internal static void WarpShuffleDownKernel(
Index1 index,
ArrayView <int> data,
int shiftAmount)
{
data[index] = Warp.ShuffleDown(Warp.LaneIdx, shiftAmount);
}
internal static void WarpShuffleDownKernel(
Index1D index,
ArrayView1D <int, Stride1D.Dense> data,
int shiftAmount)
{
data[index] = Warp.ShuffleDown(Warp.LaneIdx, shiftAmount);
}
/// <summary>
/// Performs a shuffle operation. It returns the value of the variable
/// in the context of the lane with the id current lane + delta.
/// </summary>
/// <param name="variable">The source variable to shuffle.</param>
/// <param name="delta">The delta to add to the current lane.</param>
/// <returns>The value of the variable in the scope of the desired lane.</returns>
public unsafe long ShuffleDown(long variable, int delta)
{
var result = new Int2();
var ptr = (Int2 *)&variable;
result.X = Warp.ShuffleDown(ptr->X, delta);
result.Y = Warp.ShuffleDown(ptr->Y, delta);
return(*(long *)&result);
}
/// <summary>
/// Performs a shuffle operation. It returns the value of the variable
/// in the context of the lane with the id current lane + delta.
/// </summary>
/// <param name="variable">The source variable to shuffle.</param>
/// <param name="delta">The delta to add to the current lane.</param>
/// <returns>The value of the variable in the scope of the desired lane.</returns>
public long ShuffleDown(long variable, int delta)
{
var source = Unsafe.As <long, Int2>(ref variable);
var result = new Int2()
{
X = Warp.ShuffleDown(source.X, delta),
Y = Warp.ShuffleDown(source.Y, delta),
};
return(Unsafe.As <Int2, long>(ref result));
}
/// <summary>
/// Explicitly grouped kernels receive an index type (first parameter) of type:
/// <see cref="GroupedIndex"/>, <see cref="GroupedIndex2"/> or <see cref="GroupedIndex3"/>.
/// Note that you can use warp-shuffle functionality only within
/// explicitly-grouped kernels. Previously, it was required to use one of the predefined
/// shuffle overloads. If the desired function was not available, you had to create a
/// custom shuffle operation implementation. The current ILGPU version emits the required
/// shuffle instructions (even for complex data types) automatically.
/// </summary>
/// <param name="index">The current thread index.</param>
/// <param name="dataView">The view pointing to our memory buffer.</param>
static void ShuffleDownKernel(
ArrayView <int> dataView) // A view to a chunk of memory (1D in this case)
{
// Use native shuffle-down functionality to shuffle the
// given value by a delta of 2 lanes
int value = Group.IdxX;
value = Warp.ShuffleDown(value, 2);
dataView[Grid.GlobalIndex.X] = value;
}
public static T Reduce <T, TReduction>(T value)
where T : unmanaged
where TReduction : IScanReduceOperation <T>
{
TReduction reduction = default;
for (int laneOffset = Warp.WarpSize / 2; laneOffset > 0; laneOffset >>= 1)
{
var shuffled = Warp.ShuffleDown(value, laneOffset);
value = reduction.Apply(value, shuffled);
}
return(value);
}
/// <summary>
/// Explicitly grouped kernels receive an index type (first parameter) of type:
/// <see cref="GroupedIndex"/>, <see cref="GroupedIndex2"/> or <see cref="GroupedIndex3"/>.
/// Note that you can use warp-shuffle functionality only within
/// explicitly-grouped kernels.
/// </summary>
/// <param name="index">The current thread index.</param>
/// <param name="dataView">The view pointing to our memory buffer.</param>
static void ShuffleDownKernel(
GroupedIndex index, // The grouped thread index (1D in this case)
ArrayView <int> dataView) // A view to a chunk of memory (1D in this case)
{
// Compute the global 1D index for accessing the data view
var globalIndex = index.ComputeGlobalIndex();
// Use native shuffle-down functionality to shuffle the
// given value by a delta of 2 lanes
int value = index.GroupIdx;
value = Warp.ShuffleDown(value, 2);
dataView[globalIndex] = value;
}