Nasal-Interpreter/test/bp.nas

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rand(time(0));
var new_neuron=func(){
return {
in:0,
out:0,
w:[],
bia:0,
diff:0
};
}
var tanh=func(x){
var (a,b)=(math.exp(x),math.exp(-x));
return (a-b)/(a+b);
}
var difftanh=func(x){
x=tanh(x);
return 1-x*x;
}
var sigmoid=func(x){
return 1/(1+math.exp(-x));
}
var diffsigmoid=func(x){
x=sigmoid(x);
return x*(1-x);
}
var (inum,hnum,onum)=(2,4,1);
var training_set=[[0,0],[0,1],[1,0],[1,1]];
var expect=[0,1,1,0];
var hidden=[];
for(var i=0;i<hnum;i+=1){
append(hidden,new_neuron());
for(var j=0;j<inum;j+=1)
append(hidden[i].w,rand()>0.5?-2*rand():2*rand());
hidden[i].bia=rand()>0.5?-5*rand():5*rand();
}
var output=[];
for(var i=0;i<onum;i+=1){
append(output,new_neuron());
for(var j=0;j<hnum;j+=1)
append(output[i].w,rand()>0.5?-2*rand():2*rand());
output[i].bia=rand()>0.5?-5*rand():5*rand();
}
var forward=func(x){
var input=training_set[x];
for(var i=0;i<hnum;i+=1){
hidden[i].in=hidden[i].bia;
for(var j=0;j<inum;j+=1)
hidden[i].in+=hidden[i].w[j]*input[j];
hidden[i].out=tanh(hidden[i].in);
}
for(var i=0;i<onum;i+=1){
output[i].in=output[i].bia;
for(var j=0;j<hnum;j+=1)
output[i].in+=output[i].w[j]*hidden[j].out;
output[i].out=sigmoid(output[i].in);
}
return;
}
var run=func(vec){
var input=vec;
for(var i=0;i<hnum;i+=1){
hidden[i].in=hidden[i].bia;
for(var j=0;j<inum;j+=1)
hidden[i].in+=hidden[i].w[j]*input[j];
hidden[i].out=tanh(hidden[i].in);
}
for(var i=0;i<onum;i+=1){
output[i].in=output[i].bia;
for(var j=0;j<hnum;j+=1)
output[i].in+=output[i].w[j]*hidden[j].out;
output[i].out=sigmoid(output[i].in);
}
return;
}
var get_error=func(x){
return 0.5*(expect[x]-output[0].out)*(expect[x]-output[0].out);
}
var backward=func(x){
var input=training_set[x];
output[0].diff=(expect[x]-output[0].out)*diffsigmoid(output[0].in);
for(var i=0;i<hnum;i+=1){
hidden[i].diff=0;
for(var j=0;j<onum;j+=1)
hidden[i].diff+=output[j].w[i]*output[j].diff;
hidden[i].diff*=difftanh(hidden[i].in);
}
for(var i=0;i<hnum;i+=1){
hidden[i].bia+=hidden[i].diff;
for(var j=0;j<inum;j+=1)
hidden[i].w[j]+=hidden[i].diff*input[j];
}
for(var i=0;i<onum;i+=1){
output[i].bia+=output[i].diff;
for(var j=0;j<hnum;j+=1)
output[i].w[j]+=output[i].diff*hidden[j].out;
}
return;
}
var (cnt,error)=(0,100);
while(error>0.0005){
error=0;
for(var i=0;i<4;i+=1){
forward(i);
error+=get_error(i);
backward(i);
}
cnt+=1;
}
print('finished after ',cnt,' epoch.\n');
foreach(var v;training_set){
run(v);
print(v,': ',output[0].out,'\n');
}