Add m-esr52 at 52.6.0

1 files changed, 1573 insertions, 0 deletions

diff --git a/media/pocketsphinx/src/ngram_search_fwdtree.c b/media/pocketsphinx/src/ngram_search_fwdtree.c
new file mode 100644
index 000000000..6665161f8
--- /dev/null
+++ b/media/pocketsphinx/src/ngram_search_fwdtree.c
@@ -0,0 +1,1573 @@
+/* -*- 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_fwdtree.c Lexicon tree 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_fwdtree.h"
+#include "phone_loop_search.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
+
+/*
+ * Allocate that part of the search channel tree structure that is independent of the
+ * LM in use.
+ */
+static void
+init_search_tree(ngram_search_t *ngs)
+{
+    int32 w, ndiph, i, n_words, n_ci;
+    dict_t *dict = ps_search_dict(ngs);
+    bitvec_t *dimap;
+
+    n_words = ps_search_n_words(ngs);
+    ngs->homophone_set = ckd_calloc(n_words, sizeof(*ngs->homophone_set));
+
+    /* Find #single phone words, and #unique first diphones (#root channels) in dict. */
+    ndiph = 0;
+    ngs->n_1ph_words = 0;
+    n_ci = bin_mdef_n_ciphone(ps_search_acmod(ngs)->mdef);
+    /* Allocate a bitvector with flags for each possible diphone. */
+    dimap = bitvec_alloc(n_ci * n_ci);
+    for (w = 0; w < n_words; w++) {
+        if (!dict_real_word(dict, w))
+            continue;
+        if (dict_is_single_phone(dict, w))
+            ++ngs->n_1ph_words;
+        else {
+            int ph0, ph1;
+            ph0 = dict_first_phone(dict, w);
+            ph1 = dict_second_phone(dict, w);
+            /* Increment ndiph the first time we see a diphone. */
+            if (bitvec_is_clear(dimap, ph0 * n_ci + ph1)) {
+                bitvec_set(dimap, ph0 * n_ci + ph1);
+                ++ndiph;
+            }
+        }
+    }
+    E_INFO("%d unique initial diphones\n", ndiph);
+    bitvec_free(dimap);
+
+    /* Add remaining dict words (</s>, <s>, <sil>, noise words) to single-phone words */
+    ngs->n_1ph_words += dict_num_fillers(dict) + 2;
+    ngs->n_root_chan_alloc = ndiph + 1;
+    /* Verify that these are all *actually* single-phone words,
+     * otherwise really bad things will happen to us. */
+    for (w = 0; w < n_words; ++w) {
+        if (dict_real_word(dict, w))
+            continue;
+        if (!dict_is_single_phone(dict, w)) {
+            E_WARN("Filler word %d = %s has more than one phone, ignoring it.\n",
+                   w, dict_wordstr(dict, w));
+            --ngs->n_1ph_words;
+        }
+    }
+
+    /* Allocate and initialize root channels */
+    ngs->root_chan =
+        ckd_calloc(ngs->n_root_chan_alloc, sizeof(*ngs->root_chan));
+    for (i = 0; i < ngs->n_root_chan_alloc; i++) {
+        hmm_init(ngs->hmmctx, &ngs->root_chan[i].hmm, TRUE, -1, -1);
+        ngs->root_chan[i].penult_phn_wid = -1;
+        ngs->root_chan[i].next = NULL;
+    }
+
+    /* Permanently allocate and initialize channels for single-phone
+     * words (1/word). */
+    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;
+        /* Use SIL as right context for these. */
+        ngs->rhmm_1ph[i].ci2phone = bin_mdef_silphone(ps_search_acmod(ngs)->mdef);
+        ngs->rhmm_1ph[i].ciphone = dict_first_phone(dict, w);
+        hmm_init(ngs->hmmctx, &ngs->rhmm_1ph[i].hmm, TRUE,
+                 bin_mdef_pid2ssid(ps_search_acmod(ngs)->mdef, ngs->rhmm_1ph[i].ciphone),
+                 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]);
+        i++;
+    }
+
+    ngs->single_phone_wid = ckd_calloc(ngs->n_1ph_words,
+                                       sizeof(*ngs->single_phone_wid));
+    E_INFO("%d root, %d non-root channels, %d single-phone words\n",
+           ngs->n_root_chan, ngs->n_nonroot_chan, ngs->n_1ph_words);
+}
+
+/*
+ * One-time initialization of internal channels in HMM tree.
+ */
+static void
+init_nonroot_chan(ngram_search_t *ngs, chan_t * hmm, int32 ph, int32 ci, int32 tmatid)
+{
+    hmm->next = NULL;
+    hmm->alt = NULL;
+    hmm->info.penult_phn_wid = -1;
+    hmm->ciphone = ci;
+    hmm_init(ngs->hmmctx, &hmm->hmm, FALSE, ph, tmatid);
+}
+
+/*
+ * Allocate and initialize search channel-tree structure.
+ * At this point, all the root-channels have been allocated and partly initialized
+ * (as per init_search_tree()), and channels for all the single-phone words have been
+ * allocated and initialized.  None of the interior channels of search-trees have
+ * been allocated.
+ * This routine may be called on every utterance, after reinit_search_tree() clears
+ * the search tree created for the previous utterance.  Meant for reconfiguring the
+ * search tree to suit the currently active LM.
+ */
+static void
+create_search_tree(ngram_search_t *ngs)
+{
+    chan_t *hmm;
+    root_chan_t *rhmm;
+    int32 w, i, j, p, ph, tmatid;
+    int32 n_words;
+    dict_t *dict = ps_search_dict(ngs);
+    dict2pid_t *d2p = ps_search_dict2pid(ngs);
+
+    n_words = ps_search_n_words(ngs);
+
+    E_INFO("Creating search tree\n");
+
+    for (w = 0; w < n_words; w++)
+        ngs->homophone_set[w] = -1;
+
+    E_INFO("before: %d root, %d non-root channels, %d single-phone words\n",
+           ngs->n_root_chan, ngs->n_nonroot_chan, ngs->n_1ph_words);
+
+    ngs->n_1ph_LMwords = 0;
+    ngs->n_root_chan = 0;
+    ngs->n_nonroot_chan = 0;
+
+    for (w = 0; w < n_words; w++) {
+        int ciphone, ci2phone;
+
+        /* Ignore dictionary words not in LM */
+        if (!ngram_model_set_known_wid(ngs->lmset, dict_basewid(dict, w)))
+            continue;
+
+        /* Handle single-phone words individually; not in channel tree */
+        if (dict_is_single_phone(dict, w)) {
+            E_DEBUG(1,("single_phone_wid[%d] = %s\n",
+                       ngs->n_1ph_LMwords, dict_wordstr(dict, w)));
+            ngs->single_phone_wid[ngs->n_1ph_LMwords++] = w;
+            continue;
+        }
+
+        /* Find a root channel matching the initial diphone, or
+         * allocate one if not found. */
+        ciphone = dict_first_phone(dict, w);
+        ci2phone = dict_second_phone(dict, w);
+        for (i = 0; i < ngs->n_root_chan; ++i) {
+            if (ngs->root_chan[i].ciphone == ciphone
+                && ngs->root_chan[i].ci2phone == ci2phone)
+                break;
+        }
+        if (i == ngs->n_root_chan) {
+            rhmm = &(ngs->root_chan[ngs->n_root_chan]);
+            rhmm->hmm.tmatid = bin_mdef_pid2tmatid(ps_search_acmod(ngs)->mdef, ciphone);
+            /* Begin with CI phone?  Not sure this makes a difference... */
+            hmm_mpx_ssid(&rhmm->hmm, 0) =
+                bin_mdef_pid2ssid(ps_search_acmod(ngs)->mdef, ciphone);
+            rhmm->ciphone = ciphone;
+            rhmm->ci2phone = ci2phone;
+            ngs->n_root_chan++;
+        }
+        else
+            rhmm = &(ngs->root_chan[i]);
+
+        E_DEBUG(3,("word %s rhmm %d\n", dict_wordstr(dict, w), rhmm - ngs->root_chan));
+        /* Now, rhmm = root channel for w.  Go on to remaining phones */
+        if (dict_pronlen(dict, w) == 2) {
+            /* Next phone is the last; not kept in tree; add w to penult_phn_wid set */
+            if ((j = rhmm->penult_phn_wid) < 0)
+                rhmm->penult_phn_wid = w;
+            else {
+                for (; ngs->homophone_set[j] >= 0; j = ngs->homophone_set[j]);
+                ngs->homophone_set[j] = w;
+            }
+        }
+        else {
+            /* Add remaining phones, except the last, to tree */
+            ph = dict2pid_internal(d2p, w, 1);
+            tmatid = bin_mdef_pid2tmatid(ps_search_acmod(ngs)->mdef, dict_pron(dict, w, 1));
+            hmm = rhmm->next;
+            if (hmm == NULL) {
+                rhmm->next = hmm = listelem_malloc(ngs->chan_alloc);
+                init_nonroot_chan(ngs, hmm, ph, dict_pron(dict, w, 1), tmatid);
+                ngs->n_nonroot_chan++;
+            }
+            else {
+                chan_t *prev_hmm = NULL;
+
+                for (; hmm && (hmm_nonmpx_ssid(&hmm->hmm) != ph); hmm = hmm->alt)
+                    prev_hmm = hmm;
+                if (!hmm) {     /* thanks, rkm! */
+                    prev_hmm->alt = hmm = listelem_malloc(ngs->chan_alloc);
+                    init_nonroot_chan(ngs, hmm, ph, dict_pron(dict, w, 1), tmatid);
+                    ngs->n_nonroot_chan++;
+                }
+            }
+            E_DEBUG(3,("phone %s = %d\n",
+                       bin_mdef_ciphone_str(ps_search_acmod(ngs)->mdef,
+                                            dict_second_phone(dict, w)), ph));
+            for (p = 2; p < dict_pronlen(dict, w) - 1; p++) {
+                ph = dict2pid_internal(d2p, w, p);
+                tmatid = bin_mdef_pid2tmatid(ps_search_acmod(ngs)->mdef, dict_pron(dict, w, p));
+                if (!hmm->next) {
+                    hmm->next = listelem_malloc(ngs->chan_alloc);
+                    hmm = hmm->next;
+                    init_nonroot_chan(ngs, hmm, ph, dict_pron(dict, w, p), tmatid);
+                    ngs->n_nonroot_chan++;
+                }
+                else {
+                    chan_t *prev_hmm = NULL;
+
+                    for (hmm = hmm->next; hmm && (hmm_nonmpx_ssid(&hmm->hmm) != ph);
+                         hmm = hmm->alt)
+                        prev_hmm = hmm;
+                    if (!hmm) { /* thanks, rkm! */
+                        prev_hmm->alt = hmm = listelem_malloc(ngs->chan_alloc);
+                        init_nonroot_chan(ngs, hmm, ph, dict_pron(dict, w, p), tmatid);
+                        ngs->n_nonroot_chan++;
+                    }
+                }
+                E_DEBUG(3,("phone %s = %d\n",
+                           bin_mdef_ciphone_str(ps_search_acmod(ngs)->mdef,
+                                                dict_pron(dict, w, p)), ph));
+            }
+
+            /* All but last phone of w in tree; add w to hmm->info.penult_phn_wid set */
+            if ((j = hmm->info.penult_phn_wid) < 0)
+                hmm->info.penult_phn_wid = w;
+            else {
+                for (; ngs->homophone_set[j] >= 0; j = ngs->homophone_set[j]);
+                ngs->homophone_set[j] = w;
+            }
+        }
+    }
+
+    ngs->n_1ph_words = ngs->n_1ph_LMwords;
+
+    /* Add filler words to the array of 1ph words. */
+    for (w = 0; w < n_words; ++w) {
+        /* Skip anything that doesn't actually have a single phone. */
+        if (!dict_is_single_phone(dict, w))
+            continue;
+        /* Also skip "real words" and things that are in the LM. */
+        if (dict_real_word(dict, w))
+            continue;
+        if (ngram_model_set_known_wid(ngs->lmset, dict_basewid(dict, w)))
+            continue;
+        E_DEBUG(1,("single_phone_wid[%d] = %s\n",
+                   ngs->n_1ph_words, dict_wordstr(dict, w)));
+        ngs->single_phone_wid[ngs->n_1ph_words++] = w;
+    }
+
+    if (ngs->n_nonroot_chan >= ngs->max_nonroot_chan) {
+        /* Give some room for channels for new words added dynamically at run time */
+        ngs->max_nonroot_chan = ngs->n_nonroot_chan + 128;
+        E_INFO("after: max nonroot chan increased to %d\n", ngs->max_nonroot_chan);
+
+        /* Free old active channel list array if any and allocate new one */
+        if (ngs->active_chan_list)
+            ckd_free_2d(ngs->active_chan_list);
+        ngs->active_chan_list = ckd_calloc_2d(2, ngs->max_nonroot_chan,
+                                              sizeof(**ngs->active_chan_list));
+    }
+
+    if (!ngs->n_root_chan)
+	E_ERROR("No word from the language model has pronunciation in the dictionary\n");
+
+    E_INFO("after: %d root, %d non-root channels, %d single-phone words\n",
+           ngs->n_root_chan, ngs->n_nonroot_chan, ngs->n_1ph_words);
+}
+
+static void
+reinit_search_subtree(ngram_search_t *ngs, chan_t * hmm)
+{
+    chan_t *child, *sibling;
+
+    /* First free all children under hmm */
+    for (child = hmm->next; child; child = sibling) {
+        sibling = child->alt;
+        reinit_search_subtree(ngs, child);
+    }
+
+    /* Now free hmm */
+    hmm_deinit(&hmm->hmm);
+    listelem_free(ngs->chan_alloc, hmm);
+}
+
+/*
+ * Delete search tree by freeing all interior channels within search tree and
+ * restoring root channel state to the init state (i.e., just after init_search_tree()).
+ */
+static void
+reinit_search_tree(ngram_search_t *ngs)
+{
+    int32 i;
+    chan_t *hmm, *sibling;
+
+    for (i = 0; i < ngs->n_root_chan; i++) {
+        hmm = ngs->root_chan[i].next;
+
+        while (hmm) {
+            sibling = hmm->alt;
+            reinit_search_subtree(ngs, hmm);
+            hmm = sibling;
+        }
+
+        ngs->root_chan[i].penult_phn_wid = -1;
+        ngs->root_chan[i].next = NULL;
+    }
+    ngs->n_nonroot_chan = 0;
+}
+
+void
+ngram_fwdtree_init(ngram_search_t *ngs)
+{
+    /* Allocate bestbp_rc, lastphn_cand, last_ltrans */
+    ngs->bestbp_rc = ckd_calloc(bin_mdef_n_ciphone(ps_search_acmod(ngs)->mdef),
+                                sizeof(*ngs->bestbp_rc));
+    ngs->lastphn_cand = ckd_calloc(ps_search_n_words(ngs),
+                                   sizeof(*ngs->lastphn_cand));
+    init_search_tree(ngs);
+    create_search_tree(ngs);
+}
+
+static void
+deinit_search_tree(ngram_search_t *ngs)
+{
+    int i, w, n_words;
+
+    n_words = ps_search_n_words(ngs);
+    for (i = 0; i < ngs->n_root_chan_alloc; i++) {
+        hmm_deinit(&ngs->root_chan[i].hmm);
+    }
+    if (ngs->rhmm_1ph) {
+        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;
+    }
+    ngs->n_root_chan = 0;
+    ngs->n_root_chan_alloc = 0;
+    ckd_free(ngs->root_chan);
+    ngs->root_chan = NULL;
+    ckd_free(ngs->single_phone_wid);
+    ngs->single_phone_wid = NULL;
+    ckd_free(ngs->homophone_set);
+    ngs->homophone_set = NULL;
+}
+
+void
+ngram_fwdtree_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 fwdtree %.2f CPU %.3f xRT\n",
+           ngs->fwdtree_perf.t_tot_cpu,
+           ngs->fwdtree_perf.t_tot_cpu / n_speech);
+    E_INFO("TOTAL fwdtree %.2f wall %.3f xRT\n",
+           ngs->fwdtree_perf.t_tot_elapsed,
+           ngs->fwdtree_perf.t_tot_elapsed / n_speech);
+
+    /* Reset non-root channels. */
+    reinit_search_tree(ngs);
+    /* Free the search tree. */
+    deinit_search_tree(ngs);
+    /* Free other stuff. */
+    ngs->max_nonroot_chan = 0;
+    ckd_free_2d(ngs->active_chan_list);
+    ngs->active_chan_list = NULL;
+    ckd_free(ngs->cand_sf);
+    ngs->cand_sf = NULL;
+    ckd_free(ngs->bestbp_rc);
+    ngs->bestbp_rc = NULL;
+    ckd_free(ngs->lastphn_cand);
+    ngs->lastphn_cand = NULL;
+}
+
+int
+ngram_fwdtree_reinit(ngram_search_t *ngs)
+{
+    /* Reset non-root channels. */
+    reinit_search_tree(ngs);
+    /* Free the search tree. */
+    deinit_search_tree(ngs);
+    /* Reallocate things that depend on the number of words. */
+    ckd_free(ngs->lastphn_cand);
+    ngs->lastphn_cand = ckd_calloc(ps_search_n_words(ngs),
+                                   sizeof(*ngs->lastphn_cand));
+    ckd_free(ngs->word_chan);
+    ngs->word_chan = ckd_calloc(ps_search_n_words(ngs),
+                                sizeof(*ngs->word_chan));
+    /* Rebuild the search tree. */
+    init_search_tree(ngs);
+    create_search_tree(ngs);
+    return 0;
+}
+
+void
+ngram_fwdtree_start(ngram_search_t *ngs)
+{
+    ps_search_t *base = (ps_search_t *)ngs;
+    int32 i, w, n_words;
+    root_chan_t *rhmm;
+
+    n_words = ps_search_n_words(ngs);
+
+    /* Reset utterance statistics. */
+    memset(&ngs->st, 0, sizeof(ngs->st));
+    ptmr_reset(&ngs->fwdtree_perf);
+    ptmr_start(&ngs->fwdtree_perf);
+
+    /* Reset backpointer table. */
+    ngs->bpidx = 0;
+    ngs->bss_head = 0;
+
+    /* Reset word lattice. */
+    for (i = 0; i < n_words; ++i)
+        ngs->word_lat_idx[i] = NO_BP;
+
+    /* Reset active HMM and word lists. */
+    ngs->n_active_chan[0] = ngs->n_active_chan[1] = 0;
+    ngs->n_active_word[0] = ngs->n_active_word[1] = 0;
+
+    /* Reset scores. */
+    ngs->best_score = 0;
+    ngs->renormalized = 0;
+
+    /* Reset other stuff. */
+    for (i = 0; i < n_words; i++)
+        ngs->last_ltrans[i].sf = -1;
+    ngs->n_frame = 0;
+
+    /* Clear the hypothesis string. */
+    ckd_free(base->hyp_str);
+    base->hyp_str = NULL;
+
+    /* Reset the permanently allocated single-phone words, since they
+     * may have junk left over in them from FWDFLAT. */
+    for (i = 0; i < ngs->n_1ph_words; i++) {
+        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[dict_startwid(ps_search_dict(ngs))];
+    hmm_clear(&rhmm->hmm);
+    hmm_enter(&rhmm->hmm, 0, NO_BP, 0);
+}
+
+/*
+ * Mark the active senones for all senones belonging to channels that are active in the
+ * current frame.
+ */
+static void
+compute_sen_active(ngram_search_t *ngs, int frame_idx)
+{
+    root_chan_t *rhmm;
+    chan_t *hmm, **acl;
+    int32 i, w, *awl;
+
+    acmod_clear_active(ps_search_acmod(ngs));
+
+    /* Flag active senones for root channels */
+    for (i = ngs->n_root_chan, rhmm = ngs->root_chan; i > 0; --i, rhmm++) {
+        if (hmm_frame(&rhmm->hmm) == frame_idx)
+            acmod_activate_hmm(ps_search_acmod(ngs), &rhmm->hmm);
+    }
+
+    /* Flag active senones for nonroot channels in HMM tree */
+    i = ngs->n_active_chan[frame_idx & 0x1];
+    acl = ngs->active_chan_list[frame_idx & 0x1];
+    for (hmm = *(acl++); i > 0; --i, hmm = *(acl++)) {
+        acmod_activate_hmm(ps_search_acmod(ngs), &hmm->hmm);
+    }
+
+    /* Flag active senones for individual word channels */
+    i = ngs->n_active_word[frame_idx & 0x1];
+    awl = ngs->active_word_list[frame_idx & 0x1];
+    for (w = *(awl++); i > 0; --i, w = *(awl++)) {
+        for (hmm = ngs->word_chan[w]; hmm; hmm = hmm->next) {
+            acmod_activate_hmm(ps_search_acmod(ngs), &hmm->hmm);
+        }
+    }
+    for (i = 0; i < ngs->n_1ph_words; i++) {
+        w = ngs->single_phone_wid[i];
+        rhmm = (root_chan_t *) ngs->word_chan[w];
+
+        if (hmm_frame(&rhmm->hmm) == frame_idx)
+            acmod_activate_hmm(ps_search_acmod(ngs), &rhmm->hmm);
+    }
+}
+
+static void
+renormalize_scores(ngram_search_t *ngs, int frame_idx, int32 norm)
+{
+    root_chan_t *rhmm;
+    chan_t *hmm, **acl;
+    int32 i, w, *awl;
+
+    /* Renormalize root channels */
+    for (i = ngs->n_root_chan, rhmm = ngs->root_chan; i > 0; --i, rhmm++) {
+        if (hmm_frame(&rhmm->hmm) == frame_idx) {
+            hmm_normalize(&rhmm->hmm, norm);
+        }
+    }
+
+    /* Renormalize nonroot channels in HMM tree */
+    i = ngs->n_active_chan[frame_idx & 0x1];
+    acl = ngs->active_chan_list[frame_idx & 0x1];
+    for (hmm = *(acl++); i > 0; --i, hmm = *(acl++)) {
+        hmm_normalize(&hmm->hmm, norm);
+    }
+
+    /* Renormalize individual word channels */
+    i = ngs->n_active_word[frame_idx & 0x1];
+    awl = ngs->active_word_list[frame_idx & 0x1];
+    for (w = *(awl++); i > 0; --i, w = *(awl++)) {
+        for (hmm = ngs->word_chan[w]; hmm; hmm = hmm->next) {
+            hmm_normalize(&hmm->hmm, norm);
+        }
+    }
+    for (i = 0; i < ngs->n_1ph_words; i++) {
+        w = ngs->single_phone_wid[i];
+        rhmm = (root_chan_t *) ngs->word_chan[w];
+        if (hmm_frame(&rhmm->hmm) == frame_idx) {
+            hmm_normalize(&rhmm->hmm, norm);
+        }
+    }
+
+    ngs->renormalized = TRUE;
+}
+
+static int32
+eval_root_chan(ngram_search_t *ngs, int frame_idx)
+{
+    root_chan_t *rhmm;
+    int32 i, bestscore;
+
+    bestscore = WORST_SCORE;
+    for (i = ngs->n_root_chan, rhmm = ngs->root_chan; i > 0; --i, rhmm++) {
+        if (hmm_frame(&rhmm->hmm) == frame_idx) {
+            int32 score = chan_v_eval(rhmm);
+            if (score BETTER_THAN bestscore)
+                bestscore = score;
+            ++ngs->st.n_root_chan_eval;
+        }
+    }
+    return (bestscore);
+}
+
+static int32
+eval_nonroot_chan(ngram_search_t *ngs, int frame_idx)
+{
+    chan_t *hmm, **acl;
+    int32 i, bestscore;
+
+    i = ngs->n_active_chan[frame_idx & 0x1];
+    acl = ngs->active_chan_list[frame_idx & 0x1];
+    bestscore = WORST_SCORE;
+    ngs->st.n_nonroot_chan_eval += i;
+
+    for (hmm = *(acl++); i > 0; --i, hmm = *(acl++)) {
+        int32 score = chan_v_eval(hmm);
+        assert(hmm_frame(&hmm->hmm) == frame_idx);
+        if (score BETTER_THAN bestscore)
+            bestscore = score;
+    }
+
+    return bestscore;
+}
+
+static int32
+eval_word_chan(ngram_search_t *ngs, int frame_idx)
+{
+    root_chan_t *rhmm;
+    chan_t *hmm;
+    int32 i, w, bestscore, *awl, j, k;
+
+    k = 0;
+    bestscore = WORST_SCORE;
+    awl = ngs->active_word_list[frame_idx & 0x1];
+
+    i = ngs->n_active_word[frame_idx & 0x1];
+    for (w = *(awl++); i > 0; --i, w = *(awl++)) {
+        assert(bitvec_is_set(ngs->word_active, w));
+        bitvec_clear(ngs->word_active, w);
+        assert(ngs->word_chan[w] != NULL);
+
+        for (hmm = ngs->word_chan[w]; hmm; hmm = hmm->next) {
+            int32 score;
+
+            assert(hmm_frame(&hmm->hmm) == frame_idx);
+            score = chan_v_eval(hmm);
+            /*printf("eval word chan %d score %d\n", w, score); */
+
+            if (score BETTER_THAN bestscore)
+                bestscore = score;
+
+            k++;
+        }
+    }
+
+    /* Similarly for statically allocated single-phone words */
+    j = 0;
+    for (i = 0; i < ngs->n_1ph_words; i++) {
+        int32 score;
+
+        w = ngs->single_phone_wid[i];
+        rhmm = (root_chan_t *) ngs->word_chan[w];
+        if (hmm_frame(&rhmm->hmm) < frame_idx)
+            continue;
+
+        score = chan_v_eval(rhmm);
+        /* printf("eval 1ph word chan %d score %d\n", w, score); */
+        if (score BETTER_THAN bestscore && w != ps_search_finish_wid(ngs))
+            bestscore = score;
+
+        j++;
+    }
+
+    ngs->st.n_last_chan_eval += k + j;
+    ngs->st.n_nonroot_chan_eval += k + j;
+    ngs->st.n_word_lastchan_eval +=
+        ngs->n_active_word[frame_idx & 0x1] + j;
+
+    return bestscore;
+}
+
+static int32
+evaluate_channels(ngram_search_t *ngs, int16 const *senone_scores, int frame_idx)
+{
+    int32 bs;
+
+    hmm_context_set_senscore(ngs->hmmctx, senone_scores);
+    ngs->best_score = eval_root_chan(ngs, frame_idx);
+    if ((bs = eval_nonroot_chan(ngs, frame_idx)) BETTER_THAN ngs->best_score)
+        ngs->best_score = bs;
+    if ((bs = eval_word_chan(ngs, frame_idx)) BETTER_THAN ngs->best_score)
+        ngs->best_score = bs;
+    ngs->last_phone_best_score = bs;
+
+    return ngs->best_score;
+}
+
+/*
+ * Prune currently active root channels for next frame.  Also, perform exit
+ * transitions out of them and activate successors.
+ * score[] of pruned root chan set to WORST_SCORE elsewhere.
+ */
+static void
+prune_root_chan(ngram_search_t *ngs, int frame_idx)
+{
+    root_chan_t *rhmm;
+    chan_t *hmm;
+    int32 i, nf, w;
+    int32 thresh, newphone_thresh, lastphn_thresh, newphone_score;
+    chan_t **nacl;              /* next active list */
+    lastphn_cand_t *candp;
+    phone_loop_search_t *pls;
+
+    nf = frame_idx + 1;
+    thresh = ngs->best_score + ngs->dynamic_beam;
+    newphone_thresh = ngs->best_score + ngs->pbeam;
+    lastphn_thresh = ngs->best_score + ngs->lpbeam;
+    nacl = ngs->active_chan_list[nf & 0x1];
+    pls = (phone_loop_search_t *)ps_search_lookahead(ngs);
+
+    for (i = 0, rhmm = ngs->root_chan; i < ngs->n_root_chan; i++, rhmm++) {
+        E_DEBUG(3,("Root channel %d frame %d score %d thresh %d\n",
+                   i, hmm_frame(&rhmm->hmm), hmm_bestscore(&rhmm->hmm), thresh));
+        /* First check if this channel was active in current frame */
+        if (hmm_frame(&rhmm->hmm) < frame_idx)
+            continue;
+
+        if (hmm_bestscore(&rhmm->hmm) BETTER_THAN thresh) {
+            hmm_frame(&rhmm->hmm) = nf;  /* rhmm will be active in next frame */
+            E_DEBUG(3,("Preserving root channel %d score %d\n", i, hmm_bestscore(&rhmm->hmm)));
+            /* transitions out of this root channel */
+            /* transition to all next-level channels in the HMM tree */
+            newphone_score = hmm_out_score(&rhmm->hmm) + ngs->pip;
+            if (pls != NULL || newphone_score BETTER_THAN newphone_thresh) {
+                for (hmm = rhmm->next; hmm; hmm = hmm->alt) {
+                    int32 pl_newphone_score = newphone_score
+                        + phone_loop_search_score(pls, hmm->ciphone);
+                    if (pl_newphone_score BETTER_THAN newphone_thresh) {
+                        if ((hmm_frame(&hmm->hmm) < frame_idx)
+                            || (newphone_score BETTER_THAN hmm_in_score(&hmm->hmm))) {
+                            hmm_enter(&hmm->hmm, newphone_score,
+                                      hmm_out_history(&rhmm->hmm), nf);
+                            *(nacl++) = hmm;
+                        }
+                    }
+                }
+            }
+
+            /*
+             * Transition to last phone of all words for which this is the
+             * penultimate phone (the last phones may need multiple right contexts).
+             * Remember to remove the temporary newword_penalty.
+             */
+            if (pls != NULL || newphone_score BETTER_THAN lastphn_thresh) {
+                for (w = rhmm->penult_phn_wid; w >= 0;
+                     w = ngs->homophone_set[w]) {
+                    int32 pl_newphone_score = newphone_score
+                        + phone_loop_search_score
+                        (pls, dict_last_phone(ps_search_dict(ngs),w));
+                    E_DEBUG(3,("word %s newphone_score %d\n", dict_wordstr(ps_search_dict(ngs), w), newphone_score));
+                    if (pl_newphone_score BETTER_THAN lastphn_thresh) {
+                        candp = ngs->lastphn_cand + ngs->n_lastphn_cand;
+                        ngs->n_lastphn_cand++;
+                        candp->wid = w;
+                        candp->score =
+                            newphone_score - ngs->nwpen;
+                        candp->bp = hmm_out_history(&rhmm->hmm);
+                    }
+                }
+            }
+        }
+    }
+    ngs->n_active_chan[nf & 0x1] = (int)(nacl - ngs->active_chan_list[nf & 0x1]);
+}
+
+/*
+ * Prune currently active nonroot channels in HMM tree for next frame.  Also, perform
+ * exit transitions out of such channels and activate successors.
+ */
+static void
+prune_nonroot_chan(ngram_search_t *ngs, int frame_idx)
+{
+    chan_t *hmm, *nexthmm;
+    int32 nf, w, i;
+    int32 thresh, newphone_thresh, lastphn_thresh, newphone_score;
+    chan_t **acl, **nacl;       /* active list, next active list */
+    lastphn_cand_t *candp;
+    phone_loop_search_t *pls;
+
+    nf = frame_idx + 1;
+
+    thresh = ngs->best_score + ngs->dynamic_beam;
+    newphone_thresh = ngs->best_score + ngs->pbeam;
+    lastphn_thresh = ngs->best_score + ngs->lpbeam;
+    pls = (phone_loop_search_t *)ps_search_lookahead(ngs);
+
+    acl = ngs->active_chan_list[frame_idx & 0x1];   /* currently active HMMs in tree */
+    nacl = ngs->active_chan_list[nf & 0x1] + ngs->n_active_chan[nf & 0x1];
+
+    for (i = ngs->n_active_chan[frame_idx & 0x1], hmm = *(acl++); i > 0;
+         --i, hmm = *(acl++)) {
+        assert(hmm_frame(&hmm->hmm) >= frame_idx);
+
+        if (hmm_bestscore(&hmm->hmm) BETTER_THAN thresh) {
+            /* retain this channel in next frame */
+            if (hmm_frame(&hmm->hmm) != nf) {
+                hmm_frame(&hmm->hmm) = nf;
+                *(nacl++) = hmm;
+            }
+
+            /* transition to all next-level channel in the HMM tree */
+            newphone_score = hmm_out_score(&hmm->hmm) + ngs->pip;
+            if (pls != NULL || newphone_score BETTER_THAN newphone_thresh) {
+                for (nexthmm = hmm->next; nexthmm; nexthmm = nexthmm->alt) {
+                    int32 pl_newphone_score = newphone_score
+                        + phone_loop_search_score(pls, nexthmm->ciphone);
+                    if ((pl_newphone_score BETTER_THAN newphone_thresh)
+                        && ((hmm_frame(&nexthmm->hmm) < frame_idx)
+                            || (newphone_score
+                                BETTER_THAN hmm_in_score(&nexthmm->hmm)))) {
+                        if (hmm_frame(&nexthmm->hmm) != nf) {
+                            /* Keep this HMM on the active list */
+                            *(nacl++) = nexthmm;
+                        }
+                        hmm_enter(&nexthmm->hmm, newphone_score,
+                                  hmm_out_history(&hmm->hmm), nf);
+                    }
+                }
+            }
+
+            /*
+             * Transition to last phone of all words for which this is the
+             * penultimate phone (the last phones may need multiple right contexts).
+             * Remember to remove the temporary newword_penalty.
+             */
+            if (pls != NULL || newphone_score BETTER_THAN lastphn_thresh) {
+                for (w = hmm->info.penult_phn_wid; w >= 0;
+                     w = ngs->homophone_set[w]) {
+                    int32 pl_newphone_score = newphone_score
+                        + phone_loop_search_score
+                        (pls, dict_last_phone(ps_search_dict(ngs),w));
+                    if (pl_newphone_score BETTER_THAN lastphn_thresh) {
+                        candp = ngs->lastphn_cand + ngs->n_lastphn_cand;
+                        ngs->n_lastphn_cand++;
+                        candp->wid = w;
+                        candp->score =
+                            newphone_score - ngs->nwpen;
+                        candp->bp = hmm_out_history(&hmm->hmm);
+                    }
+                }
+            }
+        }
+        else if (hmm_frame(&hmm->hmm) != nf) {
+            hmm_clear(&hmm->hmm);
+        }
+    }
+    ngs->n_active_chan[nf & 0x1] = (int)(nacl - ngs->active_chan_list[nf & 0x1]);
+}
+
+/*
+ * Execute the transition into the last phone for all candidates words emerging from
+ * the HMM tree.  Attach LM scores to such transitions.
+ * (Executed after pruning root and non-root, but before pruning word-chan.)
+ */
+static void
+last_phone_transition(ngram_search_t *ngs, int frame_idx)
+{
+    int32 i, j, k, nf, bp, bpend, w;
+    lastphn_cand_t *candp;
+    int32 *nawl;
+    int32 thresh;
+    int32 bestscore, dscr;
+    chan_t *hmm;
+    bptbl_t *bpe;
+    int32 n_cand_sf = 0;
+
+    nf = frame_idx + 1;
+    nawl = ngs->active_word_list[nf & 0x1];
+    ngs->st.n_lastphn_cand_utt += ngs->n_lastphn_cand;
+
+    /* For each candidate word (entering its last phone) */
+    /* If best LM score and bp for candidate known use it, else sort cands by startfrm */
+    for (i = 0, candp = ngs->lastphn_cand; i < ngs->n_lastphn_cand; i++, candp++) {
+        int32 start_score;
+
+        /* This can happen if recognition fails. */
+        if (candp->bp == -1)
+            continue;
+        /* Backpointer entry for it. */
+        bpe = &(ngs->bp_table[candp->bp]);
+
+        /* Subtract starting score for candidate, leave it with only word score */
+        start_score = ngram_search_exit_score
+            (ngs, bpe, dict_first_phone(ps_search_dict(ngs), candp->wid));
+        assert(start_score BETTER_THAN WORST_SCORE);
+        candp->score -= start_score;
+
+        /*
+         * If this candidate not occurred in an earlier frame, prepare for finding
+         * best transition score into last phone; sort by start frame.
+         */
+        /* i.e. if we don't have an entry in last_ltrans for this
+         * <word,sf>, then create one */
+        if (ngs->last_ltrans[candp->wid].sf != bpe->frame + 1) {
+            /* Look for an entry in cand_sf matching the backpointer
+             * for this candidate. */
+            for (j = 0; j < n_cand_sf; j++) {
+                if (ngs->cand_sf[j].bp_ef == bpe->frame)
+                    break;
+            }
+            /* Oh, we found one, so chain onto it. */
+            if (j < n_cand_sf)
+                candp->next = ngs->cand_sf[j].cand;
+            else {
+                /* Nope, let's make a new one, allocating cand_sf if necessary. */
+                if (n_cand_sf >= ngs->cand_sf_alloc) {
+                    if (ngs->cand_sf_alloc == 0) {
+                        ngs->cand_sf =
+                            ckd_calloc(CAND_SF_ALLOCSIZE,
+                                       sizeof(*ngs->cand_sf));
+                        ngs->cand_sf_alloc = CAND_SF_ALLOCSIZE;
+                    }
+                    else {
+                        ngs->cand_sf_alloc += CAND_SF_ALLOCSIZE;
+                        ngs->cand_sf = ckd_realloc(ngs->cand_sf,
+                                                   ngs->cand_sf_alloc
+                                                   * sizeof(*ngs->cand_sf));
+                        E_INFO("cand_sf[] increased to %d entries\n",
+                               ngs->cand_sf_alloc);
+                    }
+                }
+
+                /* Use the newly created cand_sf. */
+                j = n_cand_sf++;
+                candp->next = -1; /* End of the chain. */
+                ngs->cand_sf[j].bp_ef = bpe->frame;
+            }
+            /* Update it to point to this candidate. */
+            ngs->cand_sf[j].cand = i;
+
+            ngs->last_ltrans[candp->wid].dscr = WORST_SCORE;
+            ngs->last_ltrans[candp->wid].sf = bpe->frame + 1;
+        }
+    }
+
+    /* Compute best LM score and bp for new cands entered in the sorted lists above */
+    for (i = 0; i < n_cand_sf; i++) {
+        /* For the i-th unique end frame... */
+        bp = ngs->bp_table_idx[ngs->cand_sf[i].bp_ef];
+        bpend = ngs->bp_table_idx[ngs->cand_sf[i].bp_ef + 1];
+        for (bpe = &(ngs->bp_table[bp]); bp < bpend; bp++, bpe++) {
+            if (!bpe->valid)
+                continue;
+            /* For each candidate at the start frame find bp->cand transition-score */
+            for (j = ngs->cand_sf[i].cand; j >= 0; j = candp->next) {
+                int32 n_used;
+                candp = &(ngs->lastphn_cand[j]);
+                dscr = 
+                    ngram_search_exit_score
+                    (ngs, bpe, dict_first_phone(ps_search_dict(ngs), candp->wid));
+                if (dscr BETTER_THAN WORST_SCORE) {
+                    assert(!dict_filler_word(ps_search_dict(ngs), candp->wid));
+                    dscr += ngram_tg_score(ngs->lmset,
+                                           dict_basewid(ps_search_dict(ngs), candp->wid),
+                                           bpe->real_wid,
+                                           bpe->prev_real_wid,
+                                           &n_used)>>SENSCR_SHIFT;
+                }
+
+                if (dscr BETTER_THAN ngs->last_ltrans[candp->wid].dscr) {
+                    ngs->last_ltrans[candp->wid].dscr = dscr;
+                    ngs->last_ltrans[candp->wid].bp = bp;
+                }
+            }
+        }
+    }
+
+    /* Update best transitions for all candidates; also update best lastphone score */
+    bestscore = ngs->last_phone_best_score;
+    for (i = 0, candp = ngs->lastphn_cand; i < ngs->n_lastphn_cand; i++, candp++) {
+        candp->score += ngs->last_ltrans[candp->wid].dscr;
+        candp->bp = ngs->last_ltrans[candp->wid].bp;
+
+        if (candp->score BETTER_THAN bestscore)
+            bestscore = candp->score;
+    }
+    ngs->last_phone_best_score = bestscore;
+
+    /* At this pt, we know the best entry score (with LM component) for all candidates */
+    thresh = bestscore + ngs->lponlybeam;
+    for (i = ngs->n_lastphn_cand, candp = ngs->lastphn_cand; i > 0; --i, candp++) {
+        if (candp->score BETTER_THAN thresh) {
+            w = candp->wid;
+
+            ngram_search_alloc_all_rc(ngs, w);
+
+            k = 0;
+            for (hmm = ngs->word_chan[w]; hmm; hmm = hmm->next) {
+                if ((hmm_frame(&hmm->hmm) < frame_idx)
+                    || (candp->score BETTER_THAN hmm_in_score(&hmm->hmm))) {
+                    assert(hmm_frame(&hmm->hmm) != nf);
+                    hmm_enter(&hmm->hmm,
+                              candp->score, candp->bp, nf);
+                    k++;
+                }
+            }
+            if (k > 0) {
+                assert(bitvec_is_clear(ngs->word_active, w));
+                assert(!dict_is_single_phone(ps_search_dict(ngs), w));
+                *(nawl++) = w;
+                bitvec_set(ngs->word_active, w);
+            }
+        }
+    }
+    ngs->n_active_word[nf & 0x1] = (int)(nawl - ngs->active_word_list[nf & 0x1]);
+}
+
+/*
+ * Prune currently active word channels for next frame.  Also, perform exit
+ * transitions out of such channels and active successors.
+ */
+static void
+prune_word_chan(ngram_search_t *ngs, int frame_idx)
+{
+    root_chan_t *rhmm;
+    chan_t *hmm, *thmm;
+    chan_t **phmmp;             /* previous HMM-pointer */
+    int32 nf, w, i, k;
+    int32 newword_thresh, lastphn_thresh;
+    int32 *awl, *nawl;
+
+    nf = frame_idx + 1;
+    newword_thresh = ngs->last_phone_best_score + ngs->wbeam;
+    lastphn_thresh = ngs->last_phone_best_score + ngs->lponlybeam;
+
+    awl = ngs->active_word_list[frame_idx & 0x1];
+    nawl = ngs->active_word_list[nf & 0x1] + ngs->n_active_word[nf & 0x1];
+
+    /* Dynamically allocated last channels of multi-phone words */
+    for (i = ngs->n_active_word[frame_idx & 0x1], w = *(awl++); i > 0;
+         --i, w = *(awl++)) {
+        k = 0;
+        phmmp = &(ngs->word_chan[w]);
+        for (hmm = ngs->word_chan[w]; hmm; hmm = thmm) {
+            assert(hmm_frame(&hmm->hmm) >= frame_idx);
+
+            thmm = hmm->next;
+            if (hmm_bestscore(&hmm->hmm) BETTER_THAN lastphn_thresh) {
+                /* retain this channel in next frame */
+                hmm_frame(&hmm->hmm) = nf;
+                k++;
+                phmmp = &(hmm->next);
+
+                /* Could if ((! skip_alt_frm) || (frame_idx & 0x1)) the following */
+                if (hmm_out_score(&hmm->hmm) BETTER_THAN newword_thresh) {
+                    /* can exit channel and recognize word */
+                    ngram_search_save_bp(ngs, frame_idx, w,
+                                 hmm_out_score(&hmm->hmm),
+                                 hmm_out_history(&hmm->hmm),
+                                 hmm->info.rc_id);
+                }
+            }
+            else if (hmm_frame(&hmm->hmm) == nf) {
+                phmmp = &(hmm->next);
+            }
+            else {
+                hmm_deinit(&hmm->hmm);
+                listelem_free(ngs->chan_alloc, hmm);
+                *phmmp = thmm;
+            }
+        }
+        if ((k > 0) && (bitvec_is_clear(ngs->word_active, w))) {
+            assert(!dict_is_single_phone(ps_search_dict(ngs), w));
+            *(nawl++) = w;
+            bitvec_set(ngs->word_active, w);
+        }
+    }
+    ngs->n_active_word[nf & 0x1] = (int)(nawl - ngs->active_word_list[nf & 0x1]);
+
+    /*
+     * Prune permanently allocated single-phone channels.
+     * NOTES: score[] of pruned channels set to WORST_SCORE elsewhere.
+     */
+    for (i = 0; i < ngs->n_1ph_words; i++) {
+        w = ngs->single_phone_wid[i];
+        rhmm = (root_chan_t *) ngs->word_chan[w];
+        E_DEBUG(3,("Single phone word %s frame %d score %d thresh %d outscore %d nwthresh %d\n",
+                   dict_wordstr(ps_search_dict(ngs),w),
+                   hmm_frame(&rhmm->hmm), hmm_bestscore(&rhmm->hmm),
+                   lastphn_thresh, hmm_out_score(&rhmm->hmm), newword_thresh));
+        if (hmm_frame(&rhmm->hmm) < frame_idx)
+            continue;
+        if (hmm_bestscore(&rhmm->hmm) BETTER_THAN lastphn_thresh) {
+            hmm_frame(&rhmm->hmm) = nf;
+
+            /* Could if ((! skip_alt_frm) || (frame_idx & 0x1)) the following */
+            if (hmm_out_score(&rhmm->hmm) BETTER_THAN newword_thresh) {
+                E_DEBUG(4,("Exiting single phone word %s with %d > %d, %d\n",
+                           dict_wordstr(ps_search_dict(ngs),w),
+                           hmm_out_score(&rhmm->hmm),
+                           lastphn_thresh, newword_thresh));
+                ngram_search_save_bp(ngs, frame_idx, w,
+                             hmm_out_score(&rhmm->hmm),
+                             hmm_out_history(&rhmm->hmm), 0);
+            }
+        }
+    }
+}
+
+static void
+prune_channels(ngram_search_t *ngs, int frame_idx)
+{
+    /* Clear last phone candidate list. */
+    ngs->n_lastphn_cand = 0;
+    /* Set the dynamic beam based on maxhmmpf here. */
+    ngs->dynamic_beam = ngs->beam;
+    if (ngs->maxhmmpf != -1
+        && ngs->st.n_root_chan_eval + ngs->st.n_nonroot_chan_eval > ngs->maxhmmpf) {
+        /* Build a histogram to approximately prune them. */
+        int32 bins[256], bw, nhmms, i;
+        root_chan_t *rhmm;
+        chan_t **acl, *hmm;
+
+        /* Bins go from zero (best score) to edge of beam. */
+        bw = -ngs->beam / 256;
+        memset(bins, 0, sizeof(bins));
+        /* For each active root channel. */
+        for (i = 0, rhmm = ngs->root_chan; i < ngs->n_root_chan; i++, rhmm++) {
+            int32 b;
+
+            /* Put it in a bin according to its bestscore. */
+            b = (ngs->best_score - hmm_bestscore(&rhmm->hmm)) / bw;
+            if (b >= 256)
+                b = 255;
+            ++bins[b];
+        }
+        /* For each active non-root channel. */
+        acl = ngs->active_chan_list[frame_idx & 0x1];       /* currently active HMMs in tree */
+        for (i = ngs->n_active_chan[frame_idx & 0x1], hmm = *(acl++);
+             i > 0; --i, hmm = *(acl++)) {
+            int32 b;
+
+            /* Put it in a bin according to its bestscore. */
+            b = (ngs->best_score - hmm_bestscore(&hmm->hmm)) / bw;
+            if (b >= 256)
+                b = 255;
+            ++bins[b];
+        }
+        /* Walk down the bins to find the new beam. */
+        for (i = nhmms = 0; i < 256; ++i) {
+            nhmms += bins[i];
+            if (nhmms > ngs->maxhmmpf)
+                break;
+        }
+        ngs->dynamic_beam = -(i * bw);
+    }
+
+    prune_root_chan(ngs, frame_idx);
+    prune_nonroot_chan(ngs, frame_idx);
+    last_phone_transition(ngs, frame_idx);
+    prune_word_chan(ngs, frame_idx);
+}
+
+/*
+ * Limit the number of word exits in each frame to maxwpf.  And also limit the number of filler
+ * words to 1.
+ */
+static void
+bptable_maxwpf(ngram_search_t *ngs, int frame_idx)
+{
+    int32 bp, n;
+    int32 bestscr, worstscr;
+    bptbl_t *bpe, *bestbpe, *worstbpe;
+
+    /* Don't prune if no pruing. */
+    if (ngs->maxwpf == -1 || ngs->maxwpf == ps_search_n_words(ngs))
+        return;
+
+    /* Allow only one filler word exit (the best) per frame */
+    bestscr = (int32) 0x80000000;
+    bestbpe = NULL;
+    n = 0;
+    for (bp = ngs->bp_table_idx[frame_idx]; bp < ngs->bpidx; bp++) {
+        bpe = &(ngs->bp_table[bp]);
+        if (dict_filler_word(ps_search_dict(ngs), bpe->wid)) {
+            if (bpe->score BETTER_THAN bestscr) {
+                bestscr = bpe->score;
+                bestbpe = bpe;
+            }
+            bpe->valid = FALSE;
+            n++;                /* No. of filler words */
+        }
+    }
+    /* Restore bestbpe to valid state */
+    if (bestbpe != NULL) {
+        bestbpe->valid = TRUE;
+        --n;
+    }
+
+    /* Allow up to maxwpf best entries to survive; mark the remaining with valid = 0 */
+    n = (ngs->bpidx
+         - ngs->bp_table_idx[frame_idx]) - n;  /* No. of entries after limiting fillers */
+    for (; n > ngs->maxwpf; --n) {
+        /* Find worst BPTable entry */
+        worstscr = (int32) 0x7fffffff;
+        worstbpe = NULL;
+        for (bp = ngs->bp_table_idx[frame_idx]; (bp < ngs->bpidx); bp++) {
+            bpe = &(ngs->bp_table[bp]);
+            if (bpe->valid && (bpe->score WORSE_THAN worstscr)) {
+                worstscr = bpe->score;
+                worstbpe = bpe;
+            }
+        }
+        /* FIXME: Don't panic! */
+        if (worstbpe == NULL)
+            E_FATAL("PANIC: No worst BPtable entry remaining\n");
+        worstbpe->valid = FALSE;
+    }
+}
+
+static void
+word_transition(ngram_search_t *ngs, int frame_idx)
+{
+    int32 i, k, bp, w, nf;
+    int32 rc;
+    int32 thresh, newscore, pl_newscore;
+    bptbl_t *bpe;
+    root_chan_t *rhmm;
+    struct bestbp_rc_s *bestbp_rc_ptr;
+    phone_loop_search_t *pls;
+    dict_t *dict = ps_search_dict(ngs);
+    dict2pid_t *d2p = ps_search_dict2pid(ngs);
+
+    /*
+     * Transition to start of new word instances (HMM tree roots); but only if words
+     * other than </s> finished here.
+     * But, first, find the best starting score for each possible right context phone.
+     */
+    for (i = bin_mdef_n_ciphone(ps_search_acmod(ngs)->mdef) - 1; i >= 0; --i)
+        ngs->bestbp_rc[i].score = WORST_SCORE;
+    k = 0;
+    pls = (phone_loop_search_t *)ps_search_lookahead(ngs);
+    /* Ugh, this is complicated.  Scan all word exits for this frame
+     * (they have already been created by prune_word_chan()). */
+    for (bp = ngs->bp_table_idx[frame_idx]; bp < ngs->bpidx; bp++) {
+        bpe = &(ngs->bp_table[bp]);
+        ngs->word_lat_idx[bpe->wid] = NO_BP;
+
+        if (bpe->wid == ps_search_finish_wid(ngs))
+            continue;
+        k++;
+
+        /* DICT2PID */
+        /* Array of HMM scores corresponding to all the possible right
+         * context expansions of the final phone.  It's likely that a
+         * lot of these are going to be missing, actually. */
+        if (bpe->last2_phone == -1) { /* implies s_idx == -1 */
+            /* No right context expansion. */
+            for (rc = 0; rc < bin_mdef_n_ciphone(ps_search_acmod(ngs)->mdef); ++rc) {
+                if (bpe->score BETTER_THAN ngs->bestbp_rc[rc].score) {
+                    E_DEBUG(4,("bestbp_rc[0] = %d lc %d\n",
+                               bpe->score, bpe->last_phone));
+                    ngs->bestbp_rc[rc].score = bpe->score;
+                    ngs->bestbp_rc[rc].path = bp;
+                    ngs->bestbp_rc[rc].lc = bpe->last_phone;
+                }
+            }
+        }
+        else {
+            xwdssid_t *rssid = dict2pid_rssid(d2p, bpe->last_phone, bpe->last2_phone);
+            int32 *rcss = &(ngs->bscore_stack[bpe->s_idx]);
+            for (rc = 0; rc < bin_mdef_n_ciphone(ps_search_acmod(ngs)->mdef); ++rc) {
+                if (rcss[rssid->cimap[rc]] BETTER_THAN ngs->bestbp_rc[rc].score) {
+                    E_DEBUG(4,("bestbp_rc[%d] = %d lc %d\n",
+                               rc, rcss[rssid->cimap[rc]], bpe->last_phone));
+                    ngs->bestbp_rc[rc].score = rcss[rssid->cimap[rc]];
+                    ngs->bestbp_rc[rc].path = bp;
+                    ngs->bestbp_rc[rc].lc = bpe->last_phone;
+                }
+            }
+        }
+    }
+    if (k == 0)
+        return;
+
+    nf = frame_idx + 1;
+    thresh = ngs->best_score + ngs->dynamic_beam;
+    /*
+     * Hypothesize successors to words finished in this frame.
+     * Main dictionary, multi-phone words transition to HMM-trees roots.
+     */
+    for (i = ngs->n_root_chan, rhmm = ngs->root_chan; i > 0; --i, rhmm++) {
+        bestbp_rc_ptr = &(ngs->bestbp_rc[rhmm->ciphone]);
+
+        newscore = bestbp_rc_ptr->score + ngs->nwpen + ngs->pip;
+        pl_newscore = newscore
+            + phone_loop_search_score(pls, rhmm->ciphone);
+        if (pl_newscore BETTER_THAN thresh) {
+            if ((hmm_frame(&rhmm->hmm) < frame_idx)
+                || (newscore BETTER_THAN hmm_in_score(&rhmm->hmm))) {
+                hmm_enter(&rhmm->hmm, newscore,
+                          bestbp_rc_ptr->path, nf);
+                /* DICT2PID: Another place where mpx ssids are entered. */
+                /* 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, bestbp_rc_ptr->lc);
+                assert(hmm_mpx_ssid(&rhmm->hmm, 0) != BAD_SSID);
+            }
+        }
+    }
+
+    /*
+     * Single phone words; no right context for these.  Cannot use bestbp_rc as
+     * LM scores have to be included.  First find best transition to these words.
+     */
+    for (i = 0; i < ngs->n_1ph_LMwords; i++) {
+        w = ngs->single_phone_wid[i];
+        ngs->last_ltrans[w].dscr = (int32) 0x80000000;
+    }
+    for (bp = ngs->bp_table_idx[frame_idx]; bp < ngs->bpidx; bp++) {
+        bpe = &(ngs->bp_table[bp]);
+        if (!bpe->valid)
+            continue;
+
+        for (i = 0; i < ngs->n_1ph_LMwords; i++) {
+            int32 n_used;
+            w = ngs->single_phone_wid[i];
+            newscore = ngram_search_exit_score
+                (ngs, bpe, dict_first_phone(dict, w));
+            E_DEBUG(4, ("initial newscore for %s: %d\n",
+                        dict_wordstr(dict, w), newscore));
+            if (newscore != WORST_SCORE)
+                newscore += ngram_tg_score(ngs->lmset,
+                                           dict_basewid(dict, w),
+                                           bpe->real_wid,
+                                           bpe->prev_real_wid,
+                                           &n_used)>>SENSCR_SHIFT;
+
+            /* FIXME: Not sure how WORST_SCORE could be better, but it
+             * apparently happens. */
+            if (newscore BETTER_THAN ngs->last_ltrans[w].dscr) {
+                ngs->last_ltrans[w].dscr = newscore;
+                ngs->last_ltrans[w].bp = bp;
+            }
+        }
+    }
+
+    /* Now transition to in-LM single phone words */
+    for (i = 0; i < ngs->n_1ph_LMwords; i++) {
+        w = ngs->single_phone_wid[i];
+        /* Never transition into the start word (for one thing, it is
+           a non-event in the language model.) */
+        if (w == dict_startwid(ps_search_dict(ngs)))
+            continue;
+        rhmm = (root_chan_t *) ngs->word_chan[w];
+        newscore = ngs->last_ltrans[w].dscr + ngs->pip;
+	pl_newscore = newscore + phone_loop_search_score(pls, rhmm->ciphone);
+        if (pl_newscore BETTER_THAN thresh) {
+            bpe = ngs->bp_table + ngs->last_ltrans[w].bp;
+            if ((hmm_frame(&rhmm->hmm) < frame_idx)
+                || (newscore BETTER_THAN hmm_in_score(&rhmm->hmm))) {
+                hmm_enter(&rhmm->hmm,
+                          newscore, ngs->last_ltrans[w].bp, nf);
+                /* DICT2PID: another place where mpx ssids are entered. */
+                /* 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, bpe->wid));
+                assert(hmm_mpx_ssid(&rhmm->hmm, 0) != BAD_SSID);
+            }
+        }
+    }
+
+    /* Remaining words: <sil>, noise words.  No mpx for these! */
+    w = ps_search_silence_wid(ngs);
+    rhmm = (root_chan_t *) ngs->word_chan[w];
+    bestbp_rc_ptr = &(ngs->bestbp_rc[ps_search_acmod(ngs)->mdef->sil]);
+    newscore = bestbp_rc_ptr->score + ngs->silpen + ngs->pip;
+    pl_newscore = newscore
+        + phone_loop_search_score(pls, rhmm->ciphone);
+    if (pl_newscore BETTER_THAN thresh) {
+        if ((hmm_frame(&rhmm->hmm) < frame_idx)
+            || (newscore BETTER_THAN hmm_in_score(&rhmm->hmm))) {
+            hmm_enter(&rhmm->hmm,
+                      newscore, bestbp_rc_ptr->path, nf);
+        }
+    }
+    for (w = dict_filler_start(dict); w <= dict_filler_end(dict); w++) {
+        if (w == ps_search_silence_wid(ngs))
+            continue;
+        /* Never transition into the start word (for one thing, it is
+           a non-event in the language model.) */
+        if (w == dict_startwid(ps_search_dict(ngs)))
+            continue;
+        rhmm = (root_chan_t *) ngs->word_chan[w];
+        /* If this was not actually a single-phone word, rhmm will be NULL. */
+        if (rhmm == NULL)
+            continue;
+        newscore = bestbp_rc_ptr->score + ngs->fillpen + ngs->pip;
+        pl_newscore = newscore
+            + phone_loop_search_score(pls, rhmm->ciphone);
+        if (pl_newscore BETTER_THAN thresh) {
+            if ((hmm_frame(&rhmm->hmm) < frame_idx)
+                || (newscore BETTER_THAN hmm_in_score(&rhmm->hmm))) {
+                hmm_enter(&rhmm->hmm,
+                          newscore, bestbp_rc_ptr->path, nf);
+            }
+        }
+    }
+}
+
+static void
+deactivate_channels(ngram_search_t *ngs, int frame_idx)
+{
+    root_chan_t *rhmm;
+    int i;
+
+    /* Clear score[] of pruned root channels */
+    for (i = ngs->n_root_chan, rhmm = ngs->root_chan; i > 0; --i, rhmm++) {
+        if (hmm_frame(&rhmm->hmm) == frame_idx) {
+            hmm_clear(&rhmm->hmm);
+        }
+    }
+    /* Clear score[] of pruned single-phone channels */
+    for (i = 0; i < ngs->n_1ph_words; i++) {
+        int32 w = ngs->single_phone_wid[i];
+        rhmm = (root_chan_t *) ngs->word_chan[w];
+        if (hmm_frame(&rhmm->hmm) == frame_idx) {
+            hmm_clear(&rhmm->hmm);
+        }
+    }
+}
+
+int
+ngram_fwdtree_search(ngram_search_t *ngs, int frame_idx)
+{
+    int16 const *senscr;
+
+    /* Activate our HMMs for the current frame if need be. */
+    if (!ps_search_acmod(ngs)->compallsen)
+        compute_sen_active(ngs, frame_idx);
+
+    /* Compute GMM scores for the current frame. */
+    if ((senscr = acmod_score(ps_search_acmod(ngs), &frame_idx)) == NULL)
+        return 0;
+    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);
+        renormalize_scores(ngs, frame_idx, ngs->best_score);
+    }
+
+    /* Evaluate HMMs */
+    evaluate_channels(ngs, senscr, frame_idx);
+    /* Prune HMMs and do phone transitions. */
+    prune_channels(ngs, frame_idx);
+    /* Do absolute pruning on word exits. */
+    bptable_maxwpf(ngs, frame_idx);
+    /* Do word transitions. */
+    word_transition(ngs, frame_idx);
+    /* Deactivate pruned HMMs. */
+    deactivate_channels(ngs, frame_idx);
+
+    ++ngs->n_frame;
+    /* Return the number of frames processed. */
+    return 1;
+}
+
+void
+ngram_fwdtree_finish(ngram_search_t *ngs)
+{
+    int32 i, w, cf, *awl;
+    root_chan_t *rhmm;
+    chan_t *hmm, **acl;
+
+    /* 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);
+
+    /* Deactivate channels lined up for the next frame */
+    /* First, root channels of HMM tree */
+    for (i = ngs->n_root_chan, rhmm = ngs->root_chan; i > 0; --i, rhmm++) {
+        hmm_clear(&rhmm->hmm);
+    }
+
+    /* nonroot channels of HMM tree */
+    i = ngs->n_active_chan[cf & 0x1];
+    acl = ngs->active_chan_list[cf & 0x1];
+    for (hmm = *(acl++); i > 0; --i, hmm = *(acl++)) {
+        hmm_clear(&hmm->hmm);
+    }
+
+    /* word channels */
+    i = ngs->n_active_word[cf & 0x1];
+    awl = ngs->active_word_list[cf & 0x1];
+    for (w = *(awl++); i > 0; --i, w = *(awl++)) {
+        /* Don't accidentally free single-phone words! */
+        if (dict_is_single_phone(ps_search_dict(ngs), w))
+            continue;
+        bitvec_clear(ngs->word_active, w);
+        if (ngs->word_chan[w] == NULL)
+            continue;
+        ngram_search_free_all_rc(ngs, w);
+    }
+
+    /*
+     * The previous search code did a postprocessing of the
+     * backpointer table here, but we will postpone this until it is
+     * absolutely necessary, i.e. when generating a word graph.
+     * Likewise we don't actually have to decide what the exit word is
+     * until somebody requests a backtrace.
+     */
+
+    ptmr_stop(&ngs->fwdtree_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), %d 1st, %d last\n",
+               ngs->st.n_root_chan_eval + ngs->st.n_nonroot_chan_eval,
+               (ngs->st.n_root_chan_eval + ngs->st.n_nonroot_chan_eval) / (cf + 1),
+               ngs->st.n_root_chan_eval, ngs->st.n_last_chan_eval);
+        E_INFO("%8d words for which last channels evaluated (%d/fr)\n",
+               ngs->st.n_word_lastchan_eval,
+               ngs->st.n_word_lastchan_eval / (cf + 1));
+        E_INFO("%8d candidate words for entering last phone (%d/fr)\n",
+               ngs->st.n_lastphn_cand_utt, ngs->st.n_lastphn_cand_utt / (cf + 1));
+        E_INFO("fwdtree %.2f CPU %.3f xRT\n",
+               ngs->fwdtree_perf.t_cpu,
+               ngs->fwdtree_perf.t_cpu / n_speech);
+        E_INFO("fwdtree %.2f wall %.3f xRT\n",
+               ngs->fwdtree_perf.t_elapsed,
+               ngs->fwdtree_perf.t_elapsed / n_speech);
+    }
+    /* dump_bptable(ngs); */
+}