/// <summary>
/// Given the top Blob error gradients, compute the bottom Blob error gradients.
/// </summary>
/// <remarks>
/// The Backward function calls the overriden backward function implemented by each specific Layer derivative,
/// to compute the bottom (input) Blob diffs given the top (output) Blob diffs.
/// </remarks>
/// <param name="colTop">Specifies a collection of top (output) Blobs, whos diff fields store the gradient of the
/// error with respect to themselves.</param>
/// <param name="rgbPropagateDown">Specifies a List with equal length to the bottom, with each element
/// indicating whether or not to propagate the error gradients down to the bottom Blob at the corresponding
/// index.</param>
/// <param name="colBottom">Specifies a collection of bottom (input) Blobs, whos diff fields are filled with
/// the gradient of the error with respect to themselves after the Backward function is run.</param>
public void Backward(BlobCollection <T> colTop, List <bool> rgbPropagateDown, BlobCollection <T> colBottom)
{
try
{
m_swTiming.Restart();
backward(colTop, rgbPropagateDown, colBottom);
m_swTiming.Stop();
m_dfBackwardTiming = m_swTiming.Elapsed.TotalMilliseconds;
m_dfBackwardAverageTiming = getAveTiming(m_dfAverageInterval, m_dfBackwardTiming, m_dfBackwardAverageTiming);
if (OnDebug != null)
{
GetWorkBlobArgs <T> args = new GetWorkBlobArgs <T>();
OnDebug(this, args);
foreach (Blob <T> b in colBottom)
{
Tuple <double, double, double, double> mm_data = b.minmax_data(args.Blob, true);
Tuple <double, double, double, double> mm_diff = b.minmax_diff(args.Blob, true);
if (mm_data.Item3 > 0 || mm_data.Item4 > 0)
{
throw new Exception("NAN or INF detected in the BOTTOM '" + b.Name + "' Data for layer '" + m_param.name + "' on the backward pass.");
}
if (mm_diff.Item3 > 0 || mm_diff.Item4 > 0)
{
throw new Exception("NAN or INF detected in the BOTTOM '" + b.Name + "' Diff for layer '" + m_param.name + "' on the backward pass.");
}
}
}
}
catch (Exception excpt)
{
if (m_param != null)
{
throw new Exception("Layer: '" + m_param.name + "' (" + m_param.type.ToString() + ") Error: " + excpt.Message, excpt);
}
else
{
throw excpt;
}
}
}
/// <summary>
/// Given the bottom (input) Blobs, this function computes the top (output) Blobs and the loss.
/// </summary>
/// <remarks>
/// The Forward function calls the overriden forward function implemented by each specific Layer derivative
/// to compute the top (output) Blob's values given the bottom (input) Blobs. If the layer has any non-zero
/// <code>loss_weights</code> this function then computes and returns the loss.
/// </remarks>
/// <param name="colBottom">Specifies the collection of bottom (input) Blobs, whos data fields
/// store the input data for this layers' outputs.</param>
/// <param name="colTop">Specifies the collection of preshaped top (output) Blobs, whos data fields
/// will store this layers' outputs.</param>
/// <returns>Returns the total loss from the Layer.</returns>
public double Forward(BlobCollection <T> colBottom, BlobCollection <T> colTop)
{
try
{
m_swTiming.Restart();
double dfLoss = 0;
Reshape(colBottom, colTop);
forward(colBottom, colTop);
for (int i = 0; i < colTop.Count; i++)
{
if (loss(i) == 0)
{
continue;
}
int nCount = colTop[i].count();
long hData = colTop[i].gpu_data;
long hDiff = colTop[i].gpu_diff;
double dfBlobLoss = m_cuda.dot_double(nCount, hData, hDiff);
dfLoss += dfBlobLoss;
}
m_swTiming.Stop();
m_dfForwardTiming = m_swTiming.Elapsed.TotalMilliseconds;
m_dfForwardAverageTiming = getAveTiming(m_dfAverageInterval, m_dfForwardTiming, m_dfForwardAverageTiming);
if (OnDebug != null)
{
GetWorkBlobArgs <T> args = new GetWorkBlobArgs <T>();
OnDebug(this, args);
foreach (Blob <T> b in colTop)
{
Tuple <double, double, double, double> mm_data = b.minmax_data(args.Blob, true);
Tuple <double, double, double, double> mm_diff = b.minmax_diff(args.Blob, true);
if (mm_data.Item3 > 0 || mm_data.Item4 > 0)
{
throw new Exception("NAN or INF detected in the TOP '" + b.Name + "' Data for layer '" + m_param.name + "' on the forward pass.");
}
if (mm_diff.Item3 > 0 || mm_diff.Item4 > 0)
{
throw new Exception("NAN or INF detected in TOP '" + b.Name + "' Diff for layer '" + m_param.name + "' on the forward pass.");
}
}
}
return(dfLoss);
}
catch (Exception excpt)
{
if (m_param != null)
{
throw new Exception("Layer: '" + m_param.name + "' (" + m_param.type.ToString() + ") Error: " + excpt.Message, excpt);
}
else
{
throw excpt;
}
}
}
