// <copyright file="ParallelTest.cs" company="Math.NET">
// Math.NET Numerics, part of the Math.NET Project
// http://mathnet.opensourcedotnet.info
//
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namespace MathNet.Numerics.UnitTests.ThreadingTests
{
    using System;
    using System.Threading;
    using MbUnit.Framework;
    using Threading;

    [TestFixture]
    public class ParallelTest
    {
        [Test, ApartmentState(ApartmentState.MTA)]
        [Column(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 101)]
        public void ParallelForInvokesEveryItemOnceMTAOnePerCore(int count)
        {
            var items = new int[count];

            // ensure One-Per-Core
            ThreadQueue.Start(Environment.ProcessorCount);

            Parallel.For(0, count, i => items[i]++);
            Parallel.For(0, count, i => items[i] += 1000);

            for (int i = 0; i < items.Length; i++)
            {
                Assert.AreEqual(1001, items[i], i.ToString());
            }
        }

        [Test, ApartmentState(ApartmentState.STA)]
        [Column(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 101)]
        public void ParallelForInvokesEveryItemOnceSTAOnePerCore(int count)
        {
            var items = new int[count];

            // ensure One-Per-Core
            ThreadQueue.Start(Environment.ProcessorCount);

            Parallel.For(0, count, i => items[i]++);
            Parallel.For(0, count, i => items[i] += 1000);

            for (int i = 0; i < items.Length; i++)
            {
                Assert.AreEqual(1001, items[i], i.ToString());
            }
        }

        [Test, ApartmentState(ApartmentState.MTA)]
        [Column(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 101)]
        public void ParallelForInvokesEveryItemOnceMTATwoPerCore(int count)
        {
            var items = new int[count];

            // ensure Two-Per-Core
            ThreadQueue.Start(2 * Environment.ProcessorCount);

            Parallel.For(0, count, i => items[i]++);
            Parallel.For(0, count, i => items[i] += 1000);

            for (int i = 0; i < items.Length; i++)
            {
                Assert.AreEqual(1001, items[i], i.ToString());
            }
        }

        [Test, ApartmentState(ApartmentState.STA)]
        [Column(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 101)]
        public void ParallelForInvokesEveryItemOnceSTATwoPerCore(int count)
        {
            var items = new int[count];

            // ensure Two-Per-Core
            ThreadQueue.Start(2 * Environment.ProcessorCount);

            Parallel.For(0, count, i => items[i]++);
            Parallel.For(0, count, i => items[i] += 1000);

            for (int i = 0; i < items.Length; i++)
            {
                Assert.AreEqual(1001, items[i], i.ToString());
            }
        }

        [Test, ApartmentState(ApartmentState.MTA)]
        public void DoesNotGetConfusedByMultipleStartShutdown()
        {
            ThreadQueue.Shutdown();
            ThreadQueue.Shutdown();

            ThreadQueue.Start(2);
            Assert.AreEqual(2, ThreadQueue.ThreadCount);

            ThreadQueue.Start(2);
            Assert.AreEqual(2, ThreadQueue.ThreadCount);

            ThreadQueue.Start(4);
            Assert.AreEqual(4, ThreadQueue.ThreadCount);

            ThreadQueue.Shutdown();
            ThreadQueue.Start();
            Assert.AreEqual(4, ThreadQueue.ThreadCount);

            ThreadQueue.Start(2);
            Assert.AreEqual(2, ThreadQueue.ThreadCount);

            var items = new int[50];

            Parallel.For(0, items.Length, i => items[i]++);
            Parallel.For(0, items.Length, i => items[i] += 1000);

            ThreadQueue.Shutdown();

            for(int i = 0; i < items.Length; i++)
            {
                Assert.AreEqual(1001, items[i], i.ToString());
            }
        }
    }
}