Moving source code

1 files changed, 64 insertions, 0 deletions

diff --git a/src/c/elementaryFunctions/log/zlogs.c b/src/c/elementaryFunctions/log/zlogs.c
new file mode 100644
index 00000000..dd0792a9
--- /dev/null
+++ b/src/c/elementaryFunctions/log/zlogs.c
@@ -0,0 +1,64 @@
+/*
+ *  Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+ *  Copyright (C) 2007-2008 - INRIA - Bruno JOFRET
+ *
+ *  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"
+
+doubleComplex	zlogs(doubleComplex in) {
+  static double sR2	= 1.41421356237309504;
+
+  double _RealIn = zreals(in);
+  double _ImgIn = zimags(in);
+
+  double _RealOut = 0;
+  double _ImgOut = 0;
+
+  double RMax = getOverflowThreshold();
+  double LInf = sqrt(getUnderflowThreshold());
+  double LSup = sqrt(0.5 * RMax);
+
+  double AbsReal = fabs(_RealIn);
+  double AbsImg	= fabs(_ImgIn);
+
+  _ImgOut = atan2(_ImgIn, _RealIn);
+
+  if(_ImgIn > _RealIn)
+    {/* switch Real part and Imaginary part */
+      double Temp	= AbsReal;
+      AbsReal		= AbsImg;
+      AbsImg		= Temp;
+    }
+
+  if((0.5 <= AbsReal) && (AbsReal <= sR2))
+    _RealOut = 0.5 * dlog1ps((AbsReal - 1) * (AbsReal + 1) + AbsImg * AbsImg);
+  else if(LInf < AbsImg && AbsReal < LSup)
+    _RealOut = 0.5 * dlogs(AbsReal * AbsReal + AbsImg * AbsImg);
+  else if(AbsReal > RMax)
+    _RealOut = AbsReal;
+  else
+    {
+      double Temp = dpythags(AbsReal, AbsImg);
+      if(Temp <= RMax)
+	{
+	  _RealOut = dlogs(Temp);
+	}
+      else /* handle rare spurious overflow with : */
+	{
+	  double Temp2 = AbsImg/AbsReal;
+	  _RealOut = dlogs(AbsReal) + 0.5 * dlog1ps(Temp2 * Temp2);
+	}
+    }
+  return DoubleComplex(_RealOut, _ImgOut);
+}