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/*
* Revision Control Information
*
* $Source$
* $Author$
* $Revision$
* $Date$
*
*/
#include "espresso.h"
static bool primes_consensus_special_cases();
static pcover primes_consensus_merge();
static pcover and_with_cofactor();
/* primes_consensus -- generate primes using consensus */
pcover primes_consensus(T)
pcube *T; /* T will be disposed of */
{
register pcube cl, cr;
register int best;
pcover Tnew, Tl, Tr;
if (primes_consensus_special_cases(T, &Tnew) == MAYBE) {
cl = new_cube();
cr = new_cube();
best = binate_split_select(T, cl, cr, COMPL);
Tl = primes_consensus(scofactor(T, cl, best));
Tr = primes_consensus(scofactor(T, cr, best));
Tnew = primes_consensus_merge(Tl, Tr, cl, cr);
free_cube(cl);
free_cube(cr);
free_cubelist(T);
}
return Tnew;
}
static bool
primes_consensus_special_cases(T, Tnew)
pcube *T; /* will be disposed if answer is determined */
pcover *Tnew; /* returned only if answer determined */
{
register pcube *T1, p, ceil, cof=T[0];
pcube last;
pcover A;
/* Check for no cubes in the cover */
if (T[2] == NULL) {
*Tnew = new_cover(0);
free_cubelist(T);
return TRUE;
}
/* Check for only a single cube in the cover */
if (T[3] == NULL) {
*Tnew = sf_addset(new_cover(1), set_or(cof, cof, T[2]));
free_cubelist(T);
return TRUE;
}
/* Check for a row of all 1's (implies function is a tautology) */
for(T1 = T+2; (p = *T1++) != NULL; ) {
if (full_row(p, cof)) {
*Tnew = sf_addset(new_cover(1), cube.fullset);
free_cubelist(T);
return TRUE;
}
}
/* Check for a column of all 0's which can be factored out */
ceil = set_save(cof);
for(T1 = T+2; (p = *T1++) != NULL; ) {
INLINEset_or(ceil, ceil, p);
}
if (! setp_equal(ceil, cube.fullset)) {
p = new_cube();
(void) set_diff(p, cube.fullset, ceil);
(void) set_or(cof, cof, p);
free_cube(p);
A = primes_consensus(T);
foreach_set(A, last, p) {
INLINEset_and(p, p, ceil);
}
*Tnew = A;
set_free(ceil);
return TRUE;
}
set_free(ceil);
/* Collect column counts, determine unate variables, etc. */
massive_count(T);
/* If single active variable not factored out above, then tautology ! */
if (cdata.vars_active == 1) {
*Tnew = sf_addset(new_cover(1), cube.fullset);
free_cubelist(T);
return TRUE;
/* Check for unate cover */
} else if (cdata.vars_unate == cdata.vars_active) {
A = cubeunlist(T);
*Tnew = sf_contain(A);
free_cubelist(T);
return TRUE;
/* Not much we can do about it */
} else {
return MAYBE;
}
}
static pcover
primes_consensus_merge(Tl, Tr, cl, cr)
pcover Tl, Tr;
pcube cl, cr;
{
register pcube pl, pr, lastl, lastr, pt;
pcover T, Tsave;
Tl = and_with_cofactor(Tl, cl);
Tr = and_with_cofactor(Tr, cr);
T = sf_new(500, Tl->sf_size);
pt = T->data;
Tsave = sf_contain(sf_join(Tl, Tr));
foreach_set(Tl, lastl, pl) {
foreach_set(Tr, lastr, pr) {
if (cdist01(pl, pr) == 1) {
consensus(pt, pl, pr);
if (++T->count >= T->capacity) {
Tsave = sf_union(Tsave, sf_contain(T));
T = sf_new(500, Tl->sf_size);
pt = T->data;
} else {
pt += T->wsize;
}
}
}
}
free_cover(Tl);
free_cover(Tr);
Tsave = sf_union(Tsave, sf_contain(T));
return Tsave;
}
static pcover
and_with_cofactor(A, cof)
pset_family A;
register pset cof;
{
register pset last, p;
foreach_set(A, last, p) {
INLINEset_and(p, p, cof);
if (cdist(p, cube.fullset) > 0) {
RESET(p, ACTIVE);
} else {
SET(p, ACTIVE);
}
}
return sf_inactive(A);
}
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