public IMatrix ReverseMaxPool(IMatrix error, int size, int filterSize, int filterDepth, IReadOnlyList <int[]> indexList)
{
var filterIndex = 0;
var filters = error.ConvertInPlaceToVector().Split(filterDepth);
var sparseDictionary = Enumerable.Range(0, filterDepth).Select(i => new Dictionary <Tuple <int, int>, float>()).ToList();
foreach (var item in filters)
{
var itemIndex = 0;
int xOffset = 0, yOffset = 0;
foreach (var value in item.AsIndexable().Values)
{
var maxIndex = indexList[itemIndex][filterIndex];
var yIndex = maxIndex / filterSize;
var xIndex = maxIndex % filterSize;
sparseDictionary[filterIndex].Add(Tuple.Create(xOffset + xIndex, yOffset + yIndex), value);
xOffset += filterSize;
if (xOffset >= size)
{
yOffset += filterSize;
xOffset = 0;
}
++itemIndex;
}
++filterIndex;
}
var ret = DenseMatrix.Create(size * size, filterDepth, (i, j) => {
var y = i / size;
var x = i % size;
float val;
if (sparseDictionary[j].TryGetValue(Tuple.Create(x, y), out val))
{
return(val);
}
return(0f);
});
return(new CpuMatrix(ret));
}
