/**
* Update the boost factors for all columns. The boost factors are used to increase the overlap of
* inactive columns to improve their chances of becoming active. and hence encourage participation
* of more columns in the learning process. This is a line defined as: y = mx + b boost =
* (1-maxBoost)/minDuty * dutyCycle + maxFiringBoost. Intuitively this means that columns that
* have been active enough have a boost factor of 1, meaning their overlap is not boosted. Columns
* whose active duty cycle drops too much below that of their neighbors are boosted depending on
* how infrequently they have been active. The more infrequent, the more they are boosted. The
* exact boost factor is linearly interpolated between the points (dutyCycle:0,
* boost:maxFiringBoost) and (dutyCycle:minDuty, boost:1.0).
*
* <p>boostFactor ^ maxBoost _ | |\ | \ 1 _ | \ _ _ _ _ _ _ _ | +-------------------->
* activeDutyCycle | minActiveDutyCycle
*/
public void updateBoostFactors(Connections c) {
double[] activeDutyCycles = c.getActiveDutyCycles();
double[] minActiveDutyCycles = c.getMinActiveDutyCycles();
// Indexes of values > 0
int[] mask = ArrayUtils.where(minActiveDutyCycles, ArrayUtils.GREATER_THAN_0);
double[] boostInterim;
if (mask.length < 1) {
boostInterim = c.getBoostFactors();
} else {
double[] numerator = new double[c.getNumColumns()];
Arrays.fill(numerator, 1 - c.getMaxBoost());
boostInterim = ArrayUtils.divide(numerator, minActiveDutyCycles, 0, 0);
boostInterim = ArrayUtils.multiply(boostInterim, activeDutyCycles, 0, 0);
boostInterim = ArrayUtils.d_add(boostInterim, c.getMaxBoost());
}
ArrayUtils.setIndexesTo(
boostInterim,
ArrayUtils.where(
activeDutyCycles,
new Condition.Adapter<Object>() {
int i = 0;
@Override
public boolean eval(double d) {
return d > minActiveDutyCycles[i++];
}
}),
1.0d);
c.setBoostFactors(boostInterim);
}
/**
* Updates the minimum duty cycles in a global fashion. Sets the minimum duty cycles for the
* overlap and activation of all columns to be a percent of the maximum in the region, specified
* by {@link Connections#getMinOverlapDutyCycles()} and minPctActiveDutyCycle respectively.
* Functionality it is equivalent to {@link #updateMinDutyCyclesLocal(Connections)}, but this
* function exploits the globalness of the computation to perform it in a straightforward, and
* more efficient manner.
*
* @param c
*/
public void updateMinDutyCyclesGlobal(Connections c) {
Arrays.fill(
c.getMinOverlapDutyCycles(),
c.getMinPctOverlapDutyCycles() * ArrayUtils.max(c.getOverlapDutyCycles()));
Arrays.fill(
c.getMinActiveDutyCycles(),
c.getMinPctActiveDutyCycles() * ArrayUtils.max(c.getActiveDutyCycles()));
}
/**
* Updates the minimum duty cycles. The minimum duty cycles are determined locally. Each column's
* minimum duty cycles are set to be a percent of the maximum duty cycles in the column's
* neighborhood. Unlike {@link #updateMinDutyCyclesGlobal(Connections)}, here the values can be
* quite different for different columns.
*
* @param c
*/
public void updateMinDutyCyclesLocal(Connections c) {
int len = c.getNumColumns();
for (int i = 0; i < len; i++) {
int[] maskNeighbors =
getNeighborsND(c, i, c.getMemory(), c.getInhibitionRadius(), true).toArray();
c.getMinOverlapDutyCycles()[i] =
ArrayUtils.max(ArrayUtils.sub(c.getOverlapDutyCycles(), maskNeighbors))
* c.getMinPctOverlapDutyCycles();
c.getMinActiveDutyCycles()[i] =
ArrayUtils.max(ArrayUtils.sub(c.getActiveDutyCycles(), maskNeighbors))
* c.getMinPctActiveDutyCycles();
}
}