Data update

Task/Gamma-function/PascalABC.NET/gamma-function.pas

@@ -0,0 +1,28 @@
+const
+  g = 7;
+  p: array of real =
+        (0.99999999999980993, 676.5203681218851, -1259.1392167224028,
+	     771.32342877765313, -176.61502916214059, 12.507343278686905,
+	     -0.13857109526572012, 9.9843695780195716e-6, 1.5056327351493116e-7);
+
+function Gamma(z: Complex): Complex;
+begin
+  if (z.Real < 0.5) then
+  begin
+    result := pi / (Sin(pi * z) * Gamma(1 - z));
+    exit;
+  end
+  else
+  begin
+    z -= 1;
+    var x: Complex := p[0];
+    for var i := 1 to g + 1 do x += p[i] / (z + i);
+    var t := z + g + 0.5;
+    result := Sqrt(2 * pi) * (Power(t, z + 0.5)) * Exp(-t) * x;
+  end;
+end;
+
+begin
+  writeln('z          Lanczos');
+  for var i := 1 to 10 do writeln(i / 3:6:4, gamma(i / 3):25);
+end.