//IMPLEMENTATION OF SHIFT - page 9
internal ShiftedAddressing(Unit shift, GatedAddressing gatedAddressing)
{
_shift = shift;
GatedAddressing = gatedAddressing;
_gatedVector = GatedAddressing.GatedVector;
_cellCount = _gatedVector.Length;
ShiftedVector = UnitFactory.GetVector(_cellCount);
double cellCountDbl = _cellCount;
//Max shift is from range -1 to 1
_shiftWeight = Sigmoid.GetValue(_shift.Value);
double maxShift = ((2 * _shiftWeight) - 1);
double convolutionDbl = (maxShift + cellCountDbl) % cellCountDbl;
_simj = 1 - (convolutionDbl - Math.Floor(convolutionDbl));
_oneMinusSimj = (1 - _simj);
_convolution = (int)convolutionDbl;
for (int i = 0; i < _cellCount; i++)
{
int imj = (i + _convolution) % _cellCount;
Unit vectorItem = ShiftedVector[i];
vectorItem.Value = (_gatedVector[imj].Value * _simj) +
(_gatedVector[(imj + 1) % _cellCount].Value * _oneMinusSimj);
if (vectorItem.Value < 0 || double.IsNaN(vectorItem.Value))
{
throw new Exception("Error - weight should not be smaller than zero or nan");
}
}
}
//IMPLEMENTATION OF SHIFT - page 9
internal ShiftedAddressing(Unit shift, GatedAddressing gatedAddressing)
{
_shift = shift;
GatedAddressing = gatedAddressing;
_gatedVector = GatedAddressing.GatedVector;
_cellCount = _gatedVector.Length;
ShiftedVector = UnitFactory.GetVector(_cellCount);
double cellCountDbl = _cellCount;
//Max shift is from range -1 to 1
_shiftWeight = Sigmoid.GetValue(_shift.Value);
double maxShift = ((2 * _shiftWeight) - 1);
double convolutionDbl = (maxShift + cellCountDbl) % cellCountDbl;
_simj = 1 - (convolutionDbl - Math.Floor(convolutionDbl));
_oneMinusSimj = (1 - _simj);
_convolution = (int)convolutionDbl;
for (int i = 0; i < _cellCount; i++)
{
int imj = (i + _convolution) % _cellCount;
Unit vectorItem = ShiftedVector[i];
vectorItem.Value = (_gatedVector[imj].Value * _simj) +
(_gatedVector[(imj + 1) % _cellCount].Value * _oneMinusSimj);
if (vectorItem.Value < 0 || double.IsNaN(vectorItem.Value))
{
throw new Exception("Error - weight should not be smaller than zero or nan");
}
}
}
internal MemoryState Process(Head[] heads)
{
int headCount = heads.Length;
int memoryColumnsN = _memory.CellCountN;
ReadData[] newReadDatas = new ReadData[headCount];
HeadSetting[] newHeadSettings = new HeadSetting[headCount];
for (int i = 0; i < headCount; i++)
{
Head head = heads[i];
BetaSimilarity[] similarities = new BetaSimilarity[_memory.CellCountN];
for (int j = 0; j < memoryColumnsN; j++)
{
Unit[] memoryColumn = _memory.Data[j];
SimilarityMeasure similarity = new SimilarityMeasure(new CosineSimilarityFunction(), head.KeyVector, memoryColumn);
similarities[j] = new BetaSimilarity(head.Beta, similarity);
}
ContentAddressing ca = new ContentAddressing(similarities);
GatedAddressing ga = new GatedAddressing(head.Gate, ca, _headSettings[i]);
ShiftedAddressing sa = new ShiftedAddressing(head.Shift, ga);
newHeadSettings[i] = new HeadSetting(head.Gamma, sa);
newReadDatas[i] = new ReadData(newHeadSettings[i], _memory);
}
NTMMemory newMemory = new NTMMemory(newHeadSettings, heads, _memory);
return new MemoryState(newMemory, newHeadSettings, newReadDatas);
}