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

/* 
 * public/ann/annfunc/hyperbola_tangent.c 
 * 2004-05-03 by ShanLanshan 
 */ 
#include "public/ann/annfunc/annfunc.h" 
#include "public/ann/annfunc/hyperbola_tangent.h" 
 
namespace ann { 
namespace annfunc { 
namespace hyperbola_tangent { 
 
	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 = { 
		"hyperbola_tangent", 
		"双曲正切函数", 
		init, 
		finalize, 
		main_func, 
		derivative_func, 
		derivative_func2, 
		multi_main_func, 
		multi_derivative_func, 
		multi_derivative_func2 
	}; 
 
	static bool init() 
	{ 
		return true; 
	} 
 
	static void finalize() {} 
 
	/*  
	 * 双曲正切函数  
	 * w = (1- e ^ (-f)) / ( 1 + e ^ (-f)) 
	 */ 
	static ann_float main_func(ann_float f) 
	{ 
		ann_float u; 
		u = pow(E, -f); 
		return (1 - u) / (1 + u); 
	} 
 
	/*  
	 * 双曲正切函数的导数 
	 * 
	 * 	w = (1- e ^ (-f)) / ( 1 + e ^ (-f)); 
	 * 	Let u(f) = e ^ (-f), => @u/@f = - e ^ (-f) = -u 
	 * 	@w/@f = (@w/@u) * (@u/@f) 
	 * 	w = (1 - u) / (1 + u) 
	 * 	@w/@u = (-1 * (1 + u) - (1 - u) * 1) / (( 1 + u ) ^ 2) 
	 * 	      = -2 / ((1 + u) ^ 2); 
	 *	@w/@f = 2u / ((1 + u) ^ 2) 
	 */ 
	static ann_float derivative_func(ann_float f) 
	{ 
		ann_float u; 
		u = pow(E, -f); 
		return 2 * u / ((1 + u) * (1 + u)); 
	} 
 
	/*  
	 * 求双曲正切函数的导数值，输入的参数是主函数的值 
	 * 	Let u(f) = e ^ (-f) 
	 * 	w = (1 - u) / (1 + u) 
	 *	@w/@f = 2u / ((1 + u) ^ 2) 
	 *	      = 0.5 * ((1 + u) ^ 2 - (1 - u) ^ 2) / ((1 + u) ^ 2) 
	 *	      = 0.5 * (1 - (((1 - u) ^ 2)/((1 + u) ^ 2))) 
	 *	      = 0.5 * (1 - w ^ 2) 
	 */ 
	static ann_float derivative_func2(ann_float f) 
	{ 
		return (1 - f * f) / 2; 
	} 
 
	static void multi_main_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