/// 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();
}
