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// Upgraded to Delphi 2009: Sebastian Zierer
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(* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is TurboPower SysTools
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*
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* The Initial Developer of the Original Code is
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* TurboPower Software
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*
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* Portions created by the Initial Developer are Copyright (C) 1996-2002
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* ***** END LICENSE BLOCK ***** *)
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{*********************************************************}
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{* SysTools: StMath.pas 4.04 *}
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{*********************************************************}
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{* SysTools: Miscellaneous math functions *}
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{*********************************************************}
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{$I StDefine.inc}
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unit StMath;
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interface
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uses
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Windows,
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SysUtils, StDate, StBase, StConst;
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const
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RadCor : Double = 57.29577951308232; {number of degrees in a radian}
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{$IFNDEF UseMathUnit}
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function IntPower(Base : Extended; Exponent : Integer): Extended;
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{-Raise Base to an integral power Exponent}
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function Power(Base, Exponent : Extended) : Extended;
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{-Raise Base to an arbitrary power Exponent}
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{$ENDIF}
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function StInvCos(X : Double): Double;
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{-Returns the ArcCos of Y}
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function StInvSin(Y : Double): Double;
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{-Returns the ArcSin of Y}
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function StInvTan2(X, Y : Double) : Double;
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{-Returns the ArcTangent of Y / X}
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function StTan(A : Double) : Double;
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{-Returns the Tangent of A}
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{-------------------------------------------------------}
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implementation
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{$IFNDEF UseMathUnit}
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function IntPower(Base : Extended; Exponent : Integer): Extended;
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var
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Y : Integer;
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begin
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Y := Abs(Exponent);
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Result := 1;
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while (Y > 0) do begin
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while (not Odd(Y)) do begin
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Y := Y shr 1;
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Base := Base * Base;
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end;
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Dec(Y);
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Result := Result * Base;
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end;
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if (Exponent < 0) then
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Result := 1 / Result;
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end;
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{-------------------------------------------------------}
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function Power(Base, Exponent: Extended): Extended;
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begin
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if (Exponent = 0) then
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Result := 1
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else if (Base = 0) and (Exponent > 0) then
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Result := 0
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else if (Frac(Exponent) = 0) and (Abs(Exponent) <= MaxInt) then
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Result := IntPower(Base, Trunc(Exponent))
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else
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Result := Exp(Exponent * Ln(Base));
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end;
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{$ENDIF}
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{-------------------------------------------------------}
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function StTan(A : Double) : Double;
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var
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C, S : Double;
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begin
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C := Cos(A);
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S := Sin(A);
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if (Abs(C) >= 5E-12) then
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Result := S / C
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else if (C < 0) then
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Result := 5.0e-324
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else
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Result := 1.7e+308;
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end;
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{-------------------------------------------------------}
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function StInvTan2(X, Y : Double) : Double;
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begin
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if (Abs(X) < 5.0E-12) then begin
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if (X < 0) then
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Result := 3 * Pi / 2
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else
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Result := Pi / 2;
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end else begin
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Result := ArcTan(Y / X);
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if (X < 0) then
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Result := Result + Pi
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else if (Y < 0) then
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Result := Result + 2 * Pi;
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end;
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end;
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{-------------------------------------------------------}
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function StInvSin(Y : Double): Double;
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begin
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if (Abs(Abs(Y) - 1) > 5.0E-12) then
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Result := ArcTan(Y / Sqrt(1 - Y * Y))
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else begin
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if (Y < 0) then
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Result := 3 * Pi / 2
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else
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Result := Pi / 2;
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end;
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end;
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{-------------------------------------------------------}
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function StInvCos(X : Double): Double;
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begin
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if (Abs(Abs(X) - 1) > 5.0E-12) then
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Result := (90 / RadCor) - ArcTan(X / Sqrt(1 - X * X))
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else begin
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if ((X - Pi / 2) > 0) then
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Result := 0
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else
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Result := Pi;
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end;
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end;
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end.
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