Data update

Task/Gamma-function/Pascal-P/gamma-function.pas

@@ -0,0 +1,48 @@
+program gammafunction(output);
+(* Gamma function *)
+
+const
+  pi = 3.1415926535897932384626433832795;
+
+var
+  x: real;
+
+  function lngamma(z: real): real;
+  var
+    lz: array[0..6] of real;
+    a, b: real;
+    i: integer;
+  begin
+    lz[0] := 1.00000000019001;
+    lz[1] := 76.1800917294715;
+    lz[2] := -86.5053203294168;
+    lz[3] := 24.0140982408309;
+    lz[4] := -1.23173957245015;
+    lz[5] := 0.0012086509738662;
+    lz[6] := -0.000005395239385;
+    if (z < 0.5) then
+      lngamma := ln(pi / sin(pi * z)) - lngamma(1.0 - z)
+    else
+    begin
+      z := z - 1.0;
+      b := z + 5.5;
+      a := lz[0];
+      for i := 1 to 6 do
+        a := a + lz[i] / (z + i);
+      lngamma := (ln(sqrt(2 * pi)) + ln(a) - b) + ln(b) * (z + 0.5);
+    end;
+  end;
+
+  function gamma(z: real): real;
+  begin
+    gamma := exp(lngamma(z));
+  end;
+
+begin
+  x := 0.1;
+  while x <= 2.05 do
+  begin
+    writeln(x, ' ', gamma(x));
+    x := x + 0.1;
+  end;
+end.