src/libpocketsphinx/tied_mgau_common.h File Reference

Common code shared between SC and PTM (tied-state) models. More...

#include <sphinxbase/logmath.h>
#include <sphinxbase/fixpoint.h>

Go to the source code of this file.

Defines
#define	MGAU_MIXW_VERSION   "1.0"
#define	MGAU_PARAM_VERSION   "1.0"
#define	NONE   -1
#define	WORST_DIST   (int32)(0x80000000)
#define	GMMSUB(a, b)   ((a)-(b))
	Subtract GMM component b (assumed to be positive) and saturate.
#define	GMMADD(a, b)   ((a)+(b))
#define	MIN(a, b)   ((a) < (b) ? (a) : (b))
#define	LOGMATH_INLINE   static
#define	MAX_NEG_MIXW   159
	Maximum negated mixture weight value.
#define	MAX_NEG_ASCR   96
	Maximum negated acoustic score value.
Functions
LOGMATH_INLINE int	fast_logmath_add (logmath_t *lmath, int mlx, int mly)
	Quickly log-add two negated log probabilities.

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Detailed Description

Common code shared between SC and PTM (tied-state) models.

Definition in file tied_mgau_common.h.

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Define Documentation

#define MAX_NEG_ASCR   96

Maximum negated acoustic score value.

Definition at line 85 of file tied_mgau_common.h.

#define MAX_NEG_MIXW   159

Maximum negated mixture weight value.

Definition at line 84 of file tied_mgau_common.h.

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Function Documentation

LOGMATH_INLINE int fast_logmath_add	(	logmath_t *	lmath,
		int	mlx,
		int	mly
	)

Quickly log-add two negated log probabilities.

Parameters:

lmath	The log-math object
mlx	A negative log probability (0 < mlx < 255)
mly	A negative log probability (0 < mly < 255)

Returns:

-log(exp(-mlx)+exp(-mly))

We can do some extra-fast log addition since we know that mixw+ascr is always less than 256 and hence x-y is also always less than 256. This relies on some cooperation from logmath_t which will never produce a logmath table smaller than 256 entries.

Note that the parameters are *negated* log probabilities (and hence, are positive numbers), as is the return value. This is the key to the "fastness" of this function.

Definition at line 105 of file tied_mgau_common.h.