/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */ /* ==================================================================== * Copyright (c) 1999-2004 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 hmm.h Hidden Markov Model base structures. */ #ifndef __HMM_H__ #define __HMM_H__ /* System headers. */ #include <stdio.h> /* SphinxBase headers. */ #include <sphinxbase/fixpoint.h> #include <sphinxbase/listelem_alloc.h> /* PocketSphinx headers. */ #include "bin_mdef.h" #ifdef __cplusplus extern "C" { #endif /** * Type for frame index values. Used in HMM indexes and * backpointers and affects memory required.Due to limitations of FSG * search implementation this value needs to be signed. */ typedef int32 frame_idx_t; /** * Maximum number of frames in index, should be in sync with above. */ #define MAX_N_FRAMES MAX_INT32 /** Shift count for senone scores. */ #define SENSCR_SHIFT 10 /** * Large "bad" score. * * This number must be "bad" enough so that 4 times WORST_SCORE will * not overflow. The reason for this is that the search doesn't check * the scores in a model before evaluating the model and it may * require as many was 4 plies before the new 'good' score can wipe * out the initial WORST_SCORE initialization. */ #define WORST_SCORE ((int)0xE0000000) /** * Watch out, though! Transition matrix entries that are supposed to * be "zero" don't actually get that small due to quantization. */ #define TMAT_WORST_SCORE (-255) /** * Is one score better than another? */ #define BETTER_THAN > /** * Is one score worse than another? */ #define WORSE_THAN < /** \file hmm.h * \brief HMM data structure and operation * * For efficiency, this version is hardwired for two possible HMM * topologies, but will fall back to others: * * 5-state left-to-right HMMs: (0 is the *emitting* entry state and E * is a non-emitting exit state; the x's indicate allowed transitions * between source and destination states): * * <pre> * 0 1 2 3 4 E (destination-states) * 0 x x x * 1 x x x * 2 x x x * 3 x x x * 4 x x * (source-states) * </pre> * * 5-state topologies that contain a subset of the above transitions should work as well. * * 3-state left-to-right HMMs (similar notation as the 5-state topology above): * * <pre> * 0 1 2 E (destination-states) * 0 x x x * 1 x x x * 2 x x * (source-states) * </pre> * * 3-state topologies that contain a subset of the above transitions should work as well. */ /** * @struct hmm_context_t * @brief Shared information between a set of HMMs. * * We assume that the initial state is emitting and that the * transition matrix is n_emit_state x (n_emit_state+1), where the * extra destination dimension correponds to the non-emitting final or * exit state. */ typedef struct hmm_context_s { int32 n_emit_state; /**< Number of emitting states in this set of HMMs. */ uint8 ** const *tp; /**< State transition scores tp[id][from][to] (logs3 values). */ int16 const *senscore; /**< State emission scores senscore[senid] (negated scaled logs3 values). */ uint16 * const *sseq; /**< Senone sequence mapping. */ int32 *st_sen_scr; /**< Temporary array of senone scores (for some topologies). */ listelem_alloc_t *mpx_ssid_alloc; /**< Allocator for senone sequence ID arrays. */ void *udata; /**< Whatever you feel like, gosh. */ } hmm_context_t; /** * Hard-coded limit on the number of emitting states. */ #define HMM_MAX_NSTATE 5 /** * @struct hmm_t * @brief An individual HMM among the HMM search space. * * An individual HMM among the HMM search space. An HMM with N * emitting states consists of N+1 internal states including the * non-emitting exit (out) state. */ typedef struct hmm_s { hmm_context_t *ctx; /**< Shared context data for this HMM. */ int32 score[HMM_MAX_NSTATE]; /**< State scores for emitting states. */ int32 history[HMM_MAX_NSTATE]; /**< History indices for emitting states. */ int32 out_score; /**< Score for non-emitting exit state. */ int32 out_history; /**< History index for non-emitting exit state. */ uint16 ssid; /**< Senone sequence ID (for non-MPX) */ uint16 senid[HMM_MAX_NSTATE]; /**< Senone IDs (non-MPX) or sequence IDs (MPX) */ int32 bestscore; /**< Best [emitting] state score in current frame (for pruning). */ int16 tmatid; /**< Transition matrix ID (see hmm_context_t). */ frame_idx_t frame; /**< Frame in which this HMM was last active; <0 if inactive */ uint8 mpx; /**< Is this HMM multiplex? (hoisted for speed) */ uint8 n_emit_state; /**< Number of emitting states (hoisted for speed) */ } hmm_t; /** Access macros. */ #define hmm_context(h) (h)->ctx #define hmm_is_mpx(h) (h)->mpx #define hmm_in_score(h) (h)->score[0] #define hmm_score(h,st) (h)->score[st] #define hmm_out_score(h) (h)->out_score #define hmm_in_history(h) (h)->history[0] #define hmm_history(h,st) (h)->history[st] #define hmm_out_history(h) (h)->out_history #define hmm_bestscore(h) (h)->bestscore #define hmm_frame(h) (h)->frame #define hmm_mpx_ssid(h,st) (h)->senid[st] #define hmm_nonmpx_ssid(h) (h)->ssid #define hmm_ssid(h,st) (hmm_is_mpx(h) \ ? hmm_mpx_ssid(h,st) : hmm_nonmpx_ssid(h)) #define hmm_mpx_senid(h,st) (hmm_mpx_ssid(h,st) == BAD_SENID \ ? BAD_SENID : (h)->ctx->sseq[hmm_mpx_ssid(h,st)][st]) #define hmm_nonmpx_senid(h,st) ((h)->senid[st]) #define hmm_senid(h,st) (hmm_is_mpx(h) \ ? hmm_mpx_senid(h,st) : hmm_nonmpx_senid(h,st)) #define hmm_senscr(h,st) (hmm_senid(h,st) == BAD_SENID \ ? WORST_SCORE \ : -(h)->ctx->senscore[hmm_senid(h,st)]) #define hmm_tmatid(h) (h)->tmatid #define hmm_tprob(h,i,j) (-(h)->ctx->tp[hmm_tmatid(h)][i][j]) #define hmm_n_emit_state(h) ((h)->n_emit_state) #define hmm_n_state(h) ((h)->n_emit_state + 1) /** * Create an HMM context. **/ hmm_context_t *hmm_context_init(int32 n_emit_state, uint8 ** const *tp, int16 const *senscore, uint16 * const *sseq); /** * Change the senone score array for a context. **/ #define hmm_context_set_senscore(ctx, senscr) ((ctx)->senscore = (senscr)) /** * Free an HMM context. * * @note The transition matrices, senone scores, and senone sequence * mapping are all assumed to be allocated externally, and will NOT be * freed by this function. **/ void hmm_context_free(hmm_context_t *ctx); /** * Populate a previously-allocated HMM structure, allocating internal data. **/ void hmm_init(hmm_context_t *ctx, hmm_t *hmm, int mpx, int ssid, int tmatid); /** * Free an HMM structure, releasing internal data (but not the HMM structure itself). */ void hmm_deinit(hmm_t *hmm); /** * Reset the states of the HMM to the invalid condition. * i.e., scores to WORST_SCORE and hist to undefined. */ void hmm_clear(hmm_t *h); /** * Reset the scores of the HMM. */ void hmm_clear_scores(hmm_t *h); /** * Renormalize the scores in this HMM based on the given best score. */ void hmm_normalize(hmm_t *h, int32 bestscr); /** * Enter an HMM with the given path score and history ID. **/ void hmm_enter(hmm_t *h, int32 score, int32 histid, int frame); /** * Viterbi evaluation of given HMM. * * @note If this module were being used for tracking state * segmentations, the dummy, non-emitting exit state would have to be * updated separately. In the Viterbi DP diagram, transitions to the * exit state occur from the current time; they are vertical * transitions. Hence they should be made only after the history has * been logged for the emitting states. But we're not bothered with * state segmentations, for now. So, we update the exit state as * well. */ int32 hmm_vit_eval(hmm_t *hmm); /** * Like hmm_vit_eval, but dump HMM state and relevant senscr to fp first, for debugging;. */ int32 hmm_dump_vit_eval(hmm_t *hmm, /**< In/Out: HMM being updated */ FILE *fp /**< An output file pointer */ ); /** * For debugging, dump the whole HMM out. */ void hmm_dump(hmm_t *h, /**< In/Out: HMM being updated */ FILE *fp /**< An output file pointer */ ); #ifdef __cplusplus } #endif #endif /* __HMM_H__ */