log_add.h File Reference

#include <qualia/core/common.h>
#include <math.h>

Include dependency graph for log_add.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	log1p(x)   log(1+(x))
#define	LOG_2_PI   1.83787706640934548355
#define	LOG_ZERO   -INF
#define	LOG_ONE   0
real	logAdd (real log_a, real log_b)
real	logSub (real log_a, real log_b)
	logSub(log_a,log_b) = log(a-b) More...

Macro Definition Documentation

#define log1p

(

x

)

log(1+(x))

#define LOG_2_PI   1.83787706640934548355

Some simple functions for log operations.

Author

Samy Bengio (bengi.nosp@m.o@id.nosp@m.iap.c.nosp@m.h)

#define LOG_ONE   0

#define LOG_ZERO   -INF

Function Documentation

real logAdd	(	real	log_a,
		real	log_b
	)

logAdd(log_a,log_b) = log(a+b) = log(exp(log_a)+exp(log_b)) but done in a smart way so that if log_a or log_b are large but not their difference the computation works correctly.

real logSub	(	real	log_a,
		real	log_b
	)

logSub(log_a,log_b) = log(a-b)