Anonymous user
Julia set: Difference between revisions
→{{header|C sharp|C#}}
Line 253:
}
</lang>
C# also makes it relatively easy to do a multi-threaded version, which should run faster than the above:
<lang csharp>
public struct CalculatedPoint
{
public int x;
public int y;
public int i;
}
static void MultiThreaded()
{
const int w = 800;
const int h = 600;
const int zoom = 1;
const int maxiter = 255;
const int moveX = 0;
const int moveY = 0;
const double cX = -0.7;
const double cY = 0.27015;
// Precalculate a pallette of 256 colors
var colors = (from c in Enumerable.Range(0, 256)
select Color.FromArgb((c >> 5) * 36, (c >> 3 & 7) * 36, (c & 3) * 85)).ToArray();
// The "AsParallel" below invokes PLINQ, making evaluation parallel using as many cores as
// are available.
var calculatedPoints = Enumerable.Range(0, w * h).AsParallel().Select(xy =>
{
double zx, zy, tmp;
int x, y;
int i = maxiter;
y = xy / w;
x = xy % w;
zx = 1.5 * (x - w / 2) / (0.5 * zoom * w) + moveX;
zy = 1.0 * (y - h / 2) / (0.5 * zoom * h) + moveY;
while (zx * zx + zy * zy < 4 && i > 1)
{
tmp = zx * zx - zy * zy + cX;
zy = 2.0 * zx * zy + cY;
zx = tmp;
i -= 1;
}
return new CalculatedPoint { x = x, y = y, i = i };
});
// Bitmap is not multi-threaded, so main thread needs to read in the results as they
// come in and plot the pixels.
var bitmap = new Bitmap(w, h);
foreach (CalculatedPoint cp in calculatedPoints)
bitmap.SetPixel(cp.x, cp.y, colors[cp.i]);
bitmap.Save("julia-set-multi.png");
}</lang>
=={{header|COBOL}}==
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