public static BigNumber AddParallel(params BigNumber[] numbers)
{
if (numbers.Length <= 1)
{
throw new InvalidOperationException("Array too small!");
}
var first = numbers[0];
var firstQueue = new BigNumberQueue();
for (var i = 0; i < first.Digits.Length; ++i)
{
firstQueue.Enqueue(new Tuple <int, int>(i, first.Digits[i]));
}
firstQueue.Done = true;
var queues = new BigNumberQueue[numbers.Length];
queues[0] = firstQueue;
for (var i = 1; i < numbers.Length; ++i)
{
queues[i] = AddParallel(queues[i - 1], numbers[i]);
}
while (!queues[numbers.Length - 1].Done)
{
}
var result = new List <int>();
while (queues[numbers.Length - 1].Count > 0)
{
result.Add(queues[numbers.Length - 1].Dequeue().Item2);
}
result.Reverse();
return(new BigNumber(result.ToArray()));
}
private static BigNumberQueue AddParallel(BigNumberQueue a, BigNumber b)
{
var result = new BigNumberQueue();
Task.Factory.StartNew(() =>
{
var transport = 0;
int i;
for (i = 0; i < b.Digits.Length; ++i)
{
while (!a.Done && (a.Count == 0)) // Waiting for a digit.
{
}
if (a.Done && (a.Count == 0)) // Finished all digits from "a", just adding "b".
{
lock (result)
{
result.Enqueue(new Tuple <int, int>(i, (transport + b.Digits[i]) % 10));
transport = (transport + b.Digits[i]) / 10;
}
}
if (a.Count > 0) // We have a digit from a previous computation.
{
lock (a)
{
var digit = a.Dequeue();
if (digit.Item1 != i)
{
throw new InvalidOperationException("Out of order!");
}
lock (result)
{
result.Enqueue(new Tuple <int, int>(i, (transport + digit.Item2 + b.Digits[i]) % 10));
transport = (transport + digit.Item2 + b.Digits[i]) / 10;
}
}
}
}
while (!(a.Done && (a.Count == 0))) // Finished all digits from "b", just adding "a".
{
if (a.Count > 0)
{
lock (a)
{
var digit = a.Dequeue();
lock (result)
{
result.Enqueue(new Tuple <int, int>(i, (transport + digit.Item2) % 10));
transport = (transport + digit.Item2) / 10;
i++;
}
}
}
}
if (transport > 0) // We can have at most one extra digit in the transport variable.
{
lock (result)
{
result.Enqueue(new Tuple <int, int>(i, transport));
}
}
result.Done = true; // Signal that we have finished the computations.
});
return(result);
}
