FPRNG : TtdMinStandardPRNG;
FTable : array [0..54] of double;
protected
procedure agSetSeed(aValue : longint);
procedure agInitTable;
public
constructor Create(aSeed : longint);
destructor Destroy; override
function AsDouble : double; override
property Seed : longint write agSetSeed;
end;
constructor TtdAdditiveGenerator.Create(aSeed : longint);
begin
inherited Create;
FPRNG := TtdMinStandardPRNG.Create(aSeed);
agInitTable;
FInx1 := 54;
FInx2 := 23;
end;
destructor TtdAdditiveGenerator.Destroy;
begin
FPRNG.Free
inherited Destroy;
end;
procedure TtdAdditiveGenerator.agSetSeed(aValue : longint);
begin
FPRNG.Seed := aValue;
agInitTable;
end;
procedure TtdAdditiveGenerator.agInitTable;
var
i : integer;
begin
for i := 54 downto 0 do
FTable[i] := FPRNG.AsDouble;
end;
function TtdAdditiveGenerator.AsDouble : double;
begin
Result := FTable[FInx1] + FTable[FInx2];
if (Result >= 1.0) then
Result := Result - 1.0;
FTable[FInx1] := Result;
inc(FInx1);
if (FInx1 >= 55) then
FInx1 := 0;
inc(FInx2);
if (FInx2 >= 55) then
FInx2 := 0;
end;