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/**
@file
@ingroup cudd
@brief Functions for symmetry-based %ZDD variable reordering.
@see cuddSymmetry.c
@author Hyong-Kyoon Shin, In-Ho Moon
@copyright@parblock
Copyright (c) 1995-2015, Regents of the University of Colorado
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
Neither the name of the University of Colorado nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
@endparblock
*/
#include "util.h"
#include "cuddInt.h"
/*---------------------------------------------------------------------------*/
/* Constant declarations */
/*---------------------------------------------------------------------------*/
#define ZDD_MV_OOM (Move *)1
/*---------------------------------------------------------------------------*/
/* Stucture declarations */
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
/* Type declarations */
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
/* Variable declarations */
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
/* Macro declarations */
/*---------------------------------------------------------------------------*/
/** \cond */
/*---------------------------------------------------------------------------*/
/* Static function prototypes */
/*---------------------------------------------------------------------------*/
static int cuddZddSymmSiftingAux (DdManager *table, int x, int x_low, int x_high);
static int cuddZddSymmSiftingConvAux (DdManager *table, int x, int x_low, int x_high);
static Move * cuddZddSymmSifting_up (DdManager *table, int x, int x_low, int initial_size);
static Move * cuddZddSymmSifting_down (DdManager *table, int x, int x_high, int initial_size);
static int cuddZddSymmSiftingBackward (DdManager *table, Move *moves, int size);
static int zdd_group_move (DdManager *table, int x, int y, Move **moves);
static int zdd_group_move_backward (DdManager *table, int x, int y);
static void cuddZddSymmSummary (DdManager *table, int lower, int upper, int *symvars, int *symgroups);
/** \endcond */
/*---------------------------------------------------------------------------*/
/* Definition of exported functions */
/*---------------------------------------------------------------------------*/
/**
@brief Prints statistics on symmetric %ZDD variables.
@sideeffect None
*/
void
Cudd_zddSymmProfile(
DdManager * table,
int lower,
int upper)
{
int i, x, gbot;
int TotalSymm = 0;
int TotalSymmGroups = 0;
for (i = lower; i < upper; i++) {
if (table->subtableZ[i].next != (unsigned) i) {
x = i;
(void) fprintf(table->out,"Group:");
do {
(void) fprintf(table->out," %d", table->invpermZ[x]);
TotalSymm++;
gbot = x;
x = table->subtableZ[x].next;
} while (x != i);
TotalSymmGroups++;
#ifdef DD_DEBUG
assert(table->subtableZ[gbot].next == (unsigned) i);
#endif
i = gbot;
(void) fprintf(table->out,"\n");
}
}
(void) fprintf(table->out,"Total Symmetric = %d\n", TotalSymm);
(void) fprintf(table->out,"Total Groups = %d\n", TotalSymmGroups);
} /* end of Cudd_zddSymmProfile */
/*---------------------------------------------------------------------------*/
/* Definition of internal functions */
/*---------------------------------------------------------------------------*/
/**
@brief Checks for symmetry of x and y.
@details Ignores projection functions, unless they are isolated.
@return 1 in case of symmetry; 0 otherwise.
@sideeffect None
*/
int
cuddZddSymmCheck(
DdManager * table,
int x,
int y)
{
int i;
DdNode *f, *f0, *f1, *f01, *f00, *f11, *f10;
int yindex;
int xsymmy = 1;
int xsymmyp = 1;
int arccount = 0;
int TotalRefCount = 0;
int symm_found;
DdNode *empty = table->zero;
yindex = table->invpermZ[y];
for (i = table->subtableZ[x].slots - 1; i >= 0; i--) {
f = table->subtableZ[x].nodelist[i];
while (f != NULL) {
/* Find f1, f0, f11, f10, f01, f00 */
f1 = cuddT(f);
f0 = cuddE(f);
if ((int) f1->index == yindex) {
f11 = cuddT(f1);
f10 = cuddE(f1);
if (f10 != empty)
arccount++;
} else {
if ((int) f0->index != yindex) {
return(0); /* f bypasses layer y */
}
f11 = empty;
f10 = f1;
}
if ((int) f0->index == yindex) {
f01 = cuddT(f0);
f00 = cuddE(f0);
if (f00 != empty)
arccount++;
} else {
f01 = empty;
f00 = f0;
}
if (f01 != f10)
xsymmy = 0;
if (f11 != f00)
xsymmyp = 0;
if ((xsymmy == 0) && (xsymmyp == 0))
return(0);
f = f->next;
} /* for each element of the collision list */
} /* for each slot of the subtable */
/* Calculate the total reference counts of y
** whose else arc is not empty.
*/
for (i = table->subtableZ[y].slots - 1; i >= 0; i--) {
f = table->subtableZ[y].nodelist[i];
while (f != NIL(DdNode)) {
if (cuddE(f) != empty)
TotalRefCount += f->ref;
f = f->next;
}
}
symm_found = (arccount == TotalRefCount);
#if defined(DD_DEBUG) && defined(DD_VERBOSE)
if (symm_found) {
int xindex = table->invpermZ[x];
(void) fprintf(table->out,
"Found symmetry! x =%d\ty = %d\tPos(%d,%d)\n",
xindex,yindex,x,y);
}
#endif
return(symm_found);
} /* end cuddZddSymmCheck */
/**
@brief Symmetric sifting algorithm for ZDDs.
@details Assumes that no dead nodes are present.
<ol>
<li> Order all the variables according to the number of entries in
each unique subtable.
<li> Sift the variable up and down, remembering each time the total
size of the %ZDD heap and grouping variables that are symmetric.
<li> Select the best permutation.
<li> Repeat 3 and 4 for all variables.
</ol>
@return 1 plus the number of symmetric variables if successful; 0
otherwise.
@sideeffect None
@see cuddZddSymmSiftingConv
*/
int
cuddZddSymmSifting(
DdManager * table,
int lower,
int upper)
{
int i;
IndexKey *var;
int nvars;
int x;
int result;
int symvars;
int symgroups;
int iteration;
#ifdef DD_STATS
int previousSize;
#endif
nvars = table->sizeZ;
/* Find order in which to sift variables. */
var = ALLOC(IndexKey, nvars);
if (var == NULL) {
table->errorCode = CUDD_MEMORY_OUT;
goto cuddZddSymmSiftingOutOfMem;
}
for (i = 0; i < nvars; i++) {
x = table->permZ[i];
var[i].index = i;
var[i].keys = table->subtableZ[x].keys;
}
util_qsort(var, nvars, sizeof(IndexKey), cuddZddUniqueCompare);
/* Initialize the symmetry of each subtable to itself. */
for (i = lower; i <= upper; i++)
table->subtableZ[i].next = i;
iteration = ddMin(table->siftMaxVar, nvars);
for (i = 0; i < iteration; i++) {
if (table->zddTotalNumberSwapping >= table->siftMaxSwap)
break;
if (util_cpu_time() - table->startTime > table->timeLimit) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
if (table->terminationCallback != NULL &&
table->terminationCallback(table->tcbArg)) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
x = table->permZ[var[i].index];
#ifdef DD_STATS
previousSize = table->keysZ;
#endif
if (x < lower || x > upper) continue;
if (table->subtableZ[x].next == (unsigned) x) {
result = cuddZddSymmSiftingAux(table, x, lower, upper);
if (!result)
goto cuddZddSymmSiftingOutOfMem;
#ifdef DD_STATS
if (table->keysZ < (unsigned) previousSize) {
(void) fprintf(table->out,"-");
} else if (table->keysZ > (unsigned) previousSize) {
(void) fprintf(table->out,"+");
#ifdef DD_VERBOSE
(void) fprintf(table->out,"\nSize increased from %d to %d while sifting variable %d\n", previousSize, table->keysZ, var[i].index);
#endif
} else {
(void) fprintf(table->out,"=");
}
fflush(table->out);
#endif
}
}
FREE(var);
cuddZddSymmSummary(table, lower, upper, &symvars, &symgroups);
#ifdef DD_STATS
(void) fprintf(table->out,"\n#:S_SIFTING %8d: symmetric variables\n",symvars);
(void) fprintf(table->out,"#:G_SIFTING %8d: symmetric groups\n",symgroups);
#endif
return(1+symvars);
cuddZddSymmSiftingOutOfMem:
if (var != NULL)
FREE(var);
return(0);
} /* end of cuddZddSymmSifting */
/**
@brief Symmetric sifting to convergence algorithm for ZDDs.
@details Assumes that no dead nodes are present.
<ol>
<li> Order all the variables according to the number of entries in
each unique subtable.
<li> Sift the variable up and down, remembering each time the total
size of the %ZDD heap and grouping variables that are symmetric.
<li> Select the best permutation.
<li> Repeat 3 and 4 for all variables.
<li> Repeat 1-4 until no further improvement.
</ol>
@return 1 plus the number of symmetric variables if successful; 0
otherwise.
@sideeffect None
@see cuddZddSymmSifting
*/
int
cuddZddSymmSiftingConv(
DdManager * table,
int lower,
int upper)
{
int i;
IndexKey *var;
int nvars;
int initialSize;
int x;
int result;
int symvars;
int symgroups;
int classes;
int iteration;
#ifdef DD_STATS
int previousSize;
#endif
initialSize = table->keysZ;
nvars = table->sizeZ;
/* Find order in which to sift variables. */
var = ALLOC(IndexKey, nvars);
if (var == NULL) {
table->errorCode = CUDD_MEMORY_OUT;
goto cuddZddSymmSiftingConvOutOfMem;
}
for (i = 0; i < nvars; i++) {
x = table->permZ[i];
var[i].index = i;
var[i].keys = table->subtableZ[x].keys;
}
util_qsort(var, nvars, sizeof(IndexKey), cuddZddUniqueCompare);
/* Initialize the symmetry of each subtable to itself
** for first pass of converging symmetric sifting.
*/
for (i = lower; i <= upper; i++)
table->subtableZ[i].next = i;
iteration = ddMin(table->siftMaxVar, table->sizeZ);
for (i = 0; i < iteration; i++) {
if (table->zddTotalNumberSwapping >= table->siftMaxSwap)
break;
if (util_cpu_time() - table->startTime > table->timeLimit) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
if (table->terminationCallback != NULL &&
table->terminationCallback(table->tcbArg)) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
x = table->permZ[var[i].index];
if (x < lower || x > upper) continue;
/* Only sift if not in symmetry group already. */
if (table->subtableZ[x].next == (unsigned) x) {
#ifdef DD_STATS
previousSize = table->keysZ;
#endif
result = cuddZddSymmSiftingAux(table, x, lower, upper);
if (!result)
goto cuddZddSymmSiftingConvOutOfMem;
#ifdef DD_STATS
if (table->keysZ < (unsigned) previousSize) {
(void) fprintf(table->out,"-");
} else if (table->keysZ > (unsigned) previousSize) {
(void) fprintf(table->out,"+");
#ifdef DD_VERBOSE
(void) fprintf(table->out,"\nSize increased from %d to %d while sifting variable %d\n", previousSize, table->keysZ, var[i].index);
#endif
} else {
(void) fprintf(table->out,"=");
}
fflush(table->out);
#endif
}
}
/* Sifting now until convergence. */
while ((unsigned) initialSize > table->keysZ) {
initialSize = table->keysZ;
#ifdef DD_STATS
(void) fprintf(table->out,"\n");
#endif
/* Here we consider only one representative for each symmetry class. */
for (x = lower, classes = 0; x <= upper; x++, classes++) {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
/* Here x is the largest index in a group.
** Groups consists of adjacent variables.
** Hence, the next increment of x will move it to a new group.
*/
i = table->invpermZ[x];
var[classes].index = i;
var[classes].keys = table->subtableZ[x].keys;
}
util_qsort(var,classes,sizeof(IndexKey),cuddZddUniqueCompare);
/* Now sift. */
iteration = ddMin(table->siftMaxVar, nvars);
for (i = 0; i < iteration; i++) {
if (table->zddTotalNumberSwapping >= table->siftMaxSwap)
break;
if (util_cpu_time() - table->startTime > table->timeLimit) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
if (table->terminationCallback != NULL &&
table->terminationCallback(table->tcbArg)) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
x = table->permZ[var[i].index];
if ((unsigned) x >= table->subtableZ[x].next) {
#ifdef DD_STATS
previousSize = table->keysZ;
#endif
result = cuddZddSymmSiftingConvAux(table, x, lower, upper);
if (!result)
goto cuddZddSymmSiftingConvOutOfMem;
#ifdef DD_STATS
if (table->keysZ < (unsigned) previousSize) {
(void) fprintf(table->out,"-");
} else if (table->keysZ > (unsigned) previousSize) {
(void) fprintf(table->out,"+");
#ifdef DD_VERBOSE
(void) fprintf(table->out,"\nSize increased from %d to %d while sifting variable %d\n", previousSize, table->keysZ, var[i].index);
#endif
} else {
(void) fprintf(table->out,"=");
}
fflush(table->out);
#endif
}
} /* for */
}
cuddZddSymmSummary(table, lower, upper, &symvars, &symgroups);
#ifdef DD_STATS
(void) fprintf(table->out,"\n#:S_SIFTING %8d: symmetric variables\n",
symvars);
(void) fprintf(table->out,"#:G_SIFTING %8d: symmetric groups\n",
symgroups);
#endif
FREE(var);
return(1+symvars);
cuddZddSymmSiftingConvOutOfMem:
if (var != NULL)
FREE(var);
return(0);
} /* end of cuddZddSymmSiftingConv */
/*---------------------------------------------------------------------------*/
/* Definition of static functions */
/*---------------------------------------------------------------------------*/
/**
@brief Given x_low <= x <= x_high moves x up and down between the
boundaries.
@details Finds the best position and does the required changes.
Assumes that x is not part of a symmetry group.
@return 1 if successful; 0 otherwise.
@sideeffect None
*/
static int
cuddZddSymmSiftingAux(
DdManager * table,
int x,
int x_low,
int x_high)
{
Move *move;
Move *move_up; /* list of up move */
Move *move_down; /* list of down move */
int initial_size;
int result;
int i;
int topbot; /* index to either top or bottom of symmetry group */
int init_group_size, final_group_size;
initial_size = table->keysZ;
move_down = NULL;
move_up = NULL;
/* Look for consecutive symmetries above x. */
for (i = x; i > x_low; i--) {
if (!cuddZddSymmCheck(table, i - 1, i))
break;
/* find top of i-1's symmetry */
topbot = table->subtableZ[i - 1].next;
table->subtableZ[i - 1].next = i;
table->subtableZ[x].next = topbot;
/* x is bottom of group so its symmetry is top of i-1's
group */
i = topbot + 1; /* add 1 for i--, new i is top of symm group */
}
/* Look for consecutive symmetries below x. */
for (i = x; i < x_high; i++) {
if (!cuddZddSymmCheck(table, i, i + 1))
break;
/* find bottom of i+1's symm group */
topbot = i + 1;
while ((unsigned) topbot < table->subtableZ[topbot].next)
topbot = table->subtableZ[topbot].next;
table->subtableZ[topbot].next = table->subtableZ[i].next;
table->subtableZ[i].next = i + 1;
i = topbot - 1; /* add 1 for i++,
new i is bottom of symm group */
}
/* Now x maybe in the middle of a symmetry group. */
if (x == x_low) { /* Sift down */
/* Find bottom of x's symm group */
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
i = table->subtableZ[x].next;
init_group_size = x - i + 1;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
/* after that point x --> x_high, unless early term */
if (move_down == ZDD_MV_OOM)
goto cuddZddSymmSiftingAuxOutOfMem;
if (move_down == NULL ||
table->subtableZ[move_down->y].next != move_down->y) {
/* symmetry detected may have to make another complete
pass */
if (move_down != NULL)
x = move_down->y;
else
x = table->subtableZ[x].next;
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
final_group_size = i - x + 1;
if (init_group_size == final_group_size) {
/* No new symmetry groups detected,
return to best position */
result = cuddZddSymmSiftingBackward(table,
move_down, initial_size);
}
else {
initial_size = table->keysZ;
move_up = cuddZddSymmSifting_up(table, x, x_low,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingAuxOutOfMem;
}
else if (x == x_high) { /* Sift up */
/* Find top of x's symm group */
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
x = table->subtableZ[x].next;
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
init_group_size = i - x + 1;
move_up = cuddZddSymmSifting_up(table, x, x_low, initial_size);
/* after that point x --> x_low, unless early term */
if (move_up == ZDD_MV_OOM)
goto cuddZddSymmSiftingAuxOutOfMem;
if (move_up == NULL ||
table->subtableZ[move_up->x].next != move_up->x) {
/* symmetry detected may have to make another complete
pass */
if (move_up != NULL)
x = move_up->x;
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
}
i = table->subtableZ[x].next;
final_group_size = x - i + 1;
if (init_group_size == final_group_size) {
/* No new symmetry groups detected,
return to best position */
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
else {
initial_size = table->keysZ;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingAuxOutOfMem;
}
else if ((x - x_low) > (x_high - x)) { /* must go down first:
shorter */
/* Find bottom of x's symm group */
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
/* after that point x --> x_high, unless early term */
if (move_down == ZDD_MV_OOM)
goto cuddZddSymmSiftingAuxOutOfMem;
if (move_down != NULL) {
x = move_down->y;
}
else {
x = table->subtableZ[x].next;
}
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
init_group_size = i - x + 1;
move_up = cuddZddSymmSifting_up(table, x, x_low, initial_size);
if (move_up == ZDD_MV_OOM)
goto cuddZddSymmSiftingAuxOutOfMem;
if (move_up == NULL ||
table->subtableZ[move_up->x].next != move_up->x) {
/* symmetry detected may have to make another complete
pass */
if (move_up != NULL) {
x = move_up->x;
}
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
}
i = table->subtableZ[x].next;
final_group_size = x - i + 1;
if (init_group_size == final_group_size) {
/* No new symmetry groups detected,
return to best position */
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
else {
while (move_down != NULL) {
move = move_down->next;
cuddDeallocMove(table, move_down);
move_down = move;
}
initial_size = table->keysZ;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingAuxOutOfMem;
}
else { /* moving up first:shorter */
/* Find top of x's symmetry group */
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
x = table->subtableZ[x].next;
move_up = cuddZddSymmSifting_up(table, x, x_low, initial_size);
/* after that point x --> x_high, unless early term */
if (move_up == ZDD_MV_OOM)
goto cuddZddSymmSiftingAuxOutOfMem;
if (move_up != NULL) {
x = move_up->x;
}
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
}
i = table->subtableZ[x].next;
init_group_size = x - i + 1;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
if (move_down == ZDD_MV_OOM)
goto cuddZddSymmSiftingAuxOutOfMem;
if (move_down == NULL ||
table->subtableZ[move_down->y].next != move_down->y) {
/* symmetry detected may have to make another complete
pass */
if (move_down != NULL) {
x = move_down->y;
}
else {
x = table->subtableZ[x].next;
}
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
final_group_size = i - x + 1;
if (init_group_size == final_group_size) {
/* No new symmetries detected,
go back to best position */
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
}
else {
while (move_up != NULL) {
move = move_up->next;
cuddDeallocMove(table, move_up);
move_up = move;
}
initial_size = table->keysZ;
move_up = cuddZddSymmSifting_up(table, x, x_low,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingAuxOutOfMem;
}
while (move_down != NULL) {
move = move_down->next;
cuddDeallocMove(table, move_down);
move_down = move;
}
while (move_up != NULL) {
move = move_up->next;
cuddDeallocMove(table, move_up);
move_up = move;
}
return(1);
cuddZddSymmSiftingAuxOutOfMem:
if (move_down != ZDD_MV_OOM) {
while (move_down != NULL) {
move = move_down->next;
cuddDeallocMove(table, move_down);
move_down = move;
}
}
if (move_up != ZDD_MV_OOM) {
while (move_up != NULL) {
move = move_up->next;
cuddDeallocMove(table, move_up);
move_up = move;
}
}
return(0);
} /* end of cuddZddSymmSiftingAux */
/**
@brief Given x_low <= x <= x_high moves x up and down between the
boundaries.
@details Finds the best position and does the required changes.
Assumes that x is either an isolated variable, or it is the bottom of
a symmetry group. All symmetries may not have been found, because of
exceeded growth limit.
@return 1 if successful; 0 otherwise.
@sideeffect None
*/
static int
cuddZddSymmSiftingConvAux(
DdManager * table,
int x,
int x_low,
int x_high)
{
Move *move;
Move *move_up; /* list of up move */
Move *move_down; /* list of down move */
int initial_size;
int result;
int i;
int init_group_size, final_group_size;
initial_size = table->keysZ;
move_down = NULL;
move_up = NULL;
if (x == x_low) { /* Sift down */
i = table->subtableZ[x].next;
init_group_size = x - i + 1;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
/* after that point x --> x_high, unless early term */
if (move_down == ZDD_MV_OOM)
goto cuddZddSymmSiftingConvAuxOutOfMem;
if (move_down == NULL ||
table->subtableZ[move_down->y].next != move_down->y) {
/* symmetry detected may have to make another complete
pass */
if (move_down != NULL)
x = move_down->y;
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
x = table->subtableZ[x].next;
}
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
final_group_size = i - x + 1;
if (init_group_size == final_group_size) {
/* No new symmetries detected,
go back to best position */
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
}
else {
initial_size = table->keysZ;
move_up = cuddZddSymmSifting_up(table, x, x_low,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingConvAuxOutOfMem;
}
else if (x == x_high) { /* Sift up */
/* Find top of x's symm group */
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
x = table->subtableZ[x].next;
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
init_group_size = i - x + 1;
move_up = cuddZddSymmSifting_up(table, x, x_low, initial_size);
/* after that point x --> x_low, unless early term */
if (move_up == ZDD_MV_OOM)
goto cuddZddSymmSiftingConvAuxOutOfMem;
if (move_up == NULL ||
table->subtableZ[move_up->x].next != move_up->x) {
/* symmetry detected may have to make another complete
pass */
if (move_up != NULL)
x = move_up->x;
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
}
i = table->subtableZ[x].next;
final_group_size = x - i + 1;
if (init_group_size == final_group_size) {
/* No new symmetry groups detected,
return to best position */
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
else {
initial_size = table->keysZ;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingConvAuxOutOfMem;
}
else if ((x - x_low) > (x_high - x)) { /* must go down first:
shorter */
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
/* after that point x --> x_high */
if (move_down == ZDD_MV_OOM)
goto cuddZddSymmSiftingConvAuxOutOfMem;
if (move_down != NULL) {
x = move_down->y;
}
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
x = table->subtableZ[x].next;
}
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
init_group_size = i - x + 1;
move_up = cuddZddSymmSifting_up(table, x, x_low, initial_size);
if (move_up == ZDD_MV_OOM)
goto cuddZddSymmSiftingConvAuxOutOfMem;
if (move_up == NULL ||
table->subtableZ[move_up->x].next != move_up->x) {
/* symmetry detected may have to make another complete
pass */
if (move_up != NULL) {
x = move_up->x;
}
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
}
i = table->subtableZ[x].next;
final_group_size = x - i + 1;
if (init_group_size == final_group_size) {
/* No new symmetry groups detected,
return to best position */
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
else {
while (move_down != NULL) {
move = move_down->next;
cuddDeallocMove(table, move_down);
move_down = move;
}
initial_size = table->keysZ;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingConvAuxOutOfMem;
}
else { /* moving up first:shorter */
/* Find top of x's symmetry group */
x = table->subtableZ[x].next;
move_up = cuddZddSymmSifting_up(table, x, x_low, initial_size);
/* after that point x --> x_high, unless early term */
if (move_up == ZDD_MV_OOM)
goto cuddZddSymmSiftingConvAuxOutOfMem;
if (move_up != NULL) {
x = move_up->x;
}
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
}
i = table->subtableZ[x].next;
init_group_size = x - i + 1;
move_down = cuddZddSymmSifting_down(table, x, x_high,
initial_size);
if (move_down == ZDD_MV_OOM)
goto cuddZddSymmSiftingConvAuxOutOfMem;
if (move_down == NULL ||
table->subtableZ[move_down->y].next != move_down->y) {
/* symmetry detected may have to make another complete
pass */
if (move_down != NULL) {
x = move_down->y;
}
else {
while ((unsigned) x < table->subtableZ[x].next)
x = table->subtableZ[x].next;
x = table->subtableZ[x].next;
}
i = x;
while ((unsigned) i < table->subtableZ[i].next) {
i = table->subtableZ[i].next;
}
final_group_size = i - x + 1;
if (init_group_size == final_group_size) {
/* No new symmetries detected,
go back to best position */
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
}
else {
while (move_up != NULL) {
move = move_up->next;
cuddDeallocMove(table, move_up);
move_up = move;
}
initial_size = table->keysZ;
move_up = cuddZddSymmSifting_up(table, x, x_low,
initial_size);
result = cuddZddSymmSiftingBackward(table, move_up,
initial_size);
}
}
else {
result = cuddZddSymmSiftingBackward(table, move_down,
initial_size);
/* move backward and stop at best position */
}
if (!result)
goto cuddZddSymmSiftingConvAuxOutOfMem;
}
while (move_down != NULL) {
move = move_down->next;
cuddDeallocMove(table, move_down);
move_down = move;
}
while (move_up != NULL) {
move = move_up->next;
cuddDeallocMove(table, move_up);
move_up = move;
}
return(1);
cuddZddSymmSiftingConvAuxOutOfMem:
if (move_down != ZDD_MV_OOM) {
while (move_down != NULL) {
move = move_down->next;
cuddDeallocMove(table, move_down);
move_down = move;
}
}
if (move_up != ZDD_MV_OOM) {
while (move_up != NULL) {
move = move_up->next;
cuddDeallocMove(table, move_up);
move_up = move;
}
}
return(0);
} /* end of cuddZddSymmSiftingConvAux */
/**
@brief Moves x up until either it reaches the bound (x_low) or
the size of the %ZDD heap increases too much.
@details Assumes that x is the top of a symmetry group. Checks x
for symmetry to the adjacent variables. If symmetry is found, the
symmetry group of x is merged with the symmetry group of the other
variable.
@return the set of moves in case of success; ZDD_MV_OOM if memory is
full.
@sideeffect None
*/
static Move *
cuddZddSymmSifting_up(
DdManager * table,
int x,
int x_low,
int initial_size)
{
Move *moves;
Move *move;
int y;
int size;
int limit_size = initial_size;
int i, gytop;
moves = NULL;
y = cuddZddNextLow(table, x);
while (y >= x_low) {
gytop = table->subtableZ[y].next;
if (cuddZddSymmCheck(table, y, x)) {
/* Symmetry found, attach symm groups */
table->subtableZ[y].next = x;
i = table->subtableZ[x].next;
while (table->subtableZ[i].next != (unsigned) x)
i = table->subtableZ[i].next;
table->subtableZ[i].next = gytop;
}
else if ((table->subtableZ[x].next == (unsigned) x) &&
(table->subtableZ[y].next == (unsigned) y)) {
/* x and y have self symmetry */
size = cuddZddSwapInPlace(table, y, x);
if (size == 0)
goto cuddZddSymmSifting_upOutOfMem;
move = (Move *)cuddDynamicAllocNode(table);
if (move == NULL)
goto cuddZddSymmSifting_upOutOfMem;
move->x = y;
move->y = x;
move->size = size;
move->next = moves;
moves = move;
if ((double)size >
(double)limit_size * table->maxGrowth)
return(moves);
if (size < limit_size)
limit_size = size;
}
else { /* Group move */
size = zdd_group_move(table, y, x, &moves);
if ((double)size >
(double)limit_size * table->maxGrowth)
return(moves);
if (size < limit_size)
limit_size = size;
}
x = gytop;
y = cuddZddNextLow(table, x);
}
return(moves);
cuddZddSymmSifting_upOutOfMem:
while (moves != NULL) {
move = moves->next;
cuddDeallocMove(table, moves);
moves = move;
}
return(ZDD_MV_OOM);
} /* end of cuddZddSymmSifting_up */
/**
@brief Moves x down until either it reaches the bound (x_high) or
the size of the %ZDD heap increases too much.
@details Assumes that x is the bottom of a symmetry group. Checks x
for symmetry to the adjacent variables. If symmetry is found, the
symmetry group of x is merged with the symmetry group of the other
variable.
@return the set of moves in case of success; ZDD_MV_OOM if memory is
full.
@sideeffect None
*/
static Move *
cuddZddSymmSifting_down(
DdManager * table,
int x,
int x_high,
int initial_size)
{
Move *moves;
Move *move;
int y;
int size;
int limit_size = initial_size;
int i, gxtop, gybot;
moves = NULL;
y = cuddZddNextHigh(table, x);
while (y <= x_high) {
gybot = table->subtableZ[y].next;
while (table->subtableZ[gybot].next != (unsigned) y)
gybot = table->subtableZ[gybot].next;
if (cuddZddSymmCheck(table, x, y)) {
/* Symmetry found, attach symm groups */
gxtop = table->subtableZ[x].next;
table->subtableZ[x].next = y;
i = table->subtableZ[y].next;
while (table->subtableZ[i].next != (unsigned) y)
i = table->subtableZ[i].next;
table->subtableZ[i].next = gxtop;
}
else if ((table->subtableZ[x].next == (unsigned) x) &&
(table->subtableZ[y].next == (unsigned) y)) {
/* x and y have self symmetry */
size = cuddZddSwapInPlace(table, x, y);
if (size == 0)
goto cuddZddSymmSifting_downOutOfMem;
move = (Move *)cuddDynamicAllocNode(table);
if (move == NULL)
goto cuddZddSymmSifting_downOutOfMem;
move->x = x;
move->y = y;
move->size = size;
move->next = moves;
moves = move;
if ((double)size >
(double)limit_size * table->maxGrowth)
return(moves);
if (size < limit_size)
limit_size = size;
}
else { /* Group move */
size = zdd_group_move(table, x, y, &moves);
if ((double)size >
(double)limit_size * table->maxGrowth)
return(moves);
if (size < limit_size)
limit_size = size;
}
x = gybot;
y = cuddZddNextHigh(table, x);
}
return(moves);
cuddZddSymmSifting_downOutOfMem:
while (moves != NULL) {
move = moves->next;
cuddDeallocMove(table, moves);
moves = move;
}
return(ZDD_MV_OOM);
} /* end of cuddZddSymmSifting_down */
/**
@brief Given a set of moves, returns the %ZDD heap to the position
giving the minimum size.
@details In case of ties, returns to the closest position giving the
minimum size.
@return 1 in case of success; 0 otherwise.
@sideeffect None
*/
static int
cuddZddSymmSiftingBackward(
DdManager * table,
Move * moves,
int size)
{
int i;
int i_best;
Move *move;
int res;
i_best = -1;
for (move = moves, i = 0; move != NULL; move = move->next, i++) {
if (move->size < size) {
i_best = i;
size = move->size;
}
}
for (move = moves, i = 0; move != NULL; move = move->next, i++) {
if (i == i_best) break;
if ((table->subtableZ[move->x].next == move->x) &&
(table->subtableZ[move->y].next == move->y)) {
res = cuddZddSwapInPlace(table, move->x, move->y);
if (!res) return(0);
}
else { /* Group move necessary */
res = zdd_group_move_backward(table, move->x, move->y);
}
if (i_best == -1 && res == size)
break;
}
return(1);
} /* end of cuddZddSymmSiftingBackward */
/**
@brief Swaps two groups.
@details x is assumed to be the bottom variable of the first
group. y is assumed to be the top variable of the second group.
Updates the list of moves.
@return the number of keys in the table if successful; 0 otherwise.
@sideeffect None
*/
static int
zdd_group_move(
DdManager * table,
int x,
int y,
Move ** moves)
{
Move *move;
int size;
int i, temp, gxtop, gxbot, gybot, yprev;
int swapx = 0, swapy = 0;
#ifdef DD_DEBUG
assert(x < y); /* we assume that x < y */
#endif
/* Find top and bottom for the two groups. */
gxtop = table->subtableZ[x].next;
gxbot = x;
gybot = table->subtableZ[y].next;
while (table->subtableZ[gybot].next != (unsigned) y)
gybot = table->subtableZ[gybot].next;
yprev = gybot;
while (x <= y) {
while (y > gxtop) {
/* Set correct symmetries. */
temp = table->subtableZ[x].next;
if (temp == x)
temp = y;
i = gxtop;
for (;;) {
if (table->subtableZ[i].next == (unsigned) x) {
table->subtableZ[i].next = y;
break;
} else {
i = table->subtableZ[i].next;
}
}
if (table->subtableZ[y].next != (unsigned) y) {
table->subtableZ[x].next = table->subtableZ[y].next;
} else {
table->subtableZ[x].next = x;
}
if (yprev != y) {
table->subtableZ[yprev].next = x;
} else {
yprev = x;
}
table->subtableZ[y].next = temp;
size = cuddZddSwapInPlace(table, x, y);
if (size == 0)
goto zdd_group_moveOutOfMem;
swapx = x;
swapy = y;
y = x;
x--;
} /* while y > gxtop */
/* Trying to find the next y. */
if (table->subtableZ[y].next > (unsigned) y) {
y = table->subtableZ[y].next;
}
yprev = gxtop;
gxtop++;
gxbot++;
x = gxbot;
} /* while x <= y, end of group movement */
move = (Move *)cuddDynamicAllocNode(table);
if (move == NULL)
goto zdd_group_moveOutOfMem;
move->x = swapx;
move->y = swapy;
move->size = table->keysZ;
move->next = *moves;
*moves = move;
return(table->keysZ);
zdd_group_moveOutOfMem:
while (*moves != NULL) {
move = (*moves)->next;
cuddDeallocMove(table, *moves);
*moves = move;
}
return(0);
} /* end of zdd_group_move */
/**
@brief Undoes the swap of two groups.
@details x is assumed to be the bottom variable of the first
group. y is assumed to be the top variable of the second group.
@return 1 if successful; 0 otherwise.
@sideeffect None
*/
static int
zdd_group_move_backward(
DdManager * table,
int x,
int y)
{
int size = table->keysZ;
int i, temp, gxtop, gxbot, gybot, yprev;
#ifdef DD_DEBUG
assert(x < y); /* we assume that x < y */
#endif
/* Find top and bottom of the two groups. */
gxtop = table->subtableZ[x].next;
gxbot = x;
gybot = table->subtableZ[y].next;
while (table->subtableZ[gybot].next != (unsigned) y)
gybot = table->subtableZ[gybot].next;
yprev = gybot;
while (x <= y) {
while (y > gxtop) {
/* Set correct symmetries. */
temp = table->subtableZ[x].next;
if (temp == x)
temp = y;
i = gxtop;
for (;;) {
if (table->subtableZ[i].next == (unsigned) x) {
table->subtableZ[i].next = y;
break;
} else {
i = table->subtableZ[i].next;
}
}
if (table->subtableZ[y].next != (unsigned) y) {
table->subtableZ[x].next = table->subtableZ[y].next;
} else {
table->subtableZ[x].next = x;
}
if (yprev != y) {
table->subtableZ[yprev].next = x;
} else {
yprev = x;
}
table->subtableZ[y].next = temp;
size = cuddZddSwapInPlace(table, x, y);
if (size == 0)
return(0);
y = x;
x--;
} /* while y > gxtop */
/* Trying to find the next y. */
if (table->subtableZ[y].next > (unsigned) y) {
y = table->subtableZ[y].next;
}
yprev = gxtop;
gxtop++;
gxbot++;
x = gxbot;
} /* while x <= y, end of group movement backward */
return(size);
} /* end of zdd_group_move_backward */
/**
@brief Counts numbers of symmetric variables and symmetry groups.
@sideeffect None
*/
static void
cuddZddSymmSummary(
DdManager * table,
int lower,
int upper,
int * symvars,
int * symgroups)
{
int i,x,gbot;
int TotalSymm = 0;
int TotalSymmGroups = 0;
for (i = lower; i <= upper; i++) {
if (table->subtableZ[i].next != (unsigned) i) {
TotalSymmGroups++;
x = i;
do {
TotalSymm++;
gbot = x;
x = table->subtableZ[x].next;
} while (x != i);
#ifdef DD_DEBUG
assert(table->subtableZ[gbot].next == (unsigned) i);
#endif
i = gbot;
}
}
*symvars = TotalSymm;
*symgroups = TotalSymmGroups;
return;
} /* end of cuddZddSymmSummary */