/// <summary>
/// This method returns the calculated amount of subbatches which is assumed to be the opimum.
/// To determine all possible subbatches, the batchsize must be factorized into its primes.
/// </summary>
/// <param name="keyTranslator"></param>
/// <returns></returns>
public int GetAmountOfSubbatches(IKeyTranslator keyTranslator)
{
if (this.keyTranslator != keyTranslator)
{
//init code:
this.keyTranslator = keyTranslator;
//Find factors of OpenCL batch size:
List <Msieve.Factor> factors = Msieve.TrivialFactorization(keyTranslator.GetOpenCLBatchSize());
amountOfSubbatchesFactors = new List <int>();
foreach (var fac in factors)
{
for (int i = 0; i < fac.count; i++)
{
amountOfSubbatchesFactors.Add((int)fac.factor);
}
}
amountOfSubbatches = keyTranslator.GetOpenCLBatchSize();
batchSizeFactors = new List <int>();
DecreaseAmountOfSubbatches();
lastDuration = TimeSpan.MaxValue;
optimisticDecrease = false;
lastStepIncrease = false;
if (openCLMode == 1) //normal load
{
DecreaseAmountOfSubbatches();
}
}
return(amountOfSubbatches);
}
private void DecreaseAmountOfSubbatches()
{
if (amountOfSubbatchesFactors.Count < 1)
{
return;
}
if (keyTranslator.GetOpenCLBatchSize() / amountOfSubbatches >= maxNumberOfThreads) //not more than MAXNUMBEROFTHREADS threads concurrently
{
return;
}
do
{
int maxElement = amountOfSubbatchesFactors.Max();
batchSizeFactors.Add(maxElement);
amountOfSubbatchesFactors.Remove(maxElement);
amountOfSubbatches = amountOfSubbatchesFactors.Aggregate(1, (current, i) => current * i);
} while (keyTranslator.GetOpenCLBatchSize() / amountOfSubbatches < (256 * 256)); //each batch should have at least size 256*256
}