www.pudn.com > bp_cpp.zip > sign.cpp

/* 
 * public/ann/annfunc/sign.c 
 * 2004-05-03 by ShanLanshan 
 */ 
#include "public/ann/annfunc/annfunc.h" 
#include "public/ann/annfunc/sign.h" 
 
namespace ann { 
namespace annfunc { 
namespace sign { 
 
	static bool init(); 
	static void finalize(); 
	static ann_float main_func(ann_float f); 
	static ann_float derivative_func(ann_float f); 
	static ann_float derivative_func2(ann_float f); 
	static void multi_main_func(ann_float *src, ann_int len, ann_float *dst); 
	static void multi_derivative_func(ann_float *src, ann_int len, ann_float *dst); 
	static void multi_derivative_func2(ann_float *src, ann_int len, ann_float *dst); 
 
	extern  AnnFuncGroup g_funcgroup = { 
		"sign", 
		"符号函数", 
		init, 
		finalize, 
		main_func, 
		derivative_func, 
		NULL, 
		multi_main_func, 
		multi_derivative_func, 
		NULL 
	}; 
 
	static bool init() 
	{ 
		return true; 
	} 
 
	static void finalize() {} 
 
	/*  
	 * 符号函数  
	 * w = 1 / ( 1 + e ^ (-f)) 
	 */ 
	static ann_float main_func(ann_float f) 
	{ 
		if (f >= 0.0) 
			return 1; 
		else 
			return -1; 
	} 
 
	/* 
	 * 符号函数的导数 
	 * 符号函数是不可导的，我们把它当作双曲正切函数看 
	 */ 
	static ann_float derivative_func(ann_float f) 
	{ 
		ann_float u; 
		u = pow(E, -f); 
		return 2 * u / ((1 + u) * (1 + u)); 
	} 
 
	static void multi_main_func(ann_float *src, ann_int len, ann_float *dst) 
	{ 
		ann_float f; 
 
		assert(src != NULL); 
		if (dst == NULL) 
			dst = src; 
 
		for (int i=0; i= 0.0 ? 1 : -1; 
		} 
	} 
	 
	static void multi_derivative_func(ann_float *src, ann_int len, ann_float *dst) 
	{ 
		ann_float u, f; 
 
		assert(src != NULL); 
		if (dst == NULL) 
			dst = src; 
 
		for (int i=0; i