1	#include<stdio.h>
     2	#include<math.h>
     3	#include<time.h>
     4	#include<stdlib.h>
     5	
     6	#define LAYER	3
     7	#define INPUT	2
     8	#define HIDDEN	2
     9	#define OUTPUT	1
    10	#define CTG		4
    11	
    12	#define ITERATIONS	10000
    13	
    14	#define ETA		1.50
    15	#define EPSILON	1.00
    16	#define WD		2.00
    17	#define MIN_ERR	0.00001
    18	
    19	#define ON		0.9
    20	#define OFF		0.1
    21	#define SMAX	15
    22	#define SMIN	-15
    23	#define MAX		0.99995
    24	#define MIN		0.00005
    25	
    26	#ifdef	_Cdecl
    27	#define	drand() ((double)(rand()+1)/RAND_MAX-0.5)
    28	#else
    29	#define	drand() ((double)(rand()+1)/RAND_MAX-0.5)
    30	#endif
    31	
    32	#define sq(x) (x)*(x)
    33	
    34	double 	i_lay[CTG][INPUT+1],
    35			h_lay[HIDDEN+1],
    36			o_lay[OUTPUT],
    37			teach[CTG][OUTPUT];
    38			
    39	double	ih_w[INPUT+1][HIDDEN],
    40			ho_w[HIDDEN+1][OUTPUT];
    41			
    42	double	h_del[HIDDEN],
    43			o_del[OUTPUT];
    44	
    45	extern double sigmoid();
    46	
    47	main(argc,argv)
    48		int	argc;
    49		char **argv;
    50	{
    51	  int	i,j,ite,ctg;
    52	  double err,sum;
    53	  srand((int)time((long *)0));
    54	  
    55	  /* ExOR Problem */
    56	  i_lay[0][0]=OFF; i_lay[0][1]=OFF; i_lay[0][2]=ON; teach[0][0]=OFF;
    57	  i_lay[1][0]=ON;  i_lay[1][1]=OFF; i_lay[1][2]=ON; teach[1][0]=ON;
    58	  i_lay[2][0]=OFF; i_lay[2][1]=ON;  i_lay[2][2]=ON; teach[2][0]=ON;
    59	  i_lay[3][0]=ON; i_lay[3][1]=ON;  i_lay[3][2]=ON; teach[3][0]=OFF;
    60	  
    61	  h_lay[HIDDEN]=ON;
    62	  
    63	  for(j=0;j<HIDDEN;j++)
    64	    for(i=0;i<=INPUT;i++)
    65	      ih_w[i][j]=WD*drand();
    66	  for(j=0;j<OUTPUT;j++)
    67	    for(i=0;i<=HIDDEN;i++)
    68	      ho_w[i][j]=WD*drand();
    69	  
    70	  for(ite=0;ite<=ITERATIONS; ite++){
    71	    for(ctg=0,err=0.;ctg<CTG;ctg++){
    72	      for(j=0;j<HIDDEN;j++){
    73		for(i=0,sum=0.;i<=INPUT;i++)
    74		  sum += i_lay[ctg][i]*ih_w[i][j];
    75		h_lay[j]=sigmoid(sum);
    76	      }
    77	      for(j=0;j<OUTPUT;j++){
    78		for(i=0,sum=0.;i<=HIDDEN;i++)
    79		  sum+=h_lay[i]*ho_w[i][j];
    80		o_lay[j]=sigmoid(sum);
    81	      }
    82	      for(i=0;i<OUTPUT;i++){
    83		err+=sq(teach[ctg][i]-o_lay[i])/2./(double)CTG;
    84		o_del[i]=EPSILON*(teach[ctg][i]-o_lay[i])*o_lay[i]*(1.-o_lay[i]);
    85	      }
    86	      for(j=0;j<=HIDDEN;j++){
    87		h_del[j]=0.;
    88		for(i=0;i<OUTPUT;i++)
    89		  h_del[j]+=o_del[i]*ho_w[j][i];
    90		h_del[j]*=EPSILON*h_lay[j]*(1.-h_lay[j]);
    91	      }
    92	      
    93	      for(j=0;j<=HIDDEN;j++)
    94		for(i=0;i<OUTPUT;i++)
    95		  ho_w[j][i]+=ETA*o_del[i]*h_lay[j];
    96	      for(j=0;j<=INPUT;j++)
    97		for(i=0;i<HIDDEN;i++)
    98		  ih_w[j][i]+=ETA*h_del[i]*i_lay[ctg][j];
    99	    }
   100	    fprintf(stderr,"iteration = %4d, error = %1.5f\n",ite,err);
   101	    if((err<MIN_ERR)||(ite==ITERATIONS)){
   102	      for(ctg=0;ctg<CTG;ctg++){
   103		fprintf(stderr,"ctg[%d] : ",ctg);
   104		for(i=0;i<INPUT;i++)
   105		  fprintf(stderr,"i[%d] = %1.1f  ",i,i_lay[ctg][i]);
   106		for(j=0;j<HIDDEN;j++){
   107		  for(i=0,sum=0.;i<=INPUT;i++)
   108		    sum+=i_lay[ctg][i]*ih_w[i][j];
   109		  h_lay[j]=sigmoid(sum);
   110		}
   111		for(j=0;j<OUTPUT;j++){
   112		  for(i=0,sum=0.;i<=HIDDEN;i++)
   113		    sum+=h_lay[i]*ho_w[i][j];
   114		  o_lay[j]=sigmoid(sum);
   115		  fprintf(stderr,"o[%d] = %1.5f, t{%d] = %1.1f\n",j,o_lay[j],j,teach[ctg][j]);
   116		}
   117	      }
   118	      fprintf(stderr,"iteration = %4d, error = %1.5f\n",ite,err);
   119	      break;
   120	    }
   121	  }
   122	}
   123	
   124	double sigmoid(s)
   125		double s;
   126	{
   127		double sm;
   128		
   129		sm=EPSILON*s;
   130		if(sm>SMAX)			return(MAX);
   131		else if(sm<SMIN)	return(MIN);
   132		else				return(1./(1.+exp(-sm)));
   133	}