/// update - Recompute Value from Bias and Links. Return true when node
/// preference changes.
bool update(const Node nodes[]) {
// Compute the weighted sum of inputs.
BlockFrequency SumN = BiasN;
BlockFrequency SumP = BiasP;
for (LinkVector::iterator I = Links.begin(), E = Links.end(); I != E; ++I) {
if (nodes[I->second].Value == -1)
SumN += I->first;
else if (nodes[I->second].Value == 1)
SumP += I->first;
}
// Each weighted sum is going to be less than the total frequency of the
// bundle. Ideally, we should simply set Value = sign(SumP - SumN), but we
// will add a dead zone around 0 for two reasons:
//
// 1. It avoids arbitrary bias when all links are 0 as is possible during
// initial iterations.
// 2. It helps tame rounding errors when the links nominally sum to 0.
//
bool Before = preferReg();
if (SumN >= SumP + Threshold)
Value = -1;
else if (SumP >= SumN + Threshold)
Value = 1;
else
Value = 0;
return Before != preferReg();
}
/// addLink - Add a link to bundle b with weight w.
/// out=0 for an ingoing link, and 1 for an outgoing link.
void addLink(unsigned b, float w, bool out) {
// Normalize w relative to all connected blocks from that direction.
w /= Frequency[out];
// There can be multiple links to the same bundle, add them up.
for (LinkVector::iterator I = Links.begin(), E = Links.end(); I != E; ++I)
if (I->second == b) {
I->first += w;
return;
}
// This must be the first link to b.
Links.push_back(std::make_pair(w, b));
}
/// addLink - Add a link to bundle b with weight w.
void addLink(unsigned b, BlockFrequency w) {
// Update cached sum.
SumLinkWeights += w;
// There can be multiple links to the same bundle, add them up.
for (LinkVector::iterator I = Links.begin(), E = Links.end(); I != E; ++I)
if (I->second == b) {
I->first += w;
return;
}
// This must be the first link to b.
Links.push_back(std::make_pair(w, b));
}
/// update - Recompute Value from Bias and Links. Return true when node
/// preference changes.
bool update(const Node nodes[]) {
// Compute the weighted sum of inputs.
float Sum = Bias;
for (LinkVector::iterator I = Links.begin(), E = Links.end(); I != E; ++I)
Sum += I->first * nodes[I->second].Value;
// The weighted sum is going to be in the range [-2;2]. Ideally, we should
// simply set Value = sign(Sum), but we will add a dead zone around 0 for
// two reasons:
// 1. It avoids arbitrary bias when all links are 0 as is possible during
// initial iterations.
// 2. It helps tame rounding errors when the links nominally sum to 0.
const float Thres = 1e-4f;
bool Before = preferReg();
if (Sum < -Thres)
Value = -1;
else if (Sum > Thres)
Value = 1;
else
Value = 0;
return Before != preferReg();
}
