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/*
* Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
* Copyright (C) 2007-2008 - INRIA - Bruno JOFRET
* Copyright (C) Bruno Pincon
*
* This file must be used under the terms of the CeCILL.
* This source file is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at
* http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
*
*/
#include <math.h>
#include "log.h"
#include "lapack.h"
#include "log1p.h"
#include "pythag.h"
floatComplex clogs(floatComplex in) {
static float sR2 = 1.41421356237309504f;
float _RealIn = creals(in);
float _ImgIn = cimags(in);
float _RealOut = 0;
float _ImgOut = 0;
float RMax = (float) getOverflowThreshold();
float LInf = sqrtf((float) getUnderflowThreshold());
float LSup = sqrtf(0.5f * RMax);
float AbsReal = fabsf(_RealIn);
float AbsImg = fabsf(_ImgIn);
_ImgOut = atan2f(_ImgIn, _RealIn);
if(_ImgIn > _RealIn)
{/* switch Real part and Imaginary part */
float Temp = AbsReal;
AbsReal = AbsImg;
AbsImg = Temp;
}
if((0.5 <= AbsReal) && (AbsReal <= sR2))
_RealOut = 0.5f * slog1ps((AbsReal - 1.0f) * (AbsReal + 1.0f) + AbsImg * AbsImg);
else if(LInf < AbsImg && AbsReal < LSup)
_RealOut = 0.5f * slogs(AbsReal * AbsReal + AbsImg * AbsImg);
else if(AbsReal > RMax)
_RealOut = AbsReal;
else
{
float Temp = spythags(AbsReal, AbsImg);
if(Temp <= RMax)
{
_RealOut = slogs(Temp);
}
else /* handle rare spurious overflow with : */
{
float Temp2 = AbsImg/AbsReal;
_RealOut = slogs(AbsReal) + 0.5f * slog1ps(Temp2 * Temp2);
}
}
return FloatComplex(_RealOut, _ImgOut);
}
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