RosettaCodeData/Task/Feigenbaum-constant-calcula.../Delphi/feigenbaum-constant-calcula...

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procedure FeigenbaumConstant(Memo: TMemo);
{ Calculate the Feigenbaum constant }
const IMax = 13;
const JMax = 10;
var I,J,K: integer;
var A1,A2,D1,X,Y: double;
var A,D: double;
begin
Memo.Lines.Add('Feigenbaum constant calculation:');
{Set initial starting values for iterations}
A1:=1.0; A2:=0.0; D1:=3.2;
Memo.Lines.Add(' I A D');
for I:=2 to IMax do
begin
{Find next Bifurcation parameter, A}
A:=A1 + (A1 - A2) / D1;
for J:=1 to JMax do
begin
X:=0; Y:=0;
for K:=1 to 1 shl i do
begin
Y:=1 - 2 * y * x;
X:=A - X * X
end;
A:=A - X / Y
end;
{Use current and previous values of A}
{to calculate the Feigenbaum constant D }
D:= (A1 - A2) / (A - A1);
Memo.Lines.Add(Format('%2d %2.8f %2.8f',[I,A,D]));
D1:=D; A2:=A1; A1:=A;
end;
end;