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(uint v)
{
int r = Bithacks.FloorLog2(v);
if (r < 0)
{
return(r);
}
if (v != (uint)Bithacks.Power2((uint)r))
{
return(r + 1);
}
else
{
return(r);
}
}
static int Max(int[] data)
{
int n = data.Length;
int result = 0;
{
for (int level = 1; level <= Bithacks.Log2(n); level++)
{
int step = Bithacks.Power2(level);
Campy.Parallel.For(n / step, idx =>
{
var i = step * idx;
data[i] = data[i] < data[i + step / 2] ? data[i + step / 2] : data[i];
});
}
result = data[0];
}
return(result);
}
static void Sum2()
{
int n = Bithacks.Power2(10);
float result_gpu = 0;
float result_cpu = 0;
{
List <float> data = Enumerable.Range(0, n).Select(i => ((float)i) / 10).ToList();
for (int level = 1; level <= Bithacks.Log2(n); level++)
{
int step = Bithacks.Power2(level);
for (int idx = 0; idx < n / step; idx++)
{
var i = step * idx;
data[i] = data[i] + data[i + step / 2];
}
}
result_cpu = data[0];
}
{
List <float> data = Enumerable.Range(0, n).Select(i => ((float)i) / 10).ToList();
for (int level = 1; level <= Bithacks.Log2(n); level++)
{
int step = Bithacks.Power2(level);
Campy.Parallel.For(n / step, idx =>
{
var i = step * idx;
data[i] = data[i] + data[i + step / 2];
});
}
result_gpu = data[0];
}
if (result_gpu != result_cpu)
{
throw new Exception();
}
}
