public static void Parallel(int[] e)
{
Campy.Parallel.Sticky(e);
int N = e.Length;
int log2n = Bithacks.FloorLog2(N);
for (int level = 1; level <= log2n; level++)
{
int step = Bithacks.Power2(level);
Campy.Parallel.For(N / step, idx =>
{
var i = step * (idx + 1) - 1;
e[i] = e[i - step / 2] + e[i];
});
}
Campy.Sequential.For(1, idx => { e[N - 1] = 0; });
for (int level = log2n; level > 0; level--)
{
int step = Bithacks.Power2(level);
Campy.Parallel.For(N / step, idx =>
{
var i = step * (idx + 1) - 1;
var l = e[i - step / 2];
var r = e[i];
e[i] = r + l;
e[i - step / 2] = r;
});
}
Campy.Parallel.Sync();
}
public static int xFloorLog2(uint x)
{
x |= (x >> 1);
x |= (x >> 2);
x |= (x >> 4);
x |= (x >> 8);
x |= (x >> 16);
return(Bithacks.Ones(x) - 1);
}
public static int CeilingLog2(int v)
{
int r = Bithacks.FloorLog2(v);
if (r < 0)
{
return(r);
}
if (v != (uint)Bithacks.Power2((uint)r))
{
return(r + 1);
}
else
{
return(r);
}
}