Data commit

Task/Cholesky-decomposition/DWScript/cholesky-decomposition.dw

@@ -0,0 +1,46 @@
+function Cholesky(a : array of Float) : array of Float;
+var
+   i, j, k, n : Integer;
+   s : Float;
+begin
+   n:=Round(Sqrt(a.Length));
+   Result:=new Float[n*n];
+   for i:=0 to n-1 do begin
+      for j:=0 to i do begin
+         s:=0 ;
+         for 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 Float);
+var
+   i, j, n : Integer;
+begin
+   n:=Round(Sqrt(a.Length));
+   for i:=0 to n-1 do begin
+      for j:=0 to n-1 do
+         Print(Format('%2.5f ', [a[i*n+j]]));
+      PrintLn('');
+   end;
+end;
+
+var m1 := new Float[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(c1);
+
+PrintLn('');
+
+var m2 : array of Float := [ 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(c2);