124 lines
3.2 KiB
ObjectPascal
124 lines
3.2 KiB
ObjectPascal
unit varRings2;
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interface
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uses
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BaseVariation, XFormMan;
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type
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TVariationRings2 = class(TBaseVariation)
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private
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FVal, dx: double;
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public
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constructor Create;
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class function GetName: string; override;
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class function GetInstance: TBaseVariation; override;
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function GetNrVariables: integer; override;
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function GetVariableNameAt(const Index: integer): string; override;
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function SetVariable(const Name: string; var value: double): boolean; override;
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function GetVariable(const Name: string; var value: double): boolean; override;
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procedure Prepare; override;
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procedure CalcFunction; override;
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end;
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implementation
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uses
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Math;
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{ TVariationRings2 }
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///////////////////////////////////////////////////////////////////////////////
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procedure TVariationRings2.Prepare;
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const
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EPS = 1E-10;
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begin
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dx := sqr(FVal) + EPS;
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end;
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procedure TVariationRings2.CalcFunction;
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var
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r: double;
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Length: double;
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Angle: double;
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begin
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Length := sqrt(sqr(FTx^) + sqr(FTy^));
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{ // all this range-checking crap only slows us down...
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if (FTx^ < -EPS) or (FTx^ > EPS) or (FTy^ < -EPS) or (FTy^ > EPS) then
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Angle := arctan2(FTx^, FTy^)
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else
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Angle := 0.0;
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} // ...and besides, we don't need arctan() if we have Length!
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// dx := sqr(FVal) + EPS; - we can precalc it!!!
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// r := Length + dx - System.Int((Length + dx)/(2 * dx)) * 2 * dx - dx + Length * (1-dx);
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// ^^^^......he he, lots of useless calculations......^^^^
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r := vvar * (2 - dx * (System.Int((Length/dx + 1)/2) * 2 / Length + 1));
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FPx^ := FPx^ + r * FTx^;
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FPy^ := FPy^ + r * FTy^;
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end;
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///////////////////////////////////////////////////////////////////////////////
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constructor TVariationRings2.Create;
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begin
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FVal := Random * 2;
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end;
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///////////////////////////////////////////////////////////////////////////////
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class function TVariationRings2.GetInstance: TBaseVariation;
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begin
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Result := TVariationRings2.Create;
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end;
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///////////////////////////////////////////////////////////////////////////////
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class function TVariationRings2.GetName: string;
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begin
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Result := 'rings2';
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end;
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///////////////////////////////////////////////////////////////////////////////
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function TVariationRings2.GetVariableNameAt(const Index: integer): string;
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begin
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case Index Of
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0: Result := 'rings2_val';
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else
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Result := '';
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end
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end;
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///////////////////////////////////////////////////////////////////////////////
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function TVariationRings2.SetVariable(const Name: string; var value: double): boolean;
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begin
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Result := False;
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if Name = 'rings2_val' then begin
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FVal := Value;
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Result := True;
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end
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end;
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///////////////////////////////////////////////////////////////////////////////
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function TVariationRings2.GetNrVariables: integer;
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begin
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Result := 1
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end;
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///////////////////////////////////////////////////////////////////////////////
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function TVariationRings2.GetVariable(const Name: string; var value: double): boolean;
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begin
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Result := False;
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if Name = 'rings2_val' then begin
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Value := FVal;
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Result := True;
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end
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end;
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///////////////////////////////////////////////////////////////////////////////
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initialization
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RegisterVariation(TVariationClassLoader.Create(TVariationRings2));
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end.
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