);
assert(outl[outr[i]] == i);
j++;
}
}
assert(j == count);
for (i = 0; i < nl; i++) {
if (outl[i] == -1)
assert(witness[i] == 0);
}
for (i = 0; i < nr; i++) {
if (outr[i] == -1)
assert(witness[nl+i] == 1);
}
for (i = 0; i < nl; i++) {
for (j = 0; j < adjsizes[i]; j++) {
k = adjlists[i][j];
if (outl[i] == k)
assert(!(witness[i] == 1 && witness[nl+k] == 0));
else
assert(!(witness[i] == 0 && witness[nl+k] == 1));
}
}
}
struct nodename {
const char *name;
int index;
};
static int compare_nodes(void *av, void *bv)
{
const struct nodename *a = (const struct nodename *)av;
const struct nodename *b = (const struct nodename *)bv;
return strcmp(a->name, b->name);
}
static int node_index(tree234 *n2i, tree234 *i2n, const char *name)
{
struct nodename *nn, *nn_prev;
char *namedup = dupstr(name);
nn = snew(struct nodename);
nn->name = namedup;
nn->index = count234(n2i);
nn_prev = add234(n2i, nn);
if (nn_prev != nn) {
sfree(nn);
sfree(namedup);
} else {
addpos234(i2n, nn, nn->index);
}
return nn_prev->index;
}
struct edge {
int L, R;
};
static int compare_edges(void *av, void *bv)
{
const struct edge *a = (const struct edge *)av;
const struct edge *b = (const struct edge *)bv;
if (a->L < b->L) return -1;
if (a->L > b->L) return +1;
if (a->R < b->R) return -1;
if (a->R > b->R) return +1;
return 0;
}
static void matching_from_user_input(FILE *fp, const char *filename)
{
tree234 *Ln2i, *Li2n, *Rn2i, *Ri2n, *edges;
char *line = NULL;
struct edge *e;
int i, lineno = 0;
int *adjptr;
Ln2i = newtree234(compare_nodes);
Rn2i = newtree234(compare_nodes);
Li2n = newtree234(NULL);
Ri2n = newtree234(NULL);
edges = newtree234(compare_edges);
while (sfree(line), lineno++, (line = fgetline(fp)) != NULL) {
char *p, *Lname, *Rname;
p = line;
while (*p && isspace((unsigned char)*p)) p++;
if (!*p)
continue;
Lname = p;
while (*p && !isspace((unsigned char)*p)) p++;
if (*p)
*p++ = '\0';
while (*p && isspace((unsigned char)*p)) p++;
if (!*p) {
fprintf(stderr, "%s:%d: expected 2 words, found 1\n",
filename, lineno);
exit(1);
}
Rname = p;
while (*p && !isspace((unsigned char)*p)) p++;
if (*p)
*p++ = '\0';
while (*p && isspace((unsigned char)*p)) p++;
if (*p) {
fprintf(stderr, "%s:%d: expected 2 words, found more\n",
filename, lineno);
exit(1);
}
e = snew(struct edge);
e->L = node_index(Ln2i, Li2n, Lname);
e->R = node_index(Rn2i, Ri2n, Rname);
if (add234(edges, e) != e) {
fprintf(stderr, "%s:%d: duplicate edge\n",
filename, lineno);
exit(1);
}
}
allocate(count234(Ln2i), count234(Rn2i), count234(edges));
adjptr = adjdata;
for (i = 0; i < nl; i++)
adjlists[i] = NULL;
for (i = 0; (e = index234(edges, i)) != NULL; i++) {
if (!adjlists[e->L])
adjlists[e->L] = adjptr;
*adjptr++ = e->R;
adjsizes[e->L] = adjptr - adjlists[e->L];
}
find_and_check_matching();
for (i = 0; i < nl; i++) {
if (outl[i] != -1) {
struct nodename *Lnn = index234(Li2n, i);
struct nodename *Rnn = index234(Ri2n, outl[i]);
printf("%s %s\n", Lnn->name, Rnn->name);
}
}
deallocate();
}
static void test_subsets(void)
{
int b = 8;
int n = 1 << b;
int i, j, nruns, expected_size;
int *adjptr;
int *edgecounts;
struct stats {
int min, max;
double n, sx, sxx;
} *stats;
static const char seed[] = "fixed random seed for repeatability";
/*
* Generate a graph in which every subset of [b] = {1,...,b}
* (represented as a b-bit integer 0 <= i < n) has an edge going
* to every subset obtained by removing exactly one element.
*
* This graph is the disjoint union of the corresponding graph for
* each layer (collection of same-sized subset) of the power set
* of [b]. Each of those graphs has a matching of size equal to
* the smaller of its vertex sets. So we expect the overall size
* of the output matching to be less than n by the size of the
* largest layer, that is, to be n - binomial(n, floor(n/2)).
*
* We run the generation repeatedly, randomising it every time,
* and we expect to see every possible edge appear sooner or
* later.
*/
rs = random_new(seed, strlen(seed));
allocate(n, n, n*b);
adjptr = adjdata;
expected_size = 0;
for (i = 0; i < n; i++) {
adjlists[i] = adjptr;
for (j = 0; j < b; j++) {
if (i & (1 << j))
*adjptr++ = i & ~(1 << j);
}
adjsizes[i] = adjptr - adjlists[i];
if (adjsizes[i] != b/2)
expected_size++;
}
edgecounts = snewn(n*b, int);
for (i = 0; i < n*b; i++)
edgecounts[i] = 0;
stats = snewn(b, struct stats);
nruns = 0;
while (nruns < 10000) {
nruns++;
find_and_check_matching();
assert(count == expected_size);
for (i = 0; i < n; i++)
for (j = 0; j < b; j++)
if ((i ^ outl[i]) == (1 << j))
edgecounts[b*i+j]++;
if (nruns % 1000 == 0) {
for (i = 0; i < b; i++) {
struct stats *st = &stats[i];
st->min = st->max = -1;
st->n = st->sx = st->sxx = 0;
}
for (i = 0; i < n; i++) {
int pop = 0;
for (j = 0; j < b; j++)
if (i & (1 << j))
pop++;
pop--;
for (j = 0; j < b; j++) {
if (i & (1 << j)) {
struct stats *st = &stats[pop];
int x = edgecounts[b*i+j];
if (st->max == -1 || st->max < x)
st->max = x;
if (st->min == -1 || st->min > x)
st->min = x;
st->n++;
st->sx += x;
st->sxx += (double)x*x;
} else {
assert(edgecounts[b*i+j] == 0);
}
}
}
}
}
printf("after %d runs:\n", nruns);
for (j = 0; j < b; j++) {
struct stats *st = &stats[j];
printf("edges between layers %d,%d:"
" min=%d max=%d mean=%f variance=%f\n",
j, j+1, st->min, st->max, st->sx/st->n,
(st->sxx - st->sx*st->sx/st->n) / st->n);
}
sfree(edgecounts);
deallocate();
}
int main(int argc, char **argv)
{
static const char stdin_identifier[] = "<standard input>";
const char *infile = NULL;
bool doing_opts = true;
enum { USER_INPUT, AUTOTEST } mode = USER_INPUT;
while (--argc > 0) {
const char *arg = *++argv;
if (doing_opts && arg[0] == '-' && arg[1]) {
if (!strcmp(arg, "--")) {
doing_opts = false;
} else if (!strcmp(arg, "--random")) {
char buf[64];
int len = sprintf(buf, "%lu", (unsigned long)time(NULL));
rs = random_new(buf, len);
} else if (!strcmp(arg, "--autotest")) {
mode = AUTOTEST;
} else {
fprintf(stderr, "matching: unrecognised option '%s'\n", arg);
return 1;
}
} else {
if (!infile) {
infile = (!strcmp(arg, "-") ? stdin_identifier : arg);
} else {
fprintf(stderr, "matching: too many arguments\n");
return 1;
}
}
}
if (mode == USER_INPUT) {
FILE *fp;
if (!infile)
infile = stdin_identifier;
if (infile != stdin_identifier) {
fp = fopen(infile, "r");
if (!fp) {
fprintf(stderr, "matching: could not open input file '%s'\n",
infile);
return 1;
}
} else {
fp = stdin;
}
matching_from_user_input(fp, infile);
if (infile != stdin_identifier)
fclose(fp);
}
if (mode == AUTOTEST) {
if (infile) {
fprintf(stderr, "matching: expected no filename argument "
"with --autotest\n");
return 1;
}
test_subsets();
}
return 0;
}