/// <summary>
/// Computes the error gradient w.r.t the inputs.
/// </summary>
/// <param name="colTop">top output Blob vector (Length 1), providing the error gradient
/// with respect to computed outputs.</param>
/// <param name="rgbPropagateDown">propagate down see Layer::Backward</param>
/// <param name="colBottom">bottom input Blob vector (Length 1)
/// </param>
protected override void backward(BlobCollection <T> colTop, List <bool> rgbPropagateDown, BlobCollection <T> colBottom)
{
if (!rgbPropagateDown[0])
{
return;
}
if (m_nPyramidHeight == 1)
{
m_rgPoolingLayers[0].Backward(colTop, rgbPropagateDown, colBottom);
return;
}
List <bool> rgbConcatPropagateDown = Utility.Create <bool>(m_nPyramidHeight, true);
m_concat_layer.Backward(colTop, rgbConcatPropagateDown, m_colBlobConcatBottomVec);
for (int i = 0; i < m_nPyramidHeight; i++)
{
m_rgFlattenLayers[i].Backward(m_rgFlattenLayerTopVecs[i], rgbPropagateDown, m_rgPoolingTopVecs[i]);
m_rgPoolingLayers[i].Backward(m_rgPoolingTopVecs[i], rgbPropagateDown, m_rgPoolingBottomVec[i]);
}
m_split_layer.Backward(m_colBlobSplitTopVec, rgbPropagateDown, colBottom);
}
private void WithinChannelBackward(BlobCollection <T> colTop, List <bool> rgbPropagateDown, BlobCollection <T> colBottom)
{
if (rgbPropagateDown[0])
{
List <bool> rgbProductPropagateDown = Utility.Create <bool>(2, true);
m_productLayer.Backward(colTop, rgbProductPropagateDown, m_colProductBottomVec);
m_powerLayer.Backward(m_colPowerTopVec, rgbPropagateDown, m_colPoolTopVec);
m_poolLayer.Backward(m_colPoolTopVec, rgbPropagateDown, m_colSquareTopVec);
m_squareLayer.Backward(m_colSquareTopVec, rgbPropagateDown, m_colSquareBottomVec);
m_splitLayer.Backward(m_colSplitTopVec, rgbPropagateDown, colBottom);
}
}
