Add SIMD CSharp Mandlebrot (#428)

if rust gets SIMD so do we

Co-authored-by: hanabi1224 <[email protected]>

Author: xentripetal

bench/algorithm/mandelbrot/4.cs

@@ -0,0 +1,105 @@
+using System.Runtime.CompilerServices;
+using System.Runtime.Intrinsics;
+using System.Security.Cryptography;
+using System.Text;
+using System;
+
+public class MandelBrot
+{
+    public static void Main(string[] args)
+    {
+        var size = args.Length == 0 ? 200 : int.Parse(args[0]);
+        size = (size + 7) / 8 * 8;
+        var chunkSize = size / 8;
+        var inv = 2.0 / size;
+        Console.WriteLine($"P4\n{size} {size}");
+
+        var xloc = new Vector512<double>[chunkSize];
+        for (var i = 0; i < chunkSize; i++)
+        {
+            var array = new double[8];
+            var offset = i * 8;
+            for (var j = 0; j < 8; j++)
+            {
+                array[j] = (offset + j) * inv - 1.5;
+            }
+            xloc[i] = Vector512.Create(array);
+        }
+
+        var data = new byte[size * chunkSize];
+
+        for (var y = 0; y < size; y++)
+        {
+            var ci = y * inv - 1.0;
+            for (var x = 0; x < chunkSize; x++)
+            {
+                var r = mbrot8(xloc[x], ci);
+                if (r > 0)
+                {
+                    data[y * chunkSize + x] = r;
+                }
+            }
+        }
+
+        using var hasher = MD5.Create();
+        var hash = hasher.ComputeHash(data);
+        Console.WriteLine(ToHexString(hash));
+    }
+    
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    static byte mbrot8(Vector512<double> cr, double civ)
+    {
+        Vector512<double> ci = Vector512.Create(civ);
+        Vector512<double> zr = Vector512.Create(0.0);
+        Vector512<double> zi = Vector512.Create(0.0);
+        Vector512<double> tr = Vector512.Create(0.0);
+        Vector512<double> ti = Vector512.Create(0.0);
+        Vector512<double> absz = Vector512.Create(0.0);
+        
+        for (var _i = 0; _i < 10; _i++)
+        {
+            for (var _j = 0; _j < 5; _j++)
+            {
+                zi = (zr + zr) * zi + ci;
+                zr = tr - ti + cr;
+                tr = zr * zr;
+                ti = zi * zi;
+            }
+            absz = tr + ti;
+            var terminate = true;
+            for (var i = 0; i < 8; i++)
+            {
+                if (absz[i] <= 4.0)
+                {
+                    terminate = false;
+                    break;
+                }
+            }
+            if (terminate)
+            {
+                return 0;
+            }
+        }
+
+        var accu = (byte)0;
+        for (var i = 0; i < 8; i++)
+        {
+            if (absz[i] <= 4.0)
+            {
+                accu |= (byte)(0x80 >> i);
+            }
+        }
+        return accu;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    static string ToHexString(byte[] ba)
+    {
+        StringBuilder hex = new StringBuilder(ba.Length * 2);
+        foreach (byte b in ba)
+        {
+            hex.AppendFormat("{0:x2}", b);
+        }
+        return hex.ToString();
+    }
+}

bench/bench_csharp.yaml

@@ -41,6 +41,7 @@ problems:
       - 1.cs
       - 2.cs
       - 3.cs
+      - 4.cs
   - name: json-serde
     source:
       - 1.cs