static uint[][] HistogramByteComponentsParInner(uint[] inArray, Int32 l, Int32 r, int parallelThreshold = 16 * 1024)
{
const int numberOfBins = 256;
const int numberOfDigits = sizeof(uint);
uint[][] countLeft = null;
uint[][] countRight = null;
if (l > r) // zero elements to compare
{
countLeft = new uint[numberOfDigits][];
for (int i = 0; i < numberOfDigits; i++)
{
countLeft[i] = new uint[numberOfBins];
}
return(countLeft);
}
if ((r - l + 1) <= parallelThreshold)
{
countLeft = new uint[numberOfDigits][];
for (int i = 0; i < numberOfDigits; i++)
{
countLeft[i] = new uint[numberOfBins];
}
uint[] countLeft0 = countLeft[0];
uint[] countLeft1 = countLeft[1];
uint[] countLeft2 = countLeft[2];
uint[] countLeft3 = countLeft[3];
var union = new Algorithm.UInt32ByteUnion();
for (int current = l; current <= r; current++) // Scan the array and count the number of times each digit value appears - i.e. size of each bin
{
union.integer = inArray[current];
countLeft0[union.byte0]++;
countLeft1[union.byte1]++;
countLeft2[union.byte2]++;
countLeft3[union.byte3]++;
}
return(countLeft);
}
int m = (r + l) / 2;
Parallel.Invoke(
() => { countLeft = HistogramByteComponentsParInner(inArray, l, m, parallelThreshold); },
() => { countRight = HistogramByteComponentsParInner(inArray, m + 1, r, parallelThreshold); }
);
// Combine left and right results (reduce step)
for (int i = 0; i < numberOfDigits; i++)
{
for (int j = 0; j < numberOfBins; j++)
{
countLeft[i][j] += countRight[i][j];
}
}
return(countLeft);
}
public static uint[][] HistogramByteComponentsPar(uint[] inArray, Int32 l, Int32 r)
{
const int numberOfBins = 256;
const int numberOfDigits = sizeof(uint);
uint[][] countLeft = new uint[numberOfDigits][];
for (int i = 0; i < numberOfDigits; i++)
{
countLeft[i] = new uint[numberOfBins];
}
if (l > r) // zero elements to compare
{
return(countLeft);
}
if ((r - l + 1) <= ThresholdByteCount)
{
var union = new Algorithm.UInt32ByteUnion();
for (int current = l; current <= r; current++) // Scan the array and count the number of times each digit value appears - i.e. size of each bin
{
union.integer = inArray[current];
countLeft[0][union.byte0]++;
countLeft[1][union.byte1]++;
countLeft[2][union.byte2]++;
countLeft[3][union.byte3]++;
}
return(countLeft);
}
int m = (r + l) / 2;
uint[][] countRight = new uint[numberOfDigits][];
for (int i = 0; i < numberOfDigits; i++)
{
countRight[i] = new uint[numberOfBins];
}
Parallel.Invoke(
() => { countLeft = HistogramByteComponentsPar(inArray, l, m); },
() => { countRight = HistogramByteComponentsPar(inArray, m + 1, r); }
);
// Combine left and right results
for (int i = 0; i < numberOfDigits; i++)
{
for (int j = 0; j < numberOfBins; j++)
{
countLeft[i][j] += countRight[i][j];
}
}
return(countLeft);
}
