src/cuBdd/cuddSubsetHB.c File Reference

#include "util.h"
#include "cuddInt.h"

Include dependency graph for cuddSubsetHB.c:

Go to the source code of this file.

Data Structures
struct	NodeData
Defines
#define	DBL_MAX_EXP   1024
#define	DEFAULT_PAGE_SIZE   2048
#define	DEFAULT_NODE_DATA_PAGE_SIZE   1024
#define	INITIAL_PAGES   128
Typedefs
typedef struct NodeData	NodeData_t
Functions
static void	ResizeNodeDataPages (void)
static void	ResizeCountMintermPages (void)
static void	ResizeCountNodePages (void)
static double	SubsetCountMintermAux (DdNode *node, double max, st_table *table)
static st_table *	SubsetCountMinterm (DdNode *node, int nvars)
static int	SubsetCountNodesAux (DdNode *node, st_table *table, double max)
static int	SubsetCountNodes (DdNode *node, st_table *table, int nvars)
static void	StoreNodes (st_table *storeTable, DdManager *dd, DdNode *node)
static DdNode *	BuildSubsetBdd (DdManager *dd, DdNode *node, int *size, st_table *visitedTable, int threshold, st_table *storeTable, st_table *approxTable)
DdNode *	Cudd_SubsetHeavyBranch (DdManager *dd, DdNode *f, int numVars, int threshold)
DdNode *	Cudd_SupersetHeavyBranch (DdManager *dd, DdNode *f, int numVars, int threshold)
DdNode *	cuddSubsetHeavyBranch (DdManager *dd, DdNode *f, int numVars, int threshold)
Variables
static char rcsid[]	DD_UNUSED = "$Id: cuddSubsetHB.c,v 1.37 2009/02/20 02:14:58 fabio Exp $"
static int	memOut
static DdNode *	zero
static DdNode *	one
static double **	mintermPages
static int **	nodePages
static int **	lightNodePages
static double *	currentMintermPage
static double	max
static int *	currentNodePage
static int *	currentLightNodePage
static int	pageIndex
static int	page
static int	pageSize = DEFAULT_PAGE_SIZE
static int	maxPages
static NodeData_t *	currentNodeDataPage
static int	nodeDataPage
static int	nodeDataPageIndex
static NodeData_t **	nodeDataPages
static int	nodeDataPageSize = DEFAULT_NODE_DATA_PAGE_SIZE
static int	maxNodeDataPages

---

Define Documentation

#define DBL_MAX_EXP   1024

CFile***********************************************************************

FileName [cuddSubsetHB.c]

PackageName [cudd]

Synopsis [Procedure to subset the given BDD by choosing the heavier branches.]

Description [External procedures provided by this module:

• Cudd_SubsetHeavyBranch()
• Cudd_SupersetHeavyBranch()

Internal procedures included in this module:

• cuddSubsetHeavyBranch()

Static procedures included in this module:

• ResizeCountMintermPages();
• ResizeNodeDataPages()
• ResizeCountNodePages()
• SubsetCountMintermAux()
• SubsetCountMinterm()
• SubsetCountNodesAux()
• SubsetCountNodes()
• BuildSubsetBdd()

]

SeeAlso [cuddSubsetSP.c]

Author [Kavita Ravi]

Copyright [Copyright (c) 1995-2004, 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.]

Definition at line 74 of file cuddSubsetHB.c.

#define DEFAULT_NODE_DATA_PAGE_SIZE   1024

Definition at line 84 of file cuddSubsetHB.c.

#define DEFAULT_PAGE_SIZE   2048

Definition at line 83 of file cuddSubsetHB.c.

#define INITIAL_PAGES   128

Definition at line 85 of file cuddSubsetHB.c.

---

Typedef Documentation

typedef struct NodeData NodeData_t

Definition at line 109 of file cuddSubsetHB.c.

---

Function Documentation

static DdNode * BuildSubsetBdd	(	DdManager *	dd,
		DdNode *	node,
		int *	size,
		st_table *	visitedTable,
		int	threshold,
		st_table *	storeTable,
		st_table *	approxTable
	)			[static]

Function********************************************************************

Synopsis [Builds the subset BDD using the heavy branch method.]

Description [The procedure carries out the building of the subset BDD starting at the root. Using the three different counts labelling each node, the procedure chooses the heavier branch starting from the root and keeps track of the number of nodes it discards at each step, thus keeping count of the size of the subset BDD dynamically. Once the threshold is satisfied, the procedure then calls ITE to build the BDD.]

SideEffects [None]

SeeAlso []

Definition at line 1154 of file cuddSubsetHB.c.

{

    DdNode *Nv, *Nnv, *N, *topv, *neW;
    double minNv, minNnv;
    NodeData_t *currNodeQual;
    NodeData_t *currNodeQualT;
    NodeData_t *currNodeQualE;
    DdNode *ThenBranch, *ElseBranch;
    unsigned int topid;
    char *dummy;

#ifdef DEBUG
    num_calls++;
#endif
    /*If the size of the subset is below the threshold, dont do
      anything. */
    if ((*size) <= threshold) {
      /* store nodes below this, so we can recombine if possible */
      StoreNodes(storeTable, dd, node);
      return(node);
    }

    if (Cudd_IsConstant(node))
        return(node);

    /* Look up minterm count for this node. */
    if (!st_lookup(visitedTable, node, &currNodeQual)) {
        fprintf(dd->err,
                "Something is wrong, ought to be in node quality table\n");
    }

    /* Get children. */
    N = Cudd_Regular(node);
    Nv = Cudd_T(N);
    Nnv = Cudd_E(N);

    /* complement if necessary */
    Nv = Cudd_NotCond(Nv, Cudd_IsComplement(node));
    Nnv = Cudd_NotCond(Nnv, Cudd_IsComplement(node));

    if (!Cudd_IsConstant(Nv)) {
        /* find out minterms and nodes contributed by then child */
        if (!st_lookup(visitedTable, Nv, &currNodeQualT)) {
                fprintf(dd->out,"Something wrong, couldnt find nodes in node quality table\n");
                dd->errorCode = CUDD_INTERNAL_ERROR;
                return(NULL);
            }
        else {
            minNv = *(((NodeData_t *)currNodeQualT)->mintermPointer);
        }
    } else {
        if (Nv == zero) {
            minNv = 0;
        } else  {
            minNv = max;
        }
    }
    if (!Cudd_IsConstant(Nnv)) {
        /* find out minterms and nodes contributed by else child */
        if (!st_lookup(visitedTable, Nnv, &currNodeQualE)) {
            fprintf(dd->out,"Something wrong, couldnt find nodes in node quality table\n");
            dd->errorCode = CUDD_INTERNAL_ERROR;
            return(NULL);
        } else {
            minNnv = *(((NodeData_t *)currNodeQualE)->mintermPointer);
        }
    } else {
        if (Nnv == zero) {
            minNnv = 0;
        } else {
            minNnv = max;
        }
    }

    /* keep track of size of subset by subtracting the number of
     * differential nodes contributed by lighter child
     */
    *size = (*(size)) - (int)*(currNodeQual->lightChildNodesPointer);
    if (minNv >= minNnv) { /*SubsetCountNodesAux procedure takes
                             the Then branch in case of a tie */

        /* recur with the Then branch */
        ThenBranch = (DdNode *)BuildSubsetBdd(dd, Nv, size,
              visitedTable, threshold, storeTable, approxTable);
        if (ThenBranch == NULL) {
            return(NULL);
        }
        cuddRef(ThenBranch);
        /* The Else branch is either a node that already exists in the
         * subset, or one whose approximation has been computed, or
         * Zero.
         */
        if (st_lookup(storeTable, (char *)Cudd_Regular(Nnv), &dummy)) {
          ElseBranch = Nnv;
          cuddRef(ElseBranch);
        } else {
          if (st_lookup(approxTable, (char *)Nnv, &dummy)) {
            ElseBranch = (DdNode *)dummy;
            cuddRef(ElseBranch);
          } else {
            ElseBranch = zero;
            cuddRef(ElseBranch);
          }
        }

    }
    else {
        /* recur with the Else branch */
        ElseBranch = (DdNode *)BuildSubsetBdd(dd, Nnv, size,
                      visitedTable, threshold, storeTable, approxTable);
        if (ElseBranch == NULL) {
            return(NULL);
        }
        cuddRef(ElseBranch);
        /* The Then branch is either a node that already exists in the
         * subset, or one whose approximation has been computed, or
         * Zero.
         */
        if (st_lookup(storeTable, (char *)Cudd_Regular(Nv), &dummy)) {
          ThenBranch = Nv;
          cuddRef(ThenBranch);
        } else {
          if (st_lookup(approxTable, (char *)Nv, &dummy)) {
            ThenBranch = (DdNode *)dummy;
            cuddRef(ThenBranch);
          } else {
            ThenBranch = zero;
            cuddRef(ThenBranch);
          }
        }
    }

    /* construct the Bdd with the top variable and the two children */
    topid = Cudd_NodeReadIndex(N);
    topv = Cudd_ReadVars(dd, topid);
    cuddRef(topv);
    neW =  cuddBddIteRecur(dd, topv, ThenBranch, ElseBranch);
    if (neW != NULL) {
      cuddRef(neW);
    }
    Cudd_RecursiveDeref(dd, topv);
    Cudd_RecursiveDeref(dd, ThenBranch);
    Cudd_RecursiveDeref(dd, ElseBranch);


    if (neW == NULL)
        return(NULL);
    else {
        /* store this node in the store table */
        if (!st_lookup(storeTable, (char *)Cudd_Regular(neW), &dummy)) {
          cuddRef(neW);
          if (!st_insert(storeTable, (char *)Cudd_Regular(neW), NIL(char)))
              return (NULL);
        }
        /* store the approximation for this node */
        if (N !=  Cudd_Regular(neW)) {
            if (st_lookup(approxTable, (char *)node, &dummy)) {
                fprintf(dd->err, "This node should not be in the approximated table\n");
            } else {
                cuddRef(neW);
                if (!st_insert(approxTable, (char *)node, (char *)neW))
                    return(NULL);
            }
        }
        cuddDeref(neW);
        return(neW);
    }
} /* end of BuildSubsetBdd */

DdNode* Cudd_SubsetHeavyBranch	(	DdManager *	dd,
		DdNode *	f,
		int	numVars,
		int	threshold
	)

AutomaticEnd Function********************************************************************

Synopsis [Extracts a dense subset from a BDD with the heavy branch heuristic.]

Description [Extracts a dense subset from a BDD. This procedure builds a subset by throwing away one of the children of each node, starting from the root, until the result is small enough. The child that is eliminated from the result is the one that contributes the fewer minterms. Returns a pointer to the BDD of the subset if successful. NULL if the procedure runs out of memory. The parameter numVars is the maximum number of variables to be used in minterm calculation and node count calculation. The optimal number should be as close as possible to the size of the support of f. However, it is safe to pass the value returned by Cudd_ReadSize for numVars when the number of variables is under 1023. If numVars is larger than 1023, it will overflow. If a 0 parameter is passed then the procedure will compute a value which will avoid overflow but will cause underflow with 2046 variables or more.]

SideEffects [None]

SeeAlso [Cudd_SubsetShortPaths Cudd_SupersetHeavyBranch Cudd_ReadSize]

Definition at line 205 of file cuddSubsetHB.c.

{
    DdNode *subset;

    memOut = 0;
    do {
        dd->reordered = 0;
        subset = cuddSubsetHeavyBranch(dd, f, numVars, threshold);
    } while ((dd->reordered == 1) && (!memOut));

    return(subset);

} /* end of Cudd_SubsetHeavyBranch */

DdNode* Cudd_SupersetHeavyBranch	(	DdManager *	dd,
		DdNode *	f,
		int	numVars,
		int	threshold
	)

Function********************************************************************

Synopsis [Extracts a dense superset from a BDD with the heavy branch heuristic.]

Description [Extracts a dense superset from a BDD. The procedure is identical to the subset procedure except for the fact that it receives the complement of the given function. Extracting the subset of the complement function is equivalent to extracting the superset of the function. This procedure builds a superset by throwing away one of the children of each node starting from the root of the complement function, until the result is small enough. The child that is eliminated from the result is the one that contributes the fewer minterms. Returns a pointer to the BDD of the superset if successful. NULL if intermediate result causes the procedure to run out of memory. The parameter numVars is the maximum number of variables to be used in minterm calculation and node count calculation. The optimal number should be as close as possible to the size of the support of f. However, it is safe to pass the value returned by Cudd_ReadSize for numVars when the number of variables is under 1023. If numVars is larger than 1023, it will overflow. If a 0 parameter is passed then the procedure will compute a value which will avoid overflow but will cause underflow with 2046 variables or more.]

SideEffects [None]

SeeAlso [Cudd_SubsetHeavyBranch Cudd_SupersetShortPaths Cudd_ReadSize]

Definition at line 255 of file cuddSubsetHB.c.

{
    DdNode *subset, *g;

    g = Cudd_Not(f);
    memOut = 0;
    do {
        dd->reordered = 0;
        subset = cuddSubsetHeavyBranch(dd, g, numVars, threshold);
    } while ((dd->reordered == 1) && (!memOut));

    return(Cudd_NotCond(subset, (subset != NULL)));

} /* end of Cudd_SupersetHeavyBranch */

DdNode* cuddSubsetHeavyBranch	(	DdManager *	dd,
		DdNode *	f,
		int	numVars,
		int	threshold
	)

Function********************************************************************

Synopsis [The main procedure that returns a subset by choosing the heavier branch in the BDD.]

Description [Here a subset BDD is built by throwing away one of the children. Starting at root, annotate each node with the number of minterms (in terms of the total number of variables specified - numVars), number of nodes taken by the DAG rooted at this node and number of additional nodes taken by the child that has the lesser minterms. The child with the lower number of minterms is thrown away and a dyanmic count of the nodes of the subset is kept. Once the threshold is reached the subset is returned to the calling procedure.]

SideEffects [None]

SeeAlso [Cudd_SubsetHeavyBranch]

Definition at line 301 of file cuddSubsetHB.c.

{

    int i, *size;
    st_table *visitedTable;
    int numNodes;
    NodeData_t *currNodeQual;
    DdNode *subset;
    st_table *storeTable, *approxTable;
    char *key, *value;
    st_generator *stGen;

    if (f == NULL) {
        fprintf(dd->err, "Cannot subset, nil object\n");
        dd->errorCode = CUDD_INVALID_ARG;
        return(NULL);
    }

    one  = Cudd_ReadOne(dd);
    zero = Cudd_Not(one);

    /* If user does not know numVars value, set it to the maximum
     * exponent that the pow function can take. The -1 is due to the
     * discrepancy in the value that pow takes and the value that
     * log gives.
     */
    if (numVars == 0) {
        /* set default value */
        numVars = DBL_MAX_EXP - 1;
    }

    if (Cudd_IsConstant(f)) {
        return(f);
    }

    max = pow(2.0, (double)numVars);

    /* Create visited table where structures for node data are allocated and
       stored in a st_table */
    visitedTable = SubsetCountMinterm(f, numVars);
    if ((visitedTable == NULL) || memOut) {
        (void) fprintf(dd->err, "Out-of-memory; Cannot subset\n");
        dd->errorCode = CUDD_MEMORY_OUT;
        return(0);
    }
    numNodes = SubsetCountNodes(f, visitedTable, numVars);
    if (memOut) {
        (void) fprintf(dd->err, "Out-of-memory; Cannot subset\n");
        dd->errorCode = CUDD_MEMORY_OUT;
        return(0);
    }

    if (st_lookup(visitedTable, f, &currNodeQual) == 0) {
        fprintf(dd->err,
                "Something is wrong, ought to be node quality table\n");
        dd->errorCode = CUDD_INTERNAL_ERROR;
    }

    size = ALLOC(int, 1);
    if (size == NULL) {
        dd->errorCode = CUDD_MEMORY_OUT;
        return(NULL);
    }
    *size = numNodes;

#ifdef DEBUG
    num_calls = 0;
#endif
    /* table to store nodes being created. */
    storeTable = st_init_table(st_ptrcmp, st_ptrhash);
    /* insert the constant */
    cuddRef(one);
    if (st_insert(storeTable, (char *)Cudd_ReadOne(dd), NIL(char)) ==
        ST_OUT_OF_MEM) {
        fprintf(dd->out, "Something wrong, st_table insert failed\n");
    }
    /* table to store approximations of nodes */
    approxTable = st_init_table(st_ptrcmp, st_ptrhash);
    subset = (DdNode *)BuildSubsetBdd(dd, f, size, visitedTable, threshold,
                                      storeTable, approxTable);
    if (subset != NULL) {
        cuddRef(subset);
    }

    stGen = st_init_gen(approxTable);
    if (stGen == NULL) {
        st_free_table(approxTable);
        return(NULL);
    }
    while(st_gen(stGen, (char **)&key, (char **)&value)) {
        Cudd_RecursiveDeref(dd, (DdNode *)value);
    }
    st_free_gen(stGen); stGen = NULL;
    st_free_table(approxTable);

    stGen = st_init_gen(storeTable);
    if (stGen == NULL) {
        st_free_table(storeTable);
        return(NULL);
    }
    while(st_gen(stGen, (char **)&key, (char **)&value)) {
        Cudd_RecursiveDeref(dd, (DdNode *)key);
    }
    st_free_gen(stGen); stGen = NULL;
    st_free_table(storeTable);

    for (i = 0; i <= page; i++) {
        FREE(mintermPages[i]);
    }
    FREE(mintermPages);
    for (i = 0; i <= page; i++) {
        FREE(nodePages[i]);
    }
    FREE(nodePages);
    for (i = 0; i <= page; i++) {
        FREE(lightNodePages[i]);
    }
    FREE(lightNodePages);
    for (i = 0; i <= nodeDataPage; i++) {
        FREE(nodeDataPages[i]);
    }
    FREE(nodeDataPages);
    st_free_table(visitedTable);
    FREE(size);
#if 0
    (void) Cudd_DebugCheck(dd);
    (void) Cudd_CheckKeys(dd);
#endif

    if (subset != NULL) {
#ifdef DD_DEBUG
      if (!Cudd_bddLeq(dd, subset, f)) {
            fprintf(dd->err, "Wrong subset\n");
            dd->errorCode = CUDD_INTERNAL_ERROR;
            return(NULL);
      }
#endif
        cuddDeref(subset);
        return(subset);
    } else {
        return(NULL);
    }
} /* end of cuddSubsetHeavyBranch */

static void ResizeCountMintermPages

(

void

)

[static]

Function********************************************************************

Synopsis [Resize the number of pages allocated to store the minterm counts. ]

Description [Resize the number of pages allocated to store the minterm counts. The procedure moves the counter to the next page when the end of the page is reached and allocates new pages when necessary.]

SideEffects [Changes the size of minterm pages, page, page index, maximum number of pages freeing stuff in case of memory out. ]

SeeAlso []

Definition at line 529 of file cuddSubsetHB.c.

{
    int i;
    double **newMintermPages;

    page++;
    /* If the current page index is larger than the number of pages
     * allocated, allocate a new page array. Page numbers are incremented by
     * INITIAL_PAGES
     */
    if (page == maxPages) {
        newMintermPages = ALLOC(double *,maxPages + INITIAL_PAGES);
        if (newMintermPages == NULL) {
            for (i = 0; i < page; i++) FREE(mintermPages[i]);
            FREE(mintermPages);
            memOut = 1;
            return;
        } else {
            for (i = 0; i < maxPages; i++) {
                newMintermPages[i] = mintermPages[i];
            }
            /* Increase total page count */
            maxPages += INITIAL_PAGES;
            FREE(mintermPages);
            mintermPages = newMintermPages;
        }
    }
    /* Allocate a new page */
    currentMintermPage = mintermPages[page] = ALLOC(double,pageSize);
    if (currentMintermPage == NULL) {
        for (i = 0; i < page; i++) FREE(mintermPages[i]);
        FREE(mintermPages);
        memOut = 1;
        return;
    }
    /* reset page index */
    pageIndex = 0;
    return;

} /* end of ResizeCountMintermPages */

static void ResizeCountNodePages

(

void

)

[static]

Function********************************************************************

Synopsis [Resize the number of pages allocated to store the node counts.]

Description [Resize the number of pages allocated to store the node counts. The procedure moves the counter to the next page when the end of the page is reached and allocates new pages when necessary.]

SideEffects [Changes the size of pages, page, page index, maximum number of pages freeing stuff in case of memory out.]

SeeAlso []

Definition at line 586 of file cuddSubsetHB.c.

{
    int i;
    int **newNodePages;

    page++;

    /* If the current page index is larger than the number of pages
     * allocated, allocate a new page array. The number of pages is incremented
     * by INITIAL_PAGES.
     */
    if (page == maxPages) {
        newNodePages = ALLOC(int *,maxPages + INITIAL_PAGES);
        if (newNodePages == NULL) {
            for (i = 0; i < page; i++) FREE(nodePages[i]);
            FREE(nodePages);
            for (i = 0; i < page; i++) FREE(lightNodePages[i]);
            FREE(lightNodePages);
            memOut = 1;
            return;
        } else {
            for (i = 0; i < maxPages; i++) {
                newNodePages[i] = nodePages[i];
            }
            FREE(nodePages);
            nodePages = newNodePages;
        }

        newNodePages = ALLOC(int *,maxPages + INITIAL_PAGES);
        if (newNodePages == NULL) {
            for (i = 0; i < page; i++) FREE(nodePages[i]);
            FREE(nodePages);
            for (i = 0; i < page; i++) FREE(lightNodePages[i]);
            FREE(lightNodePages);
            memOut = 1;
            return;
        } else {
            for (i = 0; i < maxPages; i++) {
                newNodePages[i] = lightNodePages[i];
            }
            FREE(lightNodePages);
            lightNodePages = newNodePages;
        }
        /* Increase total page count */
        maxPages += INITIAL_PAGES;
    }
    /* Allocate a new page */
    currentNodePage = nodePages[page] = ALLOC(int,pageSize);
    if (currentNodePage == NULL) {
        for (i = 0; i < page; i++) FREE(nodePages[i]);
        FREE(nodePages);
        for (i = 0; i < page; i++) FREE(lightNodePages[i]);
        FREE(lightNodePages);
        memOut = 1;
        return;
    }
    /* Allocate a new page */
    currentLightNodePage = lightNodePages[page] = ALLOC(int,pageSize);
    if (currentLightNodePage == NULL) {
        for (i = 0; i <= page; i++) FREE(nodePages[i]);
        FREE(nodePages);
        for (i = 0; i < page; i++) FREE(lightNodePages[i]);
        FREE(lightNodePages);
        memOut = 1;
        return;
    }
    /* reset page index */
    pageIndex = 0;
    return;

} /* end of ResizeCountNodePages */

static void ResizeNodeDataPages

(

void

)

[static]

AutomaticStart

Function********************************************************************

Synopsis [Resize the number of pages allocated to store the node data.]

Description [Resize the number of pages allocated to store the node data The procedure moves the counter to the next page when the end of the page is reached and allocates new pages when necessary.]

SideEffects [Changes the size of pages, page, page index, maximum number of pages freeing stuff in case of memory out. ]

SeeAlso []

Definition at line 470 of file cuddSubsetHB.c.

{
    int i;
    NodeData_t **newNodeDataPages;

    nodeDataPage++;
    /* If the current page index is larger than the number of pages
     * allocated, allocate a new page array. Page numbers are incremented by
     * INITIAL_PAGES
     */
    if (nodeDataPage == maxNodeDataPages) {
        newNodeDataPages = ALLOC(NodeData_t *,maxNodeDataPages + INITIAL_PAGES);
        if (newNodeDataPages == NULL) {
            for (i = 0; i < nodeDataPage; i++) FREE(nodeDataPages[i]);
            FREE(nodeDataPages);
            memOut = 1;
            return;
        } else {
            for (i = 0; i < maxNodeDataPages; i++) {
                newNodeDataPages[i] = nodeDataPages[i];
            }
            /* Increase total page count */
            maxNodeDataPages += INITIAL_PAGES;
            FREE(nodeDataPages);
            nodeDataPages = newNodeDataPages;
        }
    }
    /* Allocate a new page */
    currentNodeDataPage = nodeDataPages[nodeDataPage] =
        ALLOC(NodeData_t ,nodeDataPageSize);
    if (currentNodeDataPage == NULL) {
        for (i = 0; i < nodeDataPage; i++) FREE(nodeDataPages[i]);
        FREE(nodeDataPages);
        memOut = 1;
        return;
    }
    /* reset page index */
    nodeDataPageIndex = 0;
    return;

} /* end of ResizeNodeDataPages */

static void StoreNodes	(	st_table *	storeTable,
		DdManager *	dd,
		DdNode *	node
	)			[static]

Function********************************************************************

Synopsis [Procedure to recursively store nodes that are retained in the subset.]

Description [rocedure to recursively store nodes that are retained in the subset.]

SideEffects [None]

SeeAlso [StoreNodes]

Definition at line 1109 of file cuddSubsetHB.c.

{
    DdNode *N, *Nt, *Ne;
    if (Cudd_IsConstant(dd)) {
        return;
    }
    N = Cudd_Regular(node);
    if (st_lookup(storeTable, (char *)N, NIL(char *))) {
        return;
    }
    cuddRef(N);
    if (st_insert(storeTable, (char *)N, NIL(char)) == ST_OUT_OF_MEM) {
        fprintf(dd->err,"Something wrong, st_table insert failed\n");
    }

    Nt = Cudd_T(N);
    Ne = Cudd_E(N);

    StoreNodes(storeTable, dd, Nt);
    StoreNodes(storeTable, dd, Ne);
    return;

}

static st_table * SubsetCountMinterm	(	DdNode *	node,
		int	nvars
	)			[static]

Function********************************************************************

Synopsis [Counts minterms of each node in the DAG]

Description [Counts minterms of each node in the DAG. Similar to the Cudd_CountMinterm procedure except this returns the minterm count for all the nodes in the bdd in an st_table.]

SideEffects [none]

SeeAlso [SubsetCountMintermAux]

Definition at line 787 of file cuddSubsetHB.c.

{
    st_table    *table;
    int i;


#ifdef DEBUG
    num_calls = 0;
#endif

    max = pow(2.0,(double) nvars);
    table = st_init_table(st_ptrcmp,st_ptrhash);
    if (table == NULL) goto OUT_OF_MEM;
    maxPages = INITIAL_PAGES;
    mintermPages = ALLOC(double *,maxPages);
    if (mintermPages == NULL) {
        st_free_table(table);
        goto OUT_OF_MEM;
    }
    page = 0;
    currentMintermPage = ALLOC(double,pageSize);
    mintermPages[page] = currentMintermPage;
    if (currentMintermPage == NULL) {
        FREE(mintermPages);
        st_free_table(table);
        goto OUT_OF_MEM;
    }
    pageIndex = 0;
    maxNodeDataPages = INITIAL_PAGES;
    nodeDataPages = ALLOC(NodeData_t *, maxNodeDataPages);
    if (nodeDataPages == NULL) {
        for (i = 0; i <= page ; i++) FREE(mintermPages[i]);
        FREE(mintermPages);
        st_free_table(table);
        goto OUT_OF_MEM;
    }
    nodeDataPage = 0;
    currentNodeDataPage = ALLOC(NodeData_t ,nodeDataPageSize);
    nodeDataPages[nodeDataPage] = currentNodeDataPage;
    if (currentNodeDataPage == NULL) {
        for (i = 0; i <= page ; i++) FREE(mintermPages[i]);
        FREE(mintermPages);
        FREE(nodeDataPages);
        st_free_table(table);
        goto OUT_OF_MEM;
    }
    nodeDataPageIndex = 0;

    (void) SubsetCountMintermAux(node,max,table);
    if (memOut) goto OUT_OF_MEM;
    return(table);

OUT_OF_MEM:
    memOut = 1;
    return(NULL);

} /* end of SubsetCountMinterm */

static double SubsetCountMintermAux	(	DdNode *	node,
		double	max,
		st_table *	table
	)			[static]

Function********************************************************************

Synopsis [Recursively counts minterms of each node in the DAG.]

Description [Recursively counts minterms of each node in the DAG. Similar to the cuddCountMintermAux which recursively counts the number of minterms for the dag rooted at each node in terms of the total number of variables (max). This procedure creates the node data structure and stores the minterm count as part of the node data structure. ]

SideEffects [Creates structures of type node quality and fills the st_table]

SeeAlso [SubsetCountMinterm]

Definition at line 676 of file cuddSubsetHB.c.

{

    DdNode      *N,*Nv,*Nnv; /* nodes to store cofactors  */
    double      min,*pmin; /* minterm count */
    double      min1, min2; /* minterm count */
    NodeData_t *dummy;
    NodeData_t *newEntry;
    int i;

#ifdef DEBUG
    num_calls++;
#endif

    /* Constant case */
    if (Cudd_IsConstant(node)) {
        if (node == zero) {
            return(0.0);
        } else {
            return(max);
        }
    } else {

        /* check if entry for this node exists */
        if (st_lookup(table, node, &dummy)) {
            min = *(dummy->mintermPointer);
            return(min);
        }

        /* Make the node regular to extract cofactors */
        N = Cudd_Regular(node);

        /* store the cofactors */
        Nv = Cudd_T(N);
        Nnv = Cudd_E(N);

        Nv = Cudd_NotCond(Nv, Cudd_IsComplement(node));
        Nnv = Cudd_NotCond(Nnv, Cudd_IsComplement(node));

        min1 =  SubsetCountMintermAux(Nv, max,table)/2.0;
        if (memOut) return(0.0);
        min2 =  SubsetCountMintermAux(Nnv,max,table)/2.0;
        if (memOut) return(0.0);
        min = (min1+min2);

        /* if page index is at the bottom, then create a new page */
        if (pageIndex == pageSize) ResizeCountMintermPages();
        if (memOut) {
            for (i = 0; i <= nodeDataPage; i++) FREE(nodeDataPages[i]);
            FREE(nodeDataPages);
            st_free_table(table);
            return(0.0);
        }

        /* point to the correct location in the page */
        pmin = currentMintermPage+pageIndex;
        pageIndex++;

        /* store the minterm count of this node in the page */
        *pmin = min;

        /* Note I allocate the struct here. Freeing taken care of later */
        if (nodeDataPageIndex == nodeDataPageSize) ResizeNodeDataPages();
        if (memOut) {
            for (i = 0; i <= page; i++) FREE(mintermPages[i]);
            FREE(mintermPages);
            st_free_table(table);
            return(0.0);
        }

        newEntry = currentNodeDataPage + nodeDataPageIndex;
        nodeDataPageIndex++;

        /* points to the correct location in the page */
        newEntry->mintermPointer = pmin;
        /* initialize this field of the Node Quality structure */
        newEntry->nodesPointer = NULL;

        /* insert entry for the node in the table */
        if (st_insert(table,(char *)node, (char *)newEntry) == ST_OUT_OF_MEM) {
            memOut = 1;
            for (i = 0; i <= page; i++) FREE(mintermPages[i]);
            FREE(mintermPages);
            for (i = 0; i <= nodeDataPage; i++) FREE(nodeDataPages[i]);
            FREE(nodeDataPages);
            st_free_table(table);
            return(0.0);
        }
        return(min);
    }

} /* end of SubsetCountMintermAux */

static int SubsetCountNodes	(	DdNode *	node,
		st_table *	table,
		int	nvars
	)			[static]

Function********************************************************************

Synopsis [Counts the nodes under the current node and its lighter child]

Description [Counts the nodes under the current node and its lighter child. Calls a recursive procedure to count the number of nodes of a DAG rooted at a particular node and the number of nodes taken by its lighter child.]

SideEffects [None]

SeeAlso [SubsetCountNodesAux]

Definition at line 1032 of file cuddSubsetHB.c.

{
    int num;
    int i;

#ifdef DEBUG
    num_calls = 0;
#endif

    max = pow(2.0,(double) nvars);
    maxPages = INITIAL_PAGES;
    nodePages = ALLOC(int *,maxPages);
    if (nodePages == NULL)  {
        goto OUT_OF_MEM;
    }

    lightNodePages = ALLOC(int *,maxPages);
    if (lightNodePages == NULL) {
        for (i = 0; i <= page; i++) FREE(mintermPages[i]);
        FREE(mintermPages);
        for (i = 0; i <= nodeDataPage; i++) FREE(nodeDataPages[i]);
        FREE(nodeDataPages);
        FREE(nodePages);
        goto OUT_OF_MEM;
    }

    page = 0;
    currentNodePage = nodePages[page] = ALLOC(int,pageSize);
    if (currentNodePage == NULL) {
        for (i = 0; i <= page; i++) FREE(mintermPages[i]);
        FREE(mintermPages);
        for (i = 0; i <= nodeDataPage; i++) FREE(nodeDataPages[i]);
        FREE(nodeDataPages);
        FREE(lightNodePages);
        FREE(nodePages);
        goto OUT_OF_MEM;
    }

    currentLightNodePage = lightNodePages[page] = ALLOC(int,pageSize);
    if (currentLightNodePage == NULL) {
        for (i = 0; i <= page; i++) FREE(mintermPages[i]);
        FREE(mintermPages);
        for (i = 0; i <= nodeDataPage; i++) FREE(nodeDataPages[i]);
        FREE(nodeDataPages);
        FREE(currentNodePage);
        FREE(lightNodePages);
        FREE(nodePages);
        goto OUT_OF_MEM;
    }

    pageIndex = 0;
    num = SubsetCountNodesAux(node,table,max);
    if (memOut) goto OUT_OF_MEM;
    return(num);

OUT_OF_MEM:
    memOut = 1;
    return(0);

} /* end of SubsetCountNodes */

static int SubsetCountNodesAux	(	DdNode *	node,
		st_table *	table,
		double	max
	)			[static]

Function********************************************************************

Synopsis [Recursively counts the number of nodes under the dag. Also counts the number of nodes under the lighter child of this node.]

Description [Recursively counts the number of nodes under the dag. Also counts the number of nodes under the lighter child of this node. . Note that the same dag may be the lighter child of two different nodes and have different counts. As with the minterm counts, the node counts are stored in pages to be space efficient and the address for these node counts are stored in an st_table associated to each node. ]

SideEffects [Updates the node data table with node counts]

SeeAlso [SubsetCountNodes]

Definition at line 868 of file cuddSubsetHB.c.

{
    int tval, eval, i;
    DdNode *N, *Nv, *Nnv;
    double minNv, minNnv;
    NodeData_t *dummyN, *dummyNv, *dummyNnv, *dummyNBar;
    int *pmin, *pminBar, *val;

    if ((node == NULL) || Cudd_IsConstant(node))
        return(0);

    /* if this node has been processed do nothing */
    if (st_lookup(table, node, &dummyN) == 1) {
        val = dummyN->nodesPointer;
        if (val != NULL)
            return(0);
    } else {
        return(0);
    }

    N  = Cudd_Regular(node);
    Nv = Cudd_T(N);
    Nnv = Cudd_E(N);

    Nv = Cudd_NotCond(Nv, Cudd_IsComplement(node));
    Nnv = Cudd_NotCond(Nnv, Cudd_IsComplement(node));

    /* find the minterm counts for the THEN and ELSE branches */
    if (Cudd_IsConstant(Nv)) {
        if (Nv == zero) {
            minNv = 0.0;
        } else {
            minNv = max;
        }
    } else {
        if (st_lookup(table, Nv, &dummyNv) == 1)
            minNv = *(dummyNv->mintermPointer);
        else {
            return(0);
        }
    }
    if (Cudd_IsConstant(Nnv)) {
        if (Nnv == zero) {
            minNnv = 0.0;
        } else {
            minNnv = max;
        }
    } else {
        if (st_lookup(table, Nnv, &dummyNnv) == 1) {
            minNnv = *(dummyNnv->mintermPointer);
        }
        else {
            return(0);
        }
    }


    /* recur based on which has larger minterm, */
    if (minNv >= minNnv) {
        tval = SubsetCountNodesAux(Nv, table, max);
        if (memOut) return(0);
        eval = SubsetCountNodesAux(Nnv, table, max);
        if (memOut) return(0);

        /* store the node count of the lighter child. */
        if (pageIndex == pageSize) ResizeCountNodePages();
        if (memOut) {
            for (i = 0; i <= page; i++) FREE(mintermPages[i]);
            FREE(mintermPages);
            for (i = 0; i <= nodeDataPage; i++) FREE(nodeDataPages[i]);
            FREE(nodeDataPages);
            st_free_table(table);
            return(0);
        }
        pmin = currentLightNodePage + pageIndex;
        *pmin = eval; /* Here the ELSE child is lighter */
        dummyN->lightChildNodesPointer = pmin;

    } else {
        eval = SubsetCountNodesAux(Nnv, table, max);
        if (memOut) return(0);
        tval = SubsetCountNodesAux(Nv, table, max);
        if (memOut) return(0);

        /* store the node count of the lighter child. */
        if (pageIndex == pageSize) ResizeCountNodePages();
        if (memOut) {
            for (i = 0; i <= page; i++) FREE(mintermPages[i]);
            FREE(mintermPages);
            for (i = 0; i <= nodeDataPage; i++) FREE(nodeDataPages[i]);
            FREE(nodeDataPages);
            st_free_table(table);
            return(0);
        }
        pmin = currentLightNodePage + pageIndex;
        *pmin = tval; /* Here the THEN child is lighter */
        dummyN->lightChildNodesPointer = pmin;

    }
    /* updating the page index for node count storage. */
    pmin = currentNodePage + pageIndex;
    *pmin = tval + eval + 1;
    dummyN->nodesPointer = pmin;

    /* pageIndex is parallel page index for count_nodes and count_lightNodes */
    pageIndex++;

    /* if this node has been reached first, it belongs to a heavier
       branch. Its complement will be reached later on a lighter branch.
       Hence the complement has zero node count. */

    if (st_lookup(table, Cudd_Not(node), &dummyNBar) == 1)  {
        if (pageIndex == pageSize) ResizeCountNodePages();
        if (memOut) {
            for (i = 0; i < page; i++) FREE(mintermPages[i]);
            FREE(mintermPages);
            for (i = 0; i < nodeDataPage; i++) FREE(nodeDataPages[i]);
            FREE(nodeDataPages);
            st_free_table(table);
            return(0);
        }
        pminBar = currentLightNodePage + pageIndex;
        *pminBar = 0;
        dummyNBar->lightChildNodesPointer = pminBar;
        /* The lighter child has less nodes than the parent.
         * So if parent 0 then lighter child zero
         */
        if (pageIndex == pageSize) ResizeCountNodePages();
        if (memOut) {
            for (i = 0; i < page; i++) FREE(mintermPages[i]);
            FREE(mintermPages);
            for (i = 0; i < nodeDataPage; i++) FREE(nodeDataPages[i]);
            FREE(nodeDataPages);
            st_free_table(table);
            return(0);
        }
        pminBar = currentNodePage + pageIndex;
        *pminBar = 0;
        dummyNBar->nodesPointer = pminBar ; /* maybe should point to zero */

        pageIndex++;
    }
    return(*pmin);
} /*end of SubsetCountNodesAux */

---

Variable Documentation

int* currentLightNodePage [static]

Definition at line 135 of file cuddSubsetHB.c.

double* currentMintermPage [static]

Definition at line 128 of file cuddSubsetHB.c.

NodeData_t* currentNodeDataPage [static]

Definition at line 142 of file cuddSubsetHB.c.

int* currentNodePage [static]

Definition at line 133 of file cuddSubsetHB.c.

char rcsid [] DD_UNUSED = "$Id: cuddSubsetHB.c,v 1.37 2009/02/20 02:14:58 fabio Exp $" [static]

Definition at line 116 of file cuddSubsetHB.c.

int** lightNodePages [static]

Definition at line 127 of file cuddSubsetHB.c.

double max [static]

Definition at line 130 of file cuddSubsetHB.c.

int maxNodeDataPages [static]

Definition at line 149 of file cuddSubsetHB.c.

int maxPages [static]

Definition at line 140 of file cuddSubsetHB.c.

int memOut [static]

Definition at line 119 of file cuddSubsetHB.c.

double** mintermPages [static]

Definition at line 125 of file cuddSubsetHB.c.

int nodeDataPage [static]

Definition at line 144 of file cuddSubsetHB.c.

int nodeDataPageIndex [static]

Definition at line 145 of file cuddSubsetHB.c.

NodeData_t** nodeDataPages [static]

Definition at line 146 of file cuddSubsetHB.c.

int nodeDataPageSize = DEFAULT_NODE_DATA_PAGE_SIZE [static]

Definition at line 147 of file cuddSubsetHB.c.

int** nodePages [static]

Definition at line 126 of file cuddSubsetHB.c.

DdNode * one [static]

Definition at line 124 of file cuddSubsetHB.c.

int page [static]

Definition at line 138 of file cuddSubsetHB.c.

int pageIndex [static]

Definition at line 137 of file cuddSubsetHB.c.

int pageSize = DEFAULT_PAGE_SIZE [static]

Definition at line 139 of file cuddSubsetHB.c.

DdNode* zero [static]

Definition at line 124 of file cuddSubsetHB.c.