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	30000
    13	
    14	#define ETA		1.20
    15	#define EPSILON	1.00
    16	#define WD		4.00
    17	#define MIN_ERR	0.000000001
    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	double	ih_lw[INPUT+1][HIDDEN],
    46			ho_lw[HIDDEN+1][OUTPUT];
    47	
    48	//extern double sigmoid();
    49	double sigmoid(double s);
    50	
    51	main(argc,argv)
    52		int	argc;
    53		char **argv;
    54	{
    55	  int	i,j,ite,ctg;
    56	  double err,sum;
    57	  srand((int)time((long *)0));
    58	  
    59	  /* ExOR Problem */
    60	  i_lay[0][0]=OFF; i_lay[0][1]=OFF; i_lay[0][2]=ON; teach[0][0]=OFF;
    61	  i_lay[1][0]=ON;  i_lay[1][1]=OFF; i_lay[1][2]=ON; teach[1][0]=ON;
    62	  i_lay[2][0]=OFF; i_lay[2][1]=ON;  i_lay[2][2]=ON; teach[2][0]=ON;
    63	  i_lay[3][0]=ON; i_lay[3][1]=ON;  i_lay[3][2]=ON; teach[3][0]=OFF;
    64	
    65	  h_lay[HIDDEN]=ON;
    66		
    67	  for(j=0;j<HIDDEN;j++)
    68	    for(i=0;i<=INPUT;i++)
    69	      ih_w[i][j]=WD*drand();
    70	  for(j=0;j<OUTPUT;j++)
    71	    for(i=0;i<=HIDDEN;i++)
    72	      ho_w[i][j]=WD*drand();
    73	
    74	  for(ite=0;ite<=ITERATIONS; ite++){
    75	    for(j=0;j<HIDDEN;j++)
    76	      for(i=0;i<=INPUT;i++)
    77		ih_lw[i][j]=0.;
    78	    for(j=0;j<OUTPUT;j++)
    79	      for(i=0;i<=HIDDEN;i++)
    80		ho_lw[i][j]=0.;
    81	    
    82	    for(ctg=0,err=0.;ctg<CTG;ctg++){
    83	      for(j=0;j<HIDDEN;j++){
    84		for(i=0,sum=0.;i<=INPUT;i++)
    85		  sum+=i_lay[ctg][i]*ih_w[i][j];
    86		h_lay[j]=sigmoid(sum);
    87	      }
    88	      for(j=0;j<OUTPUT;j++){
    89		for(i=0,sum=0.;i<=HIDDEN;i++)
    90		  sum+=h_lay[i]*ho_w[i][j];
    91		o_lay[j]=sigmoid(sum);
    92	      }
    93	      for(i=0;i<OUTPUT;i++){
    94		err+=sq(teach[ctg][i]-o_lay[i])/2./(double)CTG;
    95		o_del[i]=EPSILON*(teach[ctg][i]-o_lay[i])*o_lay[i]*(1.-o_lay[i]);
    96	      }
    97	      for(j=0;j<=HIDDEN;j++){
    98		h_del[j]=0.;
    99		for(i=0;i<OUTPUT;i++)
   100		  h_del[j]+=o_del[i]*ho_w[j][i];
   101		h_del[j]*=EPSILON*h_lay[j]*(1.-h_lay[j]);
   102	      }
   103	      
   104	      for(j=0;j<=HIDDEN;j++)
   105		for(i=0;i<OUTPUT;i++)
   106		  ho_lw[j][i]+=ETA*o_del[i]*h_lay[j];
   107	      for(j=0;j<=INPUT;j++)
   108		for(i=0;i<HIDDEN;i++)
   109		  ih_lw[j][i]+=ETA*h_del[i]*i_lay[ctg][j];
   110	    }
   111	    fprintf(stderr,"iteration = %4d, error = %1.5f\n",ite,err);
   112	    if((err<MIN_ERR)||(ite==ITERATIONS)){
   113	      for(ctg=0;ctg<CTG;ctg++){
   114		fprintf(stderr,"ctg[%d] : ",ctg);
   115		for(i=0;i<INPUT;i++)
   116		  fprintf(stderr,"i[%d] = %1.1f  ",i,i_lay[ctg][i]);
   117		for(j=0;j<HIDDEN;j++){
   118		  for(i=0,sum=0.;i<=INPUT;i++)
   119		    sum+=i_lay[ctg][i]*ih_w[i][j];
   120		  h_lay[j]=sigmoid(sum);
   121		}
   122		for(j=0;j<OUTPUT;j++){
   123		  for(i=0,sum=0.;i<=HIDDEN;i++)
   124		    sum+=h_lay[i]*ho_w[i][j];
   125		  o_lay[j]=sigmoid(sum);
   126		  fprintf(stderr,"o[%d] = %1.5f, t{%d] = %1.1f\n",j,o_lay[j],j,teach[ctg][j]);
   127		}
   128	      }
   129	      fprintf(stderr,"iteration = %4d, error = %1.5f\n",ite,err);
   130	      break;
   131	    }
   132	    for(j=0;j<=HIDDEN;j++)
   133	      for(i=0;i<OUTPUT;i++)
   134		ho_w[j][i]+=ho_lw[j][i];
   135	    for(j=0;j<=INPUT;j++)
   136	      for(i=0;i<HIDDEN;i++)
   137		ih_w[j][i]+=ih_lw[j][i];
   138	  }
   139	}
   140	
   141	double sigmoid(double s)
   142	{
   143	  double sm;
   144	  
   145	  sm=EPSILON*s;
   146	  if(sm>SMAX)			return(MAX);
   147	  else if(sm<SMIN)	return(MIN);
   148	  else				return(1./(1.+exp(-sm)));
   149	}