fsg_lextree.h

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/*
 * fsg_lextree.h -- The collection of all the lextrees for the entire FSM.
 *
 */

#ifndef __S2_FSG_LEXTREE_H__
#define __S2_FSG_LEXTREE_H__

/* SphinxBase headers. */
#include <sphinxbase/cmd_ln.h>
#include <sphinxbase/fsg_model.h>

/* Local headers. */
#include "hmm.h"
#include "dict.h"
#include "dict2pid.h"

/*
 * Compile-time constant determining the size of the
 * bitvector fsg_pnode_t.fsg_pnode_ctxt_t.bv.  (See below.)
 * But it makes memory allocation simpler and more efficient.
 * Make it smaller (2) to save memory if your phoneset has less than
 * 64 phones.
 */
#define FSG_PNODE_CTXT_BVSZ     4

typedef struct {
    uint32 bv[FSG_PNODE_CTXT_BVSZ];
} fsg_pnode_ctxt_t;


/*
 * All transitions (words) out of any given FSG state represented are by a
 * phonetic prefix lextree (except for epsilon or null transitions; they
 * are not part of the lextree).  Lextree leaf nodes represent individual
 * FSG transitions, so no sharing is allowed at the leaf nodes.  The FSG
 * transition probs are distributed along the lextree: the prob at a node
 * is the max of the probs of all leaf nodes (and, hence, FSG transitions)
 * reachable from that node.
 * 
 * To conserve memory, the underlying HMMs with state-level information are
 * allocated only as needed.  Root and leaf nodes must also account for all
 * the possible phonetic contexts, with an independent HMM for each distinct
 * context.
 */
typedef struct fsg_pnode_s {
    /*
     * If this is not a leaf node, the first successor (child) node.  Otherwise
     * the parent FSG transition for which this is the leaf node (for figuring
     * the FSG destination state, and word emitted by the transition).  A node
     * may have several children.  The succ ptr gives just the first; the rest
     * are linked via the sibling ptr below.
     */
    union {
        struct fsg_pnode_s *succ;
        fsg_link_t *fsglink;
    } next;
  
    /*
     * For simplicity of memory management (i.e., freeing the pnodes), all
     * pnodes allocated for all transitions out of a state are maintained in a
     * linear linked list through the alloc_next pointer.
     */
    struct fsg_pnode_s *alloc_next;
  
    /*
     * The next node that is also a child of the parent of this node; NULL if
     * none.
     */
    struct fsg_pnode_s *sibling;

    /*
     * The transition (log) probability to be incurred upon transitioning to
     * this node.  (Transition probabilities are really associated with the
     * transitions.  But a lextree node has exactly one incoming transition.
     * Hence, the prob can be associated with the node.)
     * This is a logs2(prob) value, and includes the language weight.
     */
    int32 logs2prob;
  
    /*
     * The root and leaf positions associated with any transition have to deal
     * with multiple phonetic contexts.  However, different contexts may result
     * in the same SSID (senone-seq ID), and can share a single pnode with that
     * SSID.  But the pnode should track the set of context CI phones that share
     * it.  Hence the fsg_pnode_ctxt_t bit-vector set-representation.  (For
     * simplicity of implementation, its size is a compile-time constant for
     * now.)  Single phone words would need a 2-D array of context, but that's
     * too expensive.  For now, they simply use SIL as right context, so only
     * the left context is properly modelled.
     * (For word-internal phones, this field is unused, of course.)
     */
    fsg_pnode_ctxt_t ctxt;
  
    uint16 ci_ext;      /* This node's CIphone as viewed externally (context) */
    uint8 ppos; /* Phoneme position in pronunciation */
    uint8 leaf; /* Whether this is a leaf node */
  
    /* HMM-state-level stuff here */
    hmm_context_t *ctx;
    hmm_t hmm;
} fsg_pnode_t;

/* Access macros */
#define fsg_pnode_leaf(p)       ((p)->leaf)
#define fsg_pnode_logs2prob(p)  ((p)->logs2prob)
#define fsg_pnode_succ(p)       ((p)->next.succ)
#define fsg_pnode_fsglink(p)    ((p)->next.fsglink)
#define fsg_pnode_sibling(p)    ((p)->sibling)
#define fsg_pnode_hmmptr(p)     (&((p)->hmm))
#define fsg_pnode_ci_ext(p)     ((p)->ci_ext)
#define fsg_pnode_ppos(p)       ((p)->ppos)
#define fsg_pnode_leaf(p)       ((p)->leaf)
#define fsg_pnode_ctxt(p)       ((p)->ctxt)

#define fsg_pnode_add_ctxt(p,c) ((p)->ctxt.bv[(c)>>5] |= (1 << ((c)&0x001f)))

/*
 * The following is macroized because its called very frequently
 * ::: uint32 fsg_pnode_ctxt_sub (fsg_pnode_ctxt_t *src, fsg_pnode_ctxt_t *sub);
 */
/*
 * Subtract bitvector sub from bitvector src (src updated with the result).
 * Return 0 if result is all 0, non-zero otherwise.
 */

#if (FSG_PNODE_CTXT_BVSZ == 1)
    #define FSG_PNODE_CTXT_SUB(src,sub) \
    ((src)->bv[0] = (~((sub)->bv[0]) & (src)->bv[0]))
#elif (FSG_PNODE_CTXT_BVSZ == 2)
    #define FSG_PNODE_CTXT_SUB(src,sub) \
    (((src)->bv[0] = (~((sub)->bv[0]) & (src)->bv[0])) | \
     ((src)->bv[1] = (~((sub)->bv[1]) & (src)->bv[1])))
#elif (FSG_PNODE_CTXT_BVSZ == 4)
    #define FSG_PNODE_CTXT_SUB(src,sub) \
    (((src)->bv[0] = (~((sub)->bv[0]) & (src)->bv[0]))  | \
     ((src)->bv[1] = (~((sub)->bv[1]) & (src)->bv[1]))  | \
     ((src)->bv[2] = (~((sub)->bv[2]) & (src)->bv[2]))  | \
     ((src)->bv[3] = (~((sub)->bv[3]) & (src)->bv[3])))
#else
    #define FSG_PNODE_CTXT_SUB(src,sub) fsg_pnode_ctxt_sub_generic((src),(sub))
#endif

typedef struct fsg_lextree_s {
    fsg_model_t *fsg;   
    hmm_context_t *ctx; 
    dict_t *dict;     
    dict2pid_t *d2p;    
    bin_mdef_t *mdef;   
    /*
     * Left and right CIphone sets for each state.
     * Left context CIphones for a state S: If word W transitions into S, W's
     * final CIphone is in S's {lc}.  Words transitioning out of S must consider
     * these left context CIphones.
     * Similarly, right contexts for state S: If word W transitions out of S,
     * W's first CIphone is in S's {rc}.  Words transitioning into S must consider
     * these right contexts.
     * 
     * NOTE: Words may transition into and out of S INDIRECTLY, with intermediate
     *   null transitions.
     * NOTE: Single-phone words are difficult; only SILENCE right context is
     *   modelled for them.
     * NOTE: Non-silence filler phones aren't included in these sets.  Filler
     *   words don't use context, and present the SILENCE phone as context to
     *   adjacent words.
     */
    int16 **lc;         
    int16 **rc;         
    fsg_pnode_t **root; /* root[s] = lextree representing all transitions
                           out of state s.  Note that the "tree" for each
                           state is actually a collection of trees, linked
                           via fsg_pnode_t.sibling (root[s]->sibling) */
    fsg_pnode_t **alloc_head;   /* alloc_head[s] = head of linear list of all
                                   pnodes allocated for state s */
    int32 n_pnode;      /* #HMM nodes in search structure */
    int32 wip;
    int32 pip;
} fsg_lextree_t;

/* Access macros */
#define fsg_lextree_root(lt,s)  ((lt)->root[s])
#define fsg_lextree_n_pnode(lt) ((lt)->n_pnode)

fsg_lextree_t *fsg_lextree_init(fsg_model_t *fsg, dict_t *dict,
                                dict2pid_t *d2p,
                                bin_mdef_t *mdef, hmm_context_t *ctx,
                                int32 wip, int32 pip);

void fsg_lextree_free(fsg_lextree_t *fsg);

void fsg_lextree_dump(fsg_lextree_t *fsg, FILE *fh);

void fsg_psubtree_pnode_deactivate(fsg_pnode_t *pnode);

void fsg_pnode_add_all_ctxt(fsg_pnode_ctxt_t *ctxt);

uint32 fsg_pnode_ctxt_sub_generic(fsg_pnode_ctxt_t *src, fsg_pnode_ctxt_t *sub);

#endif