private int GetPseudoRandomBlock(float stepFactor, float theta2)
{
var startIdx = AsyncRandom.GetRandomBlockIdx(random, id, shared.BlockLock);
var currentIdx = startIdx;
var currentBlockValue = GetMaxAbsBlockValue(shared, shared.ActiveSet[currentIdx], stepFactor, theta2);
var searchLength = (int)(shared.ActiveSet.Count / totalNodes * searchPercentage);
for (int i = 1; i < searchLength; i++)
{
var checkIdx = (startIdx + i) % shared.ActiveSet.Count;
if (Thread.VolatileRead(ref shared.BlockLock[checkIdx]) == 0)
{
//check if next block is better than current block
var checkBlockValue = GetMaxAbsBlockValue(shared, shared.ActiveSet[checkIdx], stepFactor, theta2);
if (currentBlockValue < checkBlockValue)
{
if (Interlocked.CompareExchange(ref shared.BlockLock[checkIdx], this.id, 0) == 0)
{
//locking of better block successful, continue
Thread.VolatileWrite(ref shared.BlockLock[currentIdx], 0);
currentIdx = checkIdx;
currentBlockValue = checkBlockValue;
}
else
{
//some other thread conflicted with ours, jump to another random place
startIdx = random.Next(0, shared.ActiveSet.Count);
}
}
}
}
return(currentIdx);
}
