This program is copyright © 1996 by the author. It is made available as is, and no warranty - about the program, its performance, or its conformity to any specification - is given or implied. It may be used, modified, and distributed freely for private and commercial purposes, as long as the original author is credited as part of the final work.
/******************************************************************************
==============
Network: Hopfield Model
==============
Application: Autoassociative Memory
Associative Recall of Images and Pattern Completion
Author: Karsten Kutza
Date: 30.1.96
Reference: J.J. Hopfield
Neural Networks and Physical Systems
with Emergent Collective Computational Abilities
Proceedings of the National Academy of Sciences, 79,
pp. 2554-2558, 1982
******************************************************************************/
/******************************************************************************
D E C L A R A T I O N S
******************************************************************************/
#include <stdlib.h>
#include <stdio.h>
typedef int BOOL;
typedef char CHAR;
typedef int INT;
#define FALSE 0
#define TRUE 1
#define NOT !
#define AND &&
#define OR ||
#define LO -1
#define HI +1
#define BINARY(x) ((x)==LO ? FALSE : TRUE)
#define BIPOLAR(x) ((x)==FALSE ? LO : HI)
typedef struct { /* A NET: */
INT Units; /* - number of units in this net */
INT* Output; /* - output of ith unit */
INT* Threshold; /* - threshold of ith unit */
INT** Weight; /* - connection weights to ith unit */
} NET;
/******************************************************************************
R A N D O M S D R A W N F R O M D I S T R I B U T I O N S
******************************************************************************/
void InitializeRandoms()
{
srand(4711);
}
INT RandomEqualINT(INT Low, INT High)
{
return rand() % (High-Low+1) + Low;
}
/******************************************************************************
A P P L I C A T I O N - S P E C I F I C C O D E
******************************************************************************/
#define NUM_DATA 5
#define X 10
#define Y 10
#define N (X * Y)
CHAR Pattern[NUM_DATA][Y][X] = { { "O O O O O ",
" O O O O O",
"O O O O O ",
" O O O O O",
"O O O O O ",
" O O O O O",
"O O O O O ",
" O O O O O",
"O O O O O ",
" O O O O O" },
{ "OO OO OO",
"OO OO OO",
" OO OO ",
" OO OO ",
"OO OO OO",
"OO OO OO",
" OO OO ",
" OO OO ",
"OO OO OO",
"OO OO OO" },
{ "OOOOO ",
"OOOOO ",
"OOOOO ",
"OOOOO ",
"OOOOO ",
" OOOOO",
" OOOOO",
" OOOOO",
" OOOOO",
" OOOOO" },
{ "O O O O",
" O O O ",
" O O O ",
"O O O O",
" O O O ",
" O O O ",
"O O O O",
" O O O ",
" O O O ",
"O O O O" },
{ "OOOOOOOOOO",
"O O",
"O OOOOOO O",
"O O O O",
"O O OO O O",
"O O OO O O",
"O O O O",
"O OOOOOO O",
"O O",
"OOOOOOOOOO" } };
CHAR Pattern_[NUM_DATA][Y][X] = { { " ",
" ",
" ",
" ",
" ",
" O O O O O",
"O O O O O ",
" O O O O O",
"O O O O O ",
" O O O O O" },
{ "OOO O O",
" O OOO OO",
" O O OO O",
" OOO O ",
"OO O OOO",
" O OOO O",
"O OO O O",
" O OOO ",
"OO OOO O ",
" O O OOO" },
{ "OOOOO ",
"O O OOO ",
"O O OOO ",
"O O OOO ",
"OOOOO ",
" OOOOO",
" OOO O O",
" OOO O O",
" OOO O O",
" OOOOO" },
{ "O OOOO O",
"OO OOOO ",
"OOO OOOO ",
"OOOO OOOO",
" OOOO OOO",
" OOOO OO",
"O OOOO O",
"OO OOOO ",
"OOO OOOO ",
"OOOO OOOO" },
{ "OOOOOOOOOO",
"O O",
"O O",
"O O",
"O OO O",
"O OO O",
"O O",
"O O",
"O O",
"OOOOOOOOOO" } };
INT Input [NUM_DATA][N];
INT Input_[NUM_DATA][N];
FILE* f;
void InitializeApplication(NET* Net)
{
INT n,i,j;
for (n=0; n<NUM_DATA; n++) {
for (i=0; i<Y; i++) {
for (j=0; j<X; j++) {
Input [n][i*X+j] = BIPOLAR(Pattern [n][i][j] == 'O');
Input_[n][i*X+j] = BIPOLAR(Pattern_[n][i][j] == 'O');
}
}
}
f = fopen("HOPFIELD.txt", "w");
}
void WriteNet(NET* Net)
{
INT i,j;
for (i=0; i<Y; i++) {
for (j=0; j<X; j++) {
fprintf(f, "%c", BINARY(Net->Output[i*X+j]) ? 'O' : ' ');
}
fprintf(f, "\n");
}
fprintf(f, "\n");
}
void FinalizeApplication(NET* Net)
{
fclose(f);
}
/******************************************************************************
I N I T I A L I Z A T I O N
******************************************************************************/
void GenerateNetwork(NET* Net)
{
INT i;
Net->Units = N;
Net->Output = (INT*) calloc(N, sizeof(INT));
Net->Threshold = (INT*) calloc(N, sizeof(INT));
Net->Weight = (INT**) calloc(N, sizeof(INT*));
for (i=0; i<N; i++) {
Net->Threshold[i] = 0;
Net->Weight[i] = (INT*) calloc(N, sizeof(INT));
}
}
void CalculateWeights(NET* Net)
{
INT i,j,n;
INT Weight;
for (i=0; i<Net->Units; i++) {
for (j=0; j<Net->Units; j++) {
Weight = 0;
if (i!=j) {
for (n=0; n<NUM_DATA; n++) {
Weight += Input[n][i] * Input[n][j];
}
}
Net->Weight[i][j] = Weight;
}
}
}
void SetInput(NET* Net, INT* Input)
{
INT i;
for (i=0; i<Net->Units; i++) {
Net->Output[i] = Input[i];
}
WriteNet(Net);
}
void GetOutput(NET* Net, INT* Output)
{
INT i;
for (i=0; i<Net->Units; i++) {
Output[i] = Net->Output[i];
}
WriteNet(Net);
}
/******************************************************************************
P R O P A G A T I N G S I G N A L S
******************************************************************************/
BOOL PropagateUnit(NET* Net, INT i)
{
INT j;
INT Sum, Out;
BOOL Changed;
Changed = FALSE;
Sum = 0;
for (j=0; j<Net->Units; j++) {
Sum += Net->Weight[i][j] * Net->Output[j];
}
if (Sum != Net->Threshold[i]) {
if (Sum < Net->Threshold[i]) Out = LO;
if (Sum > Net->Threshold[i]) Out = HI;
if (Out != Net->Output[i]) {
Changed = TRUE;
Net->Output[i] = Out;
}
}
return Changed;
}
void PropagateNet(NET* Net)
{
INT Iteration, IterationOfLastChange;
Iteration = 0;
IterationOfLastChange = 0;
do {
Iteration++;
if (PropagateUnit(Net, RandomEqualINT(0, Net->Units-1)))
IterationOfLastChange = Iteration;
} while (Iteration-IterationOfLastChange < 10*Net->Units);
}
/******************************************************************************
S I M U L A T I N G T H E N E T
******************************************************************************/
void SimulateNet(NET* Net, INT* Input)
{
INT Output[N];
SetInput(Net, Input);
PropagateNet(Net);
GetOutput(Net, Output);
}
/******************************************************************************
M A I N
******************************************************************************/
void main()
{
NET Net;
INT n;
InitializeRandoms();
GenerateNetwork(&Net);
InitializeApplication(&Net);
CalculateWeights(&Net);
for (n=0; n<NUM_DATA; n++) {
SimulateNet(&Net, Input[n]);
}
for (n=0; n<NUM_DATA; n++) {
SimulateNet(&Net, Input_[n]);
}
FinalizeApplication(&Net);
}
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O -> O O O O O
OO OO OO OO OO OO
OO OO OO OO OO OO
OO OO OO OO
OO OO OO OO
OO OO OO OO OO OO
OO OO OO OO OO OO
OO OO OO OO
OO OO OO OO
OO OO OO OO OO OO
OO OO OO -> OO OO OO
OOOOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOOOO -> OOOOO
O O O O O O O O
O O O O O O
O O O O O O
O O O O O O O O
O O O O O O
O O O O O O
O O O O O O O O
O O O O O O
O O O O O O
O O O O -> O O O O
OOOOOOOOOO OOOOOOOOOO
O O O O
O OOOOOO O O OOOOOO O
O O O O O O O O
O O OO O O O O OO O O
O O OO O O O O OO O O
O O O O O O O O
O OOOOOO O O OOOOOO O
O O O O
OOOOOOOOOO -> OOOOOOOOOO
O O O O O
O O O O O
O O O O O
O O O O O
O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O
O O O O O -> O O O O O
OOO O O OO OO OO
O OOO OO OO OO OO
O O OO O OO OO
OOO O OO OO
OO O OOO OO OO OO
O OOO O OO OO OO
O OO O O OO OO
O OOO OO OO
OO OOO O OO OO OO
O O OOO -> OO OO OO
OOOOO OOOOO
O O OOO OOOOO
O O OOO OOOOO
O O OOO OOOOO
OOOOO OOOOO
OOOOO OOOOO
OOO O O OOOOO
OOO O O OOOOO
OOO O O OOOOO
OOOOO -> OOOOO
O OOOO O O O O O
OO OOOO O O O
OOO OOOO O O O
OOOO OOOO O O O O
OOOO OOO O O O
OOOO OO O O O
O OOOO O O O O O
OO OOOO O O O
OOO OOOO O O O
OOOO OOOO -> O O O O
OOOOOOOOOO OOOOOOOOOO
O O O O
O O O OOOOOO O
O O O O O O
O OO O O O OO O O
O OO O O O OO O O
O O O O O O
O O O OOOOOO O
O O O O
OOOOOOOOOO -> OOOOOOOOOO