Data update

Task/Cholesky-decomposition/PascalABC.NET/cholesky-decomposition.pas

@@ -0,0 +1,51 @@
+function Cholesky(a: array of real): array of real;
+begin
+  var n := Round(Sqrt(a.Length));
+  Result := new real[n * n];
+  for var i := 0 to n - 1 do
+  begin
+    for var j := 0 to i do
+    begin
+      var s := 0.0;
+      for var k := 0 to j - 1 do
+        s += Result[i * n + k] * Result[j * n + k];
+      if i = j then
+        Result[i * n + j] := Sqrt(a[i * n + i] - s)
+      else Result[i * n + j] := 1 / Result[j * n + j] * (a[i * n + j] - s);
+    end;
+  end;
+end;
+
+procedure ShowMatrix(a: array of real);
+begin
+  var n := Round(Sqrt(a.Length));
+  for var i := 0 to n - 1 do
+  begin
+    for var j := 0 to n - 1 do
+      write(a[i * n + j]:10:5);
+    PrintLn('');
+  end;
+end;
+
+begin
+  var m1 := new real[9];
+  m1 := |25.0, 15.0, -5.0,
+         15.0, 18.0,  0.0,
+         -5.0,  0.0, 11.0 |;
+  var c1 := Cholesky(m1);
+  ShowMatrix(m1);
+  println('=>');
+  ShowMatrix(c1);
+
+  PrintLn('');
+
+  var m2: array of real :=
+  |18.0, 22.0,  54.0,  42.0,
+  22.0, 70.0,  86.0,  62.0,
+  54.0, 86.0, 174.0, 134.0,
+  42.0, 62.0, 134.0, 106.0 |;
+  var c2 := Cholesky(m2);
+  Showmatrix(m2);
+  println('=>');
+  ShowMatrix(c2);
+end.