1/* Copyright (c) 2008-2011 Octasic Inc.
2   Written by Jean-Marc Valin */
3/*
4   Redistribution and use in source and binary forms, with or without
5   modification, are permitted provided that the following conditions
6   are met:
7
8   - Redistributions of source code must retain the above copyright
9   notice, this list of conditions and the following disclaimer.
10
11   - Redistributions in binary form must reproduce the above copyright
12   notice, this list of conditions and the following disclaimer in the
13   documentation and/or other materials provided with the distribution.
14
15   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
19   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
23   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
24   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26*/
27
28#ifndef _MLP_TRAIN_H_
29#define _MLP_TRAIN_H_
30
31#include <math.h>
32#include <stdlib.h>
33
34double tansig_table[501];
35static inline double tansig_double(double x)
36{
37	return 2./(1.+exp(-2.*x)) - 1.;
38}
39static inline void build_tansig_table()
40{
41	int i;
42	for (i=0;i<501;i++)
43		tansig_table[i] = tansig_double(.04*(i-250));
44}
45
46static inline double tansig_approx(double x)
47{
48	int i;
49	double y, dy;
50	if (x>=10)
51		return 1;
52	if (x<=-10)
53		return -1;
54	i = lrint(25*x);
55	x -= .04*i;
56	y = tansig_table[250+i];
57	dy = 1-y*y;
58	y = y + x*dy*(1 - y*x);
59	return y;
60}
61
62inline float randn(float sd)
63{
64   float U1, U2, S, x;
65   do {
66      U1 = ((float)rand())/RAND_MAX;
67      U2 = ((float)rand())/RAND_MAX;
68      U1 = 2*U1-1;
69      U2 = 2*U2-1;
70      S = U1*U1 + U2*U2;
71   } while (S >= 1 || S == 0.0f);
72   x = sd*sqrt(-2 * log(S) / S) * U1;
73   return x;
74}
75
76
77typedef struct {
78	int layers;
79	int *topo;
80	double **weights;
81	double **best_weights;
82	double *in_rate;
83} MLPTrain;
84
85
86#endif /* _MLP_TRAIN_H_ */
87