Merge remote-tracking branch 'origin/redwood' into release

1 files changed, 0 insertions, 962 deletions

diff --git a/media/pocketsphinx/src/ngram_search_fwdflat.c b/media/pocketsphinx/src/ngram_search_fwdflat.c
deleted file mode 100644
index 02becdc85..000000000
--- a/media/pocketsphinx/src/ngram_search_fwdflat.c
+++ /dev/null
@@ -1,962 +0,0 @@
-/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
-/* ====================================================================
- * Copyright (c) 2008 Carnegie Mellon University.  All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer. 
- *
- * 2. 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.
- *
- * This work was supported in part by funding from the Defense Advanced 
- * Research Projects Agency and the National Science Foundation of the 
- * United States of America, and the CMU Sphinx Speech Consortium.
- *
- * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND 
- * ANY EXPRESSED 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 CARNEGIE MELLON UNIVERSITY
- * NOR ITS EMPLOYEES 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.
- *
- * ====================================================================
- *
- */
-
-/**
- * @file ngram_search_fwdflat.c Flat lexicon search.
- */
-
-/* System headers. */
-#include <string.h>
-#include <assert.h>
-
-/* SphinxBase headers. */
-#include <sphinxbase/ckd_alloc.h>
-#include <sphinxbase/listelem_alloc.h>
-#include <sphinxbase/err.h>
-
-/* Local headers. */
-#include "ngram_search.h"
-#include "ps_lattice_internal.h"
-
-/* Turn this on to dump channels for debugging */
-#define __CHAN_DUMP__		0
-#if __CHAN_DUMP__
-#define chan_v_eval(chan) hmm_dump_vit_eval(&(chan)->hmm, stderr)
-#else
-#define chan_v_eval(chan) hmm_vit_eval(&(chan)->hmm)
-#endif
-
-static void
-ngram_fwdflat_expand_all(ngram_search_t *ngs)
-{
-    int n_words, i;
-
-    /* For all "real words" (not fillers or <s>/</s>) in the dictionary,
-     *
-     * 1) Add the ones which are in the LM to the fwdflat wordlist
-     * 2) And to the expansion list (since we are expanding all)
-     */
-    ngs->n_expand_words = 0;
-    n_words = ps_search_n_words(ngs);
-    bitvec_clear_all(ngs->expand_word_flag, ps_search_n_words(ngs));
-    for (i = 0; i < n_words; ++i) {
-        if (!ngram_model_set_known_wid(ngs->lmset,
-                                       dict_basewid(ps_search_dict(ngs),i)))
-            continue;
-        ngs->fwdflat_wordlist[ngs->n_expand_words] = i;
-        ngs->expand_word_list[ngs->n_expand_words] = i;
-        bitvec_set(ngs->expand_word_flag, i);
-        ngs->n_expand_words++;
-    }
-    E_INFO("Utterance vocabulary contains %d words\n", ngs->n_expand_words);
-    ngs->expand_word_list[ngs->n_expand_words] = -1;
-    ngs->fwdflat_wordlist[ngs->n_expand_words] = -1;
-}
-
-static void
-ngram_fwdflat_allocate_1ph(ngram_search_t *ngs)
-{
-    dict_t *dict = ps_search_dict(ngs);
-    int n_words = ps_search_n_words(ngs);
-    int i, w;
-
-    /* Allocate single-phone words, since they won't have
-     * been allocated for us by fwdtree initialization. */
-    ngs->n_1ph_words = 0;
-    for (w = 0; w < n_words; w++) {
-        if (dict_is_single_phone(dict, w))
-            ++ngs->n_1ph_words;
-    }
-    ngs->single_phone_wid = ckd_calloc(ngs->n_1ph_words,
-                                       sizeof(*ngs->single_phone_wid));
-    ngs->rhmm_1ph = ckd_calloc(ngs->n_1ph_words, sizeof(*ngs->rhmm_1ph));
-    i = 0;
-    for (w = 0; w < n_words; w++) {
-        if (!dict_is_single_phone(dict, w))
-            continue;
-
-        /* DICT2PID location */
-        ngs->rhmm_1ph[i].ciphone = dict_first_phone(dict, w);
-        ngs->rhmm_1ph[i].ci2phone = bin_mdef_silphone(ps_search_acmod(ngs)->mdef);
-        hmm_init(ngs->hmmctx, &ngs->rhmm_1ph[i].hmm, TRUE,
-                 /* ssid */ bin_mdef_pid2ssid(ps_search_acmod(ngs)->mdef,
-                                              ngs->rhmm_1ph[i].ciphone),
-                 /* tmatid */ bin_mdef_pid2tmatid(ps_search_acmod(ngs)->mdef,
-    						  ngs->rhmm_1ph[i].ciphone));
-        ngs->rhmm_1ph[i].next = NULL;
-        ngs->word_chan[w] = (chan_t *) &(ngs->rhmm_1ph[i]);
-        ngs->single_phone_wid[i] = w;
-        i++;
-    }
-}
-
-static void
-ngram_fwdflat_free_1ph(ngram_search_t *ngs)
-{
-    int i, w;
-    int n_words = ps_search_n_words(ngs);
-
-    for (i = w = 0; w < n_words; ++w) {
-        if (!dict_is_single_phone(ps_search_dict(ngs), w))
-            continue;
-        hmm_deinit(&ngs->rhmm_1ph[i].hmm);
-        ++i;
-    }
-    ckd_free(ngs->rhmm_1ph);
-    ngs->rhmm_1ph = NULL;
-    ckd_free(ngs->single_phone_wid);
-}
-
-void
-ngram_fwdflat_init(ngram_search_t *ngs)
-{
-    int n_words;
-
-    n_words = ps_search_n_words(ngs);
-    ngs->fwdflat_wordlist = ckd_calloc(n_words + 1, sizeof(*ngs->fwdflat_wordlist));
-    ngs->expand_word_flag = bitvec_alloc(n_words);
-    ngs->expand_word_list = ckd_calloc(n_words + 1, sizeof(*ngs->expand_word_list));
-    ngs->frm_wordlist = ckd_calloc(ngs->n_frame_alloc, sizeof(*ngs->frm_wordlist));
-    ngs->min_ef_width = cmd_ln_int32_r(ps_search_config(ngs), "-fwdflatefwid");
-    ngs->max_sf_win = cmd_ln_int32_r(ps_search_config(ngs), "-fwdflatsfwin");
-    E_INFO("fwdflat: min_ef_width = %d, max_sf_win = %d\n",
-           ngs->min_ef_width, ngs->max_sf_win);
-
-    /* No tree-search; pre-build the expansion list, including all LM words. */
-    if (!ngs->fwdtree) {
-        /* Build full expansion list from LM words. */
-        ngram_fwdflat_expand_all(ngs);
-        /* Allocate single phone words. */
-        ngram_fwdflat_allocate_1ph(ngs);
-    }
-}
-
-void
-ngram_fwdflat_deinit(ngram_search_t *ngs)
-{
-    double n_speech = (double)ngs->n_tot_frame
-            / cmd_ln_int32_r(ps_search_config(ngs), "-frate");
-
-    E_INFO("TOTAL fwdflat %.2f CPU %.3f xRT\n",
-           ngs->fwdflat_perf.t_tot_cpu,
-           ngs->fwdflat_perf.t_tot_cpu / n_speech);
-    E_INFO("TOTAL fwdflat %.2f wall %.3f xRT\n",
-           ngs->fwdflat_perf.t_tot_elapsed,
-           ngs->fwdflat_perf.t_tot_elapsed / n_speech);
-
-    /* Free single-phone words if we allocated them. */
-    if (!ngs->fwdtree) {
-        ngram_fwdflat_free_1ph(ngs);
-    }
-    ckd_free(ngs->fwdflat_wordlist);
-    bitvec_free(ngs->expand_word_flag);
-    ckd_free(ngs->expand_word_list);
-    ckd_free(ngs->frm_wordlist);
-}
-
-int
-ngram_fwdflat_reinit(ngram_search_t *ngs)
-{
-    /* Reallocate things that depend on the number of words. */
-    int n_words;
-
-    ckd_free(ngs->fwdflat_wordlist);
-    ckd_free(ngs->expand_word_list);
-    bitvec_free(ngs->expand_word_flag);
-    n_words = ps_search_n_words(ngs);
-    ngs->fwdflat_wordlist = ckd_calloc(n_words + 1, sizeof(*ngs->fwdflat_wordlist));
-    ngs->expand_word_flag = bitvec_alloc(n_words);
-    ngs->expand_word_list = ckd_calloc(n_words + 1, sizeof(*ngs->expand_word_list));
-    
-    /* No tree-search; take care of the expansion list and single phone words. */
-    if (!ngs->fwdtree) {
-        /* Free single-phone words. */
-        ngram_fwdflat_free_1ph(ngs);
-        /* Reallocate word_chan. */
-        ckd_free(ngs->word_chan);
-        ngs->word_chan = ckd_calloc(dict_size(ps_search_dict(ngs)),
-                                    sizeof(*ngs->word_chan));
-        /* Rebuild full expansion list from LM words. */
-        ngram_fwdflat_expand_all(ngs);
-        /* Allocate single phone words. */
-        ngram_fwdflat_allocate_1ph(ngs);
-    }
-    /* Otherwise there is nothing to do since the wordlist is
-     * generated anew every utterance. */
-    return 0;
-}
-
-/**
- * Find all active words in backpointer table and sort by frame.
- */
-static void
-build_fwdflat_wordlist(ngram_search_t *ngs)
-{
-    int32 i, f, sf, ef, wid, nwd;
-    bptbl_t *bp;
-    ps_latnode_t *node, *prevnode, *nextnode;
-
-    /* No tree-search, use statically allocated wordlist. */
-    if (!ngs->fwdtree)
-        return;
-
-    memset(ngs->frm_wordlist, 0, ngs->n_frame_alloc * sizeof(*ngs->frm_wordlist));
-
-    /* Scan the backpointer table for all active words and record
-     * their exit frames. */
-    for (i = 0, bp = ngs->bp_table; i < ngs->bpidx; i++, bp++) {
-        sf = (bp->bp < 0) ? 0 : ngs->bp_table[bp->bp].frame + 1;
-        ef = bp->frame;
-        wid = bp->wid;
-
-        /* Anything that can be transitioned to in the LM can go in
-         * the word list. */
-        if (!ngram_model_set_known_wid(ngs->lmset,
-                                       dict_basewid(ps_search_dict(ngs), wid)))
-            continue;
-
-        /* Look for it in the wordlist. */
-        for (node = ngs->frm_wordlist[sf]; node && (node->wid != wid);
-             node = node->next);
-
-        /* Update last end frame. */
-        if (node)
-            node->lef = ef;
-        else {
-            /* New node; link to head of list */
-            node = listelem_malloc(ngs->latnode_alloc);
-            node->wid = wid;
-            node->fef = node->lef = ef;
-
-            node->next = ngs->frm_wordlist[sf];
-            ngs->frm_wordlist[sf] = node;
-        }
-    }
-
-    /* Eliminate "unlikely" words, for which there are too few end points */
-    for (f = 0; f < ngs->n_frame; f++) {
-        prevnode = NULL;
-        for (node = ngs->frm_wordlist[f]; node; node = nextnode) {
-            nextnode = node->next;
-            /* Word has too few endpoints */
-            if ((node->lef - node->fef < ngs->min_ef_width) ||
-                /* Word is </s> and doesn't actually end in last frame */
-                ((node->wid == ps_search_finish_wid(ngs)) && (node->lef < ngs->n_frame - 1))) {
-                if (!prevnode)
-                    ngs->frm_wordlist[f] = nextnode;
-                else
-                    prevnode->next = nextnode;
-                listelem_free(ngs->latnode_alloc, node);
-            }
-            else
-                prevnode = node;
-        }
-    }
-
-    /* Form overall wordlist for 2nd pass */
-    nwd = 0;
-    bitvec_clear_all(ngs->word_active, ps_search_n_words(ngs));
-    for (f = 0; f < ngs->n_frame; f++) {
-        for (node = ngs->frm_wordlist[f]; node; node = node->next) {
-            if (!bitvec_is_set(ngs->word_active, node->wid)) {
-                bitvec_set(ngs->word_active, node->wid);
-                ngs->fwdflat_wordlist[nwd++] = node->wid;
-            }
-        }
-    }
-    ngs->fwdflat_wordlist[nwd] = -1;
-    E_INFO("Utterance vocabulary contains %d words\n", nwd);
-}
-
-/**
- * Build HMM network for one utterance of fwdflat search.
- */
-static void
-build_fwdflat_chan(ngram_search_t *ngs)
-{
-    int32 i, wid, p;
-    root_chan_t *rhmm;
-    chan_t *hmm, *prevhmm;
-    dict_t *dict;
-    dict2pid_t *d2p;
-
-    dict = ps_search_dict(ngs);
-    d2p = ps_search_dict2pid(ngs);
-
-    /* Build word HMMs for each word in the lattice. */
-    for (i = 0; ngs->fwdflat_wordlist[i] >= 0; i++) {
-        wid = ngs->fwdflat_wordlist[i];
-
-        /* Single-phone words are permanently allocated */
-        if (dict_is_single_phone(dict, wid))
-            continue;
-
-        assert(ngs->word_chan[wid] == NULL);
-
-        /* Multiplex root HMM for first phone (one root per word, flat
-         * lexicon).  diphone is irrelevant here, for the time being,
-         * at least. */
-        rhmm = listelem_malloc(ngs->root_chan_alloc);
-        rhmm->ci2phone = dict_second_phone(dict, wid);
-        rhmm->ciphone = dict_first_phone(dict, wid);
-        rhmm->next = NULL;
-        hmm_init(ngs->hmmctx, &rhmm->hmm, TRUE,
-                 bin_mdef_pid2ssid(ps_search_acmod(ngs)->mdef, rhmm->ciphone),
-                 bin_mdef_pid2tmatid(ps_search_acmod(ngs)->mdef, rhmm->ciphone));
-
-        /* HMMs for word-internal phones */
-        prevhmm = NULL;
-        for (p = 1; p < dict_pronlen(dict, wid) - 1; p++) {
-            hmm = listelem_malloc(ngs->chan_alloc);
-            hmm->ciphone = dict_pron(dict, wid, p);
-            hmm->info.rc_id = (p == dict_pronlen(dict, wid) - 1) ? 0 : -1;
-            hmm->next = NULL;
-            hmm_init(ngs->hmmctx, &hmm->hmm, FALSE,
-                     dict2pid_internal(d2p,wid,p), 
-		     bin_mdef_pid2tmatid(ps_search_acmod(ngs)->mdef, hmm->ciphone));
-
-            if (prevhmm)
-                prevhmm->next = hmm;
-            else
-                rhmm->next = hmm;
-
-            prevhmm = hmm;
-        }
-
-        /* Right-context phones */
-        ngram_search_alloc_all_rc(ngs, wid);
-
-        /* Link in just allocated right-context phones */
-        if (prevhmm)
-            prevhmm->next = ngs->word_chan[wid];
-        else
-            rhmm->next = ngs->word_chan[wid];
-        ngs->word_chan[wid] = (chan_t *) rhmm;
-    }
-
-}
-
-void
-ngram_fwdflat_start(ngram_search_t *ngs)
-{
-    root_chan_t *rhmm;
-    int i;
-
-    ptmr_reset(&ngs->fwdflat_perf);
-    ptmr_start(&ngs->fwdflat_perf);
-    build_fwdflat_wordlist(ngs);
-    build_fwdflat_chan(ngs);
-
-    ngs->bpidx = 0;
-    ngs->bss_head = 0;
-
-    for (i = 0; i < ps_search_n_words(ngs); i++)
-        ngs->word_lat_idx[i] = NO_BP;
-
-    /* Reset the permanently allocated single-phone words, since they
-     * may have junk left over in them from previous searches. */
-    for (i = 0; i < ngs->n_1ph_words; i++) {
-        int32 w = ngs->single_phone_wid[i];
-        rhmm = (root_chan_t *) ngs->word_chan[w];
-        hmm_clear(&rhmm->hmm);
-    }
-
-    /* Start search with <s>; word_chan[<s>] is permanently allocated */
-    rhmm = (root_chan_t *) ngs->word_chan[ps_search_start_wid(ngs)];
-    hmm_enter(&rhmm->hmm, 0, NO_BP, 0);
-    ngs->active_word_list[0][0] = ps_search_start_wid(ngs);
-    ngs->n_active_word[0] = 1;
-
-    ngs->best_score = 0;
-    ngs->renormalized = FALSE;
-
-    for (i = 0; i < ps_search_n_words(ngs); i++)
-        ngs->last_ltrans[i].sf = -1;
-
-    if (!ngs->fwdtree)
-        ngs->n_frame = 0;
-
-    ngs->st.n_fwdflat_chan = 0;
-    ngs->st.n_fwdflat_words = 0;
-    ngs->st.n_fwdflat_word_transition = 0;
-    ngs->st.n_senone_active_utt = 0;
-}
-
-static void
-compute_fwdflat_sen_active(ngram_search_t *ngs, int frame_idx)
-{
-    int32 i, nw, w;
-    int32 *awl;
-    root_chan_t *rhmm;
-    chan_t *hmm;
-
-    acmod_clear_active(ps_search_acmod(ngs));
-
-    nw = ngs->n_active_word[frame_idx & 0x1];
-    awl = ngs->active_word_list[frame_idx & 0x1];
-
-    for (i = 0; i < nw; i++) {
-        w = *(awl++);
-        rhmm = (root_chan_t *)ngs->word_chan[w];
-        if (hmm_frame(&rhmm->hmm) == frame_idx) {
-            acmod_activate_hmm(ps_search_acmod(ngs), &rhmm->hmm);
-        }
-
-        for (hmm = rhmm->next; hmm; hmm = hmm->next) {
-            if (hmm_frame(&hmm->hmm) == frame_idx) {
-                acmod_activate_hmm(ps_search_acmod(ngs), &hmm->hmm);
-            }
-        }
-    }
-}
-
-static void
-fwdflat_eval_chan(ngram_search_t *ngs, int frame_idx)
-{
-    int32 i, w, nw, bestscore;
-    int32 *awl;
-    root_chan_t *rhmm;
-    chan_t *hmm;
-
-    nw = ngs->n_active_word[frame_idx & 0x1];
-    awl = ngs->active_word_list[frame_idx & 0x1];
-    bestscore = WORST_SCORE;
-
-    ngs->st.n_fwdflat_words += nw;
-
-    /* Scan all active words. */
-    for (i = 0; i < nw; i++) {
-        w = *(awl++);
-        rhmm = (root_chan_t *) ngs->word_chan[w];
-        if (hmm_frame(&rhmm->hmm) == frame_idx) {
-            int32 score = chan_v_eval(rhmm);
-            if ((score BETTER_THAN bestscore) && (w != ps_search_finish_wid(ngs)))
-                bestscore = score;
-            ngs->st.n_fwdflat_chan++;
-        }
-
-        for (hmm = rhmm->next; hmm; hmm = hmm->next) {
-            if (hmm_frame(&hmm->hmm) == frame_idx) {
-                int32 score = chan_v_eval(hmm);
-                if (score BETTER_THAN bestscore)
-                    bestscore = score;
-                ngs->st.n_fwdflat_chan++;
-            }
-        }
-    }
-
-    ngs->best_score = bestscore;
-}
-
-static void
-fwdflat_prune_chan(ngram_search_t *ngs, int frame_idx)
-{
-    int32 i, nw, cf, nf, w, pip, newscore, thresh, wordthresh;
-    int32 *awl;
-    root_chan_t *rhmm;
-    chan_t *hmm, *nexthmm;
-
-    cf = frame_idx;
-    nf = cf + 1;
-    nw = ngs->n_active_word[cf & 0x1];
-    awl = ngs->active_word_list[cf & 0x1];
-    bitvec_clear_all(ngs->word_active, ps_search_n_words(ngs));
-
-    thresh = ngs->best_score + ngs->fwdflatbeam;
-    wordthresh = ngs->best_score + ngs->fwdflatwbeam;
-    pip = ngs->pip;
-    E_DEBUG(3,("frame %d thresh %d wordthresh %d\n", frame_idx, thresh, wordthresh));
-
-    /* Scan all active words. */
-    for (i = 0; i < nw; i++) {
-        w = *(awl++);
-        rhmm = (root_chan_t *) ngs->word_chan[w];
-        /* Propagate active root channels */
-        if (hmm_frame(&rhmm->hmm) == cf
-            && hmm_bestscore(&rhmm->hmm) BETTER_THAN thresh) {
-            hmm_frame(&rhmm->hmm) = nf;
-            bitvec_set(ngs->word_active, w);
-
-            /* Transitions out of root channel */
-            newscore = hmm_out_score(&rhmm->hmm);
-            if (rhmm->next) {
-                assert(!dict_is_single_phone(ps_search_dict(ngs), w));
-
-                newscore += pip;
-                if (newscore BETTER_THAN thresh) {
-                    hmm = rhmm->next;
-                    /* Enter all right context phones */
-                    if (hmm->info.rc_id >= 0) {
-                        for (; hmm; hmm = hmm->next) {
-                            if ((hmm_frame(&hmm->hmm) < cf)
-                                || (newscore BETTER_THAN hmm_in_score(&hmm->hmm))) {
-                                hmm_enter(&hmm->hmm, newscore,
-                                          hmm_out_history(&rhmm->hmm), nf);
-                            }
-                        }
-                    }
-                    /* Just a normal word internal phone */
-                    else {
-                        if ((hmm_frame(&hmm->hmm) < cf)
-                            || (newscore BETTER_THAN hmm_in_score(&hmm->hmm))) {
-                                hmm_enter(&hmm->hmm, newscore,
-                                          hmm_out_history(&rhmm->hmm), nf);
-                        }
-                    }
-                }
-            }
-            else {
-                assert(dict_is_single_phone(ps_search_dict(ngs), w));
-
-                /* Word exit for single-phone words (where did their
-                 * whmms come from?) (either from
-                 * ngram_search_fwdtree, or from
-                 * ngram_fwdflat_allocate_1ph(), that's where) */
-                if (newscore BETTER_THAN wordthresh) {
-                    ngram_search_save_bp(ngs, cf, w, newscore,
-                                         hmm_out_history(&rhmm->hmm), 0);
-                }
-            }
-        }
-
-        /* Transitions out of non-root channels. */
-        for (hmm = rhmm->next; hmm; hmm = hmm->next) {
-            if (hmm_frame(&hmm->hmm) >= cf) {
-                /* Propagate forward HMMs inside the beam. */
-                if (hmm_bestscore(&hmm->hmm) BETTER_THAN thresh) {
-                    hmm_frame(&hmm->hmm) = nf;
-                    bitvec_set(ngs->word_active, w);
-
-                    newscore = hmm_out_score(&hmm->hmm);
-                    /* Word-internal phones */
-                    if (hmm->info.rc_id < 0) {
-                        newscore += pip;
-                        if (newscore BETTER_THAN thresh) {
-                            nexthmm = hmm->next;
-                            /* Enter all right-context phones. */
-                            if (nexthmm->info.rc_id >= 0) {
-                                 for (; nexthmm; nexthmm = nexthmm->next) {
-                                    if ((hmm_frame(&nexthmm->hmm) < cf)
-                                        || (newscore BETTER_THAN
-                                            hmm_in_score(&nexthmm->hmm))) {
-                                        hmm_enter(&nexthmm->hmm,
-                                                  newscore,
-                                                  hmm_out_history(&hmm->hmm),
-                                                  nf);
-                                    }
-                                }
-                            }
-                            /* Enter single word-internal phone. */
-                            else {
-                                if ((hmm_frame(&nexthmm->hmm) < cf)
-                                    || (newscore BETTER_THAN
-                                        hmm_in_score(&nexthmm->hmm))) {
-                                    hmm_enter(&nexthmm->hmm, newscore,
-                                              hmm_out_history(&hmm->hmm), nf);
-                                }
-                            }
-                        }
-                    }
-                    /* Right-context phones - apply word beam and exit. */
-                    else {
-                        if (newscore BETTER_THAN wordthresh) {
-                            ngram_search_save_bp(ngs, cf, w, newscore,
-                                                 hmm_out_history(&hmm->hmm),
-                                                 hmm->info.rc_id);
-                        }
-                    }
-                }
-                /* Zero out inactive HMMs. */
-                else if (hmm_frame(&hmm->hmm) != nf) {
-                    hmm_clear_scores(&hmm->hmm);
-                }
-            }
-        }
-    }
-}
-
-static void
-get_expand_wordlist(ngram_search_t *ngs, int32 frm, int32 win)
-{
-    int32 f, sf, ef;
-    ps_latnode_t *node;
-
-    if (!ngs->fwdtree) {
-        ngs->st.n_fwdflat_word_transition += ngs->n_expand_words;
-        return;
-    }
-
-    sf = frm - win;
-    if (sf < 0)
-        sf = 0;
-    ef = frm + win;
-    if (ef > ngs->n_frame)
-        ef = ngs->n_frame;
-
-    bitvec_clear_all(ngs->expand_word_flag, ps_search_n_words(ngs));
-    ngs->n_expand_words = 0;
-
-    for (f = sf; f < ef; f++) {
-        for (node = ngs->frm_wordlist[f]; node; node = node->next) {
-            if (!bitvec_is_set(ngs->expand_word_flag, node->wid)) {
-                ngs->expand_word_list[ngs->n_expand_words++] = node->wid;
-                bitvec_set(ngs->expand_word_flag, node->wid);
-            }
-        }
-    }
-    ngs->expand_word_list[ngs->n_expand_words] = -1;
-    ngs->st.n_fwdflat_word_transition += ngs->n_expand_words;
-}
-
-static void
-fwdflat_word_transition(ngram_search_t *ngs, int frame_idx)
-{
-    int32 cf, nf, b, thresh, pip, i, nw, w, newscore;
-    int32 best_silrc_score = 0, best_silrc_bp = 0;      /* FIXME: good defaults? */
-    bptbl_t *bp;
-    int32 *rcss;
-    root_chan_t *rhmm;
-    int32 *awl;
-    float32 lwf;
-    dict_t *dict = ps_search_dict(ngs);
-    dict2pid_t *d2p = ps_search_dict2pid(ngs);
-
-    cf = frame_idx;
-    nf = cf + 1;
-    thresh = ngs->best_score + ngs->fwdflatbeam;
-    pip = ngs->pip;
-    best_silrc_score = WORST_SCORE;
-    lwf = ngs->fwdflat_fwdtree_lw_ratio;
-
-    /* Search for all words starting within a window of this frame.
-     * These are the successors for words exiting now. */
-    get_expand_wordlist(ngs, cf, ngs->max_sf_win);
-
-    /* Scan words exited in current frame */
-    for (b = ngs->bp_table_idx[cf]; b < ngs->bpidx; b++) {
-        xwdssid_t *rssid;
-        int32 silscore;
-
-        bp = ngs->bp_table + b;
-        ngs->word_lat_idx[bp->wid] = NO_BP;
-
-        if (bp->wid == ps_search_finish_wid(ngs))
-            continue;
-
-        /* DICT2PID location */
-        /* Get the mapping from right context phone ID to index in the
-         * right context table and the bscore_stack. */
-        rcss = ngs->bscore_stack + bp->s_idx;
-        if (bp->last2_phone == -1)
-            rssid = NULL;
-        else
-            rssid = dict2pid_rssid(d2p, bp->last_phone, bp->last2_phone);
-
-        /* Transition to all successor words. */
-        for (i = 0; ngs->expand_word_list[i] >= 0; i++) {
-            int32 n_used;
-
-            w = ngs->expand_word_list[i];
-
-            /* Get the exit score we recorded in save_bwd_ptr(), or
-             * something approximating it. */
-            if (rssid)
-                newscore = rcss[rssid->cimap[dict_first_phone(dict, w)]];
-            else
-                newscore = bp->score;
-            if (newscore == WORST_SCORE)
-                continue;
-            /* FIXME: Floating point... */
-            newscore += lwf
-                * (ngram_tg_score(ngs->lmset,
-                                  dict_basewid(dict, w),
-                                  bp->real_wid,
-                                  bp->prev_real_wid,
-                                  &n_used) >> SENSCR_SHIFT);
-            newscore += pip;
-
-            /* Enter the next word */
-            if (newscore BETTER_THAN thresh) {
-                rhmm = (root_chan_t *) ngs->word_chan[w];
-                if ((hmm_frame(&rhmm->hmm) < cf)
-                    || (newscore BETTER_THAN hmm_in_score(&rhmm->hmm))) {
-                    hmm_enter(&rhmm->hmm, newscore, b, nf);
-                    /* DICT2PID: This is where mpx ssids get introduced. */
-                    /* Look up the ssid to use when entering this mpx triphone. */
-                    hmm_mpx_ssid(&rhmm->hmm, 0) =
-                        dict2pid_ldiph_lc(d2p, rhmm->ciphone, rhmm->ci2phone,
-                                          dict_last_phone(dict, bp->wid));
-                    assert(IS_S3SSID(hmm_mpx_ssid(&rhmm->hmm, 0)));
-                    E_DEBUG(6,("ssid %d(%d,%d) = %d\n",
-                               rhmm->ciphone, dict_last_phone(dict, bp->wid), rhmm->ci2phone,
-                               hmm_mpx_ssid(&rhmm->hmm, 0)));
-                    bitvec_set(ngs->word_active, w);
-                }
-            }
-        }
-
-        /* Get the best exit into silence. */
-        if (rssid)
-            silscore = rcss[rssid->cimap[ps_search_acmod(ngs)->mdef->sil]];
-        else
-            silscore = bp->score;
-        if (silscore BETTER_THAN best_silrc_score) {
-            best_silrc_score = silscore;
-            best_silrc_bp = b;
-        }
-    }
-
-    /* Transition to <sil> */
-    newscore = best_silrc_score + ngs->silpen + pip;
-    if ((newscore BETTER_THAN thresh) && (newscore BETTER_THAN WORST_SCORE)) {
-        w = ps_search_silence_wid(ngs);
-        rhmm = (root_chan_t *) ngs->word_chan[w];
-        if ((hmm_frame(&rhmm->hmm) < cf)
-            || (newscore BETTER_THAN hmm_in_score(&rhmm->hmm))) {
-            hmm_enter(&rhmm->hmm, newscore,
-                      best_silrc_bp, nf);
-            bitvec_set(ngs->word_active, w);
-        }
-    }
-    /* Transition to noise words */
-    newscore = best_silrc_score + ngs->fillpen + pip;
-    if ((newscore BETTER_THAN thresh) && (newscore BETTER_THAN WORST_SCORE)) {
-        for (w = ps_search_silence_wid(ngs) + 1; w < ps_search_n_words(ngs); w++) {
-            rhmm = (root_chan_t *) ngs->word_chan[w];
-            /* Noise words that aren't a single phone will have NULL here. */
-            if (rhmm == NULL)
-                continue;
-            if ((hmm_frame(&rhmm->hmm) < cf)
-                || (newscore BETTER_THAN hmm_in_score(&rhmm->hmm))) {
-                hmm_enter(&rhmm->hmm, newscore,
-                          best_silrc_bp, nf);
-                bitvec_set(ngs->word_active, w);
-            }
-        }
-    }
-
-    /* Reset initial channels of words that have become inactive even after word trans. */
-    nw = ngs->n_active_word[cf & 0x1];
-    awl = ngs->active_word_list[cf & 0x1];
-    for (i = 0; i < nw; i++) {
-        w = *(awl++);
-        rhmm = (root_chan_t *) ngs->word_chan[w];
-        if (hmm_frame(&rhmm->hmm) == cf) {
-            hmm_clear_scores(&rhmm->hmm);
-        }
-    }
-}
-
-static void
-fwdflat_renormalize_scores(ngram_search_t *ngs, int frame_idx, int32 norm)
-{
-    root_chan_t *rhmm;
-    chan_t *hmm;
-    int32 i, nw, cf, w, *awl;
-
-    cf = frame_idx;
-
-    /* Renormalize individual word channels */
-    nw = ngs->n_active_word[cf & 0x1];
-    awl = ngs->active_word_list[cf & 0x1];
-    for (i = 0; i < nw; i++) {
-        w = *(awl++);
-        rhmm = (root_chan_t *) ngs->word_chan[w];
-        if (hmm_frame(&rhmm->hmm) == cf) {
-            hmm_normalize(&rhmm->hmm, norm);
-        }
-        for (hmm = rhmm->next; hmm; hmm = hmm->next) {
-            if (hmm_frame(&hmm->hmm) == cf) {
-                hmm_normalize(&hmm->hmm, norm);
-            }
-        }
-    }
-
-    ngs->renormalized = TRUE;
-}
-
-int
-ngram_fwdflat_search(ngram_search_t *ngs, int frame_idx)
-{
-    int16 const *senscr;
-    int32 nf, i, j;
-    int32 *nawl;
-
-    /* Activate our HMMs for the current frame if need be. */
-    if (!ps_search_acmod(ngs)->compallsen)
-        compute_fwdflat_sen_active(ngs, frame_idx);
-
-    /* Compute GMM scores for the current frame. */
-    senscr = acmod_score(ps_search_acmod(ngs), &frame_idx);
-    ngs->st.n_senone_active_utt += ps_search_acmod(ngs)->n_senone_active;
-
-    /* Mark backpointer table for current frame. */
-    ngram_search_mark_bptable(ngs, frame_idx);
-
-    /* If the best score is equal to or worse than WORST_SCORE,
-     * recognition has failed, don't bother to keep trying. */
-    if (ngs->best_score == WORST_SCORE || ngs->best_score WORSE_THAN WORST_SCORE)
-        return 0;
-    /* Renormalize if necessary */
-    if (ngs->best_score + (2 * ngs->beam) WORSE_THAN WORST_SCORE) {
-        E_INFO("Renormalizing Scores at frame %d, best score %d\n",
-               frame_idx, ngs->best_score);
-        fwdflat_renormalize_scores(ngs, frame_idx, ngs->best_score);
-    }
-
-    ngs->best_score = WORST_SCORE;
-    hmm_context_set_senscore(ngs->hmmctx, senscr);
-
-    /* Evaluate HMMs */
-    fwdflat_eval_chan(ngs, frame_idx);
-    /* Prune HMMs and do phone transitions. */
-    fwdflat_prune_chan(ngs, frame_idx);
-    /* Do word transitions. */
-    fwdflat_word_transition(ngs, frame_idx);
-
-    /* Create next active word list, skip fillers */
-    nf = frame_idx + 1;
-    nawl = ngs->active_word_list[nf & 0x1];
-    for (i = 0, j = 0; ngs->fwdflat_wordlist[i] >= 0; i++) {
-        int32 wid = ngs->fwdflat_wordlist[i];
-        if (bitvec_is_set(ngs->word_active, wid) && wid < ps_search_start_wid(ngs)) {
-            *(nawl++) = wid;
-            j++;
-        }
-    }
-    /* Add fillers */
-    for (i = ps_search_start_wid(ngs); i < ps_search_n_words(ngs); i++) {
-        if (bitvec_is_set(ngs->word_active, i)) {
-            *(nawl++) = i;
-            j++;
-        }
-    }
-    if (!ngs->fwdtree)
-        ++ngs->n_frame;
-    ngs->n_active_word[nf & 0x1] = j;
-
-    /* Return the number of frames processed. */
-    return 1;
-}
-
-/**
- * Destroy wordlist from the current utterance.
- */
-static void
-destroy_fwdflat_wordlist(ngram_search_t *ngs)
-{
-    ps_latnode_t *node, *tnode;
-    int32 f;
-
-    if (!ngs->fwdtree)
-        return;
-
-    for (f = 0; f < ngs->n_frame; f++) {
-        for (node = ngs->frm_wordlist[f]; node; node = tnode) {
-            tnode = node->next;
-            listelem_free(ngs->latnode_alloc, node);
-        }
-    }
-}
-
-/**
- * Free HMM network for one utterance of fwdflat search.
- */
-static void
-destroy_fwdflat_chan(ngram_search_t *ngs)
-{
-    int32 i, wid;
-
-    for (i = 0; ngs->fwdflat_wordlist[i] >= 0; i++) {
-        root_chan_t *rhmm;
-        chan_t *thmm;
-        wid = ngs->fwdflat_wordlist[i];
-        if (dict_is_single_phone(ps_search_dict(ngs),wid))
-            continue;
-        assert(ngs->word_chan[wid] != NULL);
-
-        /* The first HMM in ngs->word_chan[wid] was allocated with
-         * ngs->root_chan_alloc, but this will attempt to free it
-         * using ngs->chan_alloc, which will not work.  Therefore we
-         * free it manually and move the list forward before handing
-         * it off. */
-        rhmm = (root_chan_t *)ngs->word_chan[wid];
-        thmm = rhmm->next;
-        listelem_free(ngs->root_chan_alloc, rhmm);
-        ngs->word_chan[wid] = thmm;
-        ngram_search_free_all_rc(ngs, wid);
-    }
-}
-
-void
-ngram_fwdflat_finish(ngram_search_t *ngs)
-{
-    int32 cf;
-
-    destroy_fwdflat_chan(ngs);
-    destroy_fwdflat_wordlist(ngs);
-    bitvec_clear_all(ngs->word_active, ps_search_n_words(ngs));
-
-    /* This is the number of frames processed. */
-    cf = ps_search_acmod(ngs)->output_frame;
-    /* Add a mark in the backpointer table for one past the final frame. */
-    ngram_search_mark_bptable(ngs, cf);
-
-    ptmr_stop(&ngs->fwdflat_perf);
-    /* Print out some statistics. */
-    if (cf > 0) {
-        double n_speech = (double)(cf + 1)
-            / cmd_ln_int32_r(ps_search_config(ngs), "-frate");
-        E_INFO("%8d words recognized (%d/fr)\n",
-               ngs->bpidx, (ngs->bpidx + (cf >> 1)) / (cf + 1));
-        E_INFO("%8d senones evaluated (%d/fr)\n", ngs->st.n_senone_active_utt,
-               (ngs->st.n_senone_active_utt + (cf >> 1)) / (cf + 1));
-        E_INFO("%8d channels searched (%d/fr)\n",
-               ngs->st.n_fwdflat_chan, ngs->st.n_fwdflat_chan / (cf + 1));
-        E_INFO("%8d words searched (%d/fr)\n",
-               ngs->st.n_fwdflat_words, ngs->st.n_fwdflat_words / (cf + 1));
-        E_INFO("%8d word transitions (%d/fr)\n",
-               ngs->st.n_fwdflat_word_transition,
-               ngs->st.n_fwdflat_word_transition / (cf + 1));
-        E_INFO("fwdflat %.2f CPU %.3f xRT\n",
-               ngs->fwdflat_perf.t_cpu,
-               ngs->fwdflat_perf.t_cpu / n_speech);
-        E_INFO("fwdflat %.2f wall %.3f xRT\n",
-               ngs->fwdflat_perf.t_elapsed,
-               ngs->fwdflat_perf.t_elapsed / n_speech);
-    }
-}