/**
* This method updates the permanence matrix with a column's new permanence values. The column is
* identified by its index, which reflects the row in the matrix, and the permanence is given in
* 'sparse' form, (i.e. an array whose members are associated with specific indexes). It is in
* charge of implementing 'clipping' - ensuring that the permanence values are always between 0
* and 1 - and 'trimming' - enforcing sparseness by zeroing out all permanence values below
* 'synPermTrimThreshold'. Every method wishing to modify the permanence matrix should do so
* through this method.
*
* @param c the {@link Connections} which is the memory model.
* @param perm An array of permanence values for a column. The array is "sparse", i.e. it contains
* an entry for each input bit, even if the permanence value is 0.
* @param column The column in the permanence, potential and connectivity matrices
* @param raisePerm a boolean value indicating whether the permanence values
*/
public void updatePermanencesForColumnSparse(
Connections c, double[] perm, Column column, int[] maskPotential, boolean raisePerm) {
if (raisePerm) {
raisePermanenceToThresholdSparse(c, perm);
}
ArrayUtils.lessThanOrEqualXThanSetToY(perm, c.getSynPermTrimThreshold(), 0);
ArrayUtils.clip(perm, c.getSynPermMin(), c.getSynPermMax());
column.setProximalPermanencesSparse(c, perm, maskPotential);
}
/**
* Initializes the permanences of a column. The method returns a 1-D array the size of the input,
* where each entry in the array represents the initial permanence value between the input bit at
* the particular index in the array, and the column represented by the 'index' parameter.
*
* @param c the {@link Connections} which is the memory model
* @param potentialPool An array specifying the potential pool of the column. Permanence values
* will only be generated for input bits corresponding to indices for which the mask value is
* 1. WARNING: potentialPool is sparse, not an array of "1's"
* @param index the index of the column being initialized
* @param connectedPct A value between 0 or 1 specifying the percent of the input bits that will
* start off in a connected state.
* @return
*/
public double[] initPermanence(
Connections c, int[] potentialPool, int index, double connectedPct) {
double[] perm = new double[c.getNumInputs()];
for (int idx : potentialPool) {
if (c.random.nextDouble() <= connectedPct) {
perm[idx] = initPermConnected(c);
} else {
perm[idx] = initPermNonConnected(c);
}
perm[idx] = perm[idx] < c.getSynPermTrimThreshold() ? 0 : perm[idx];
}
c.getColumn(index).setProximalPermanences(c, perm);
return perm;
}
