/// <summary>
/// Collapses the specified full buffers (must not include partial buffer).
/// </summary>
/// <param name="buffers">the buffers to be collapsed (all of them must be full or partially full)</param>
/// <returns>a full buffer containing the collapsed values. The buffer has accumulated weight.</returns>
public DoubleBuffer Collapse(DoubleBuffer[] buffers)
{
//determine W
int W = 0; //sum of all weights
for (int i = 0; i < buffers.Length; i++)
{
W += buffers[i].Weight;
}
//determine outputTriggerPositions
int k = this.NumberOfElements;
long[] triggerPositions = new long[k];
for (int j = 0; j < k; j++)
{
triggerPositions[j] = this.NextTriggerPosition(j, W);
}
//do the main work: determine values at given positions in sorted sequence
double[] outputValues = this.GetValuesAtPositions(buffers, triggerPositions);
//mark all full buffers as empty, except the first, which will contain the output
for (int b = 1; b < buffers.Length; b++)
{
buffers[b].Clear();
}
DoubleBuffer outputBuffer = buffers[0];
outputBuffer.Values.Clear();
outputBuffer.Values.SetElements(outputValues);
outputBuffer.Weight = W;
return(outputBuffer);
}
protected void RemoveInfinitiesFrom(int infinities, DoubleBuffer buffer)
{
int plusInf = 0;
int minusInf = 0;
// count them (this is not very clever but it's safe)
Boolean even = true;
for (int i = 0; i < infinities; i++)
{
if (even)
{
plusInf++;
}
else
{
minusInf++;
}
even = !even;
}
buffer.Values.RemoveFromTo(buffer.Size - plusInf, buffer.Size - 1);
buffer.Values.RemoveFromTo(0, minusInf - 1);
//this.totalElementsFilled -= infinities;
}
/// <summary>
/// Determines all values of the specified buffers positioned at the specified triggerPositions within the sorted sequence and fills them into outputValues.
/// </summary>
/// <param name="buffers">the buffers to be searched (all must be full or partial) </param>
/// <param name="triggerPositions">the positions of elements within the sorted sequence to be retrieved</param>
/// <returns>outputValues a list filled with the values at triggerPositions</returns>
internal double[] GetValuesAtPositions(DoubleBuffer[] buffers, long[] triggerPositions)
{
//if (buffers.Length==0)
//{
// throw new ArgumentException("Oops! buffer.Length==0.");
//}
//System.out.println("triggers="+cern.it.util.Arrays.ToString(positions));
//new List<Double>(outputValues).FillFromToWith(0, outputValues.Length-1, 0.0f);
//delte the above line, it is only for testing
//cern.it.util.Log.println("\nEntering getValuesAtPositions...");
//cern.it.util.Log.println("hitPositions="+cern.it.util.Arrays.ToString(positions));
// sort buffers.
for (int i = buffers.Length; --i >= 0;)
{
buffers[i].Sort();
}
// collect some infos into fast cache; for tuning purposes only.
int[] bufferSizes = new int[buffers.Length];
double[][] bufferValues = new double[buffers.Length][];
int totalBuffersSize = 0;
for (int i = buffers.Length; --i >= 0;)
{
bufferSizes[i] = buffers[i].Size;
bufferValues[i] = buffers[i].Values.ToArray();
totalBuffersSize += bufferSizes[i];
//cern.it.util.Log.println("buffer["+i+"]="+buffers[i].Values);
}
// prepare merge of equi-distant elements within buffers into output values
// first collect some infos into fast cache; for tuning purposes only.
int buffersSize = buffers.Length;
int triggerPositionsLength = triggerPositions.Length;
// now prepare the important things.
int j = 0; //current position in collapsed values
int[] cursors = new int[buffers.Length]; //current position in each buffer; init with zeroes
long counter = 0; //current position in sorted sequence
long nextHit = triggerPositions[j]; //next position in sorted sequence to trigger output population
double[] outputValues = new double[triggerPositionsLength];
if (totalBuffersSize == 0)
{
// nothing to output, because no elements have been filled (we are empty).
// return meaningless values
for (int i = 0; i < triggerPositions.Length; i++)
{
outputValues[i] = Double.NaN;
}
return(outputValues);
}
// fill all output values with equi-distant elements.
while (j < triggerPositionsLength)
{
//System.out.println("\nj="+j);
//System.out.println("counter="+counter);
//System.out.println("nextHit="+nextHit);
// determine buffer with smallest value at cursor position.
double minValue = Double.PositiveInfinity;
int minBufferIndex = -1;
for (int b = buffersSize; --b >= 0;)
{
//DoubleBuffer buffer = buffers[b];
//if (cursors[b] < buffer.Length) {
if (cursors[b] < bufferSizes[b])
{
///double value = buffer.Values[cursors[b]];
double value = bufferValues[b][cursors[b]];
if (value <= minValue)
{
minValue = value;
minBufferIndex = b;
}
}
}
DoubleBuffer minBuffer = buffers[minBufferIndex];
// trigger copies into output sequence, if necessary.
counter += minBuffer.Weight;
while (counter > nextHit && j < triggerPositionsLength)
{
outputValues[j++] = minValue;
//System.out.println("adding to output="+minValue);
if (j < triggerPositionsLength)
{
nextHit = triggerPositions[j];
}
}
// that element has now been treated, move further.
cursors[minBufferIndex]++;
//System.out.println("cursors="+cern.it.util.Arrays.ToString(cursors));
} //end while (j<k)
//cern.it.util.Log.println("returning output="+cern.it.util.Arrays.ToString(outputValues));
return(outputValues);
}
