/*
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
updateMinDutyCyclesGlobal, here the values can be quite different for
different columns.
*/
func (sp *SpatialPooler) updateMinDutyCyclesLocal(getNeighborsND getNeighborsNDFunc) {
for i := 0; i < sp.numColumns; i++ {
maskNeighbors := getNeighborsND(i, sp.ColumnDimensions, sp.inhibitionRadius, false)
maskNeighbors = append(maskNeighbors, i)
maxOverlap := utils.MaxSliceFloat64(utils.SubsetSliceFloat64(sp.overlapDutyCycles, maskNeighbors))
sp.minOverlapDutyCycles[i] = maxOverlap * sp.MinPctOverlapDutyCycles
maxActive := utils.MaxSliceFloat64(utils.SubsetSliceFloat64(sp.activeDutyCycles, maskNeighbors))
sp.minActiveDutyCycles[i] = maxActive * sp.MinPctActiveDutyCycles
}
}
func (sp *SpatialPooler) inhibitColumnsLocal(overlaps []float64, density float64) []int {
var activeColumns []int
addToWinners := utils.MaxSliceFloat64(overlaps) / 1000.0
for i := 0; i < sp.numColumns; i++ {
mask := sp.getNeighborsND(i, sp.ColumnDimensions, sp.inhibitionRadius, false)
ovSlice := make([]float64, len(mask))
for idx, val := range mask {
ovSlice[idx] = overlaps[val]
}
numActive := int(0.5 + density*float64(len(mask)+1))
numBigger := 0
for _, ov := range ovSlice {
if ov > overlaps[i] {
numBigger++
}
}
if numBigger < numActive {
activeColumns = append(activeColumns, i)
overlaps[i] += addToWinners
}
}
return activeColumns
}
/*
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 minPctOverlapDutyCycle and
minPctActiveDutyCycle respectively. Functionaly it is equivalent to
updateMinDutyCyclesLocal, but this function exploits the globalilty of the
compuation to perform it in a straightforward, and more efficient manner.
*/
func (sp *SpatialPooler) updateMinDutyCyclesGlobal() {
minOverlap := sp.MinPctOverlapDutyCycles * utils.MaxSliceFloat64(sp.overlapDutyCycles)
utils.FillSliceFloat64(sp.minOverlapDutyCycles, minOverlap)
minActive := sp.MinPctActiveDutyCycles * utils.MaxSliceFloat64(sp.activeDutyCycles)
utils.FillSliceFloat64(sp.minActiveDutyCycles, minActive)
}