diff options
Diffstat (limited to '2.3-1/src/c/elementaryFunctions/log/clogs.c')
-rw-r--r-- | 2.3-1/src/c/elementaryFunctions/log/clogs.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/2.3-1/src/c/elementaryFunctions/log/clogs.c b/2.3-1/src/c/elementaryFunctions/log/clogs.c new file mode 100644 index 00000000..3b9f6911 --- /dev/null +++ b/2.3-1/src/c/elementaryFunctions/log/clogs.c @@ -0,0 +1,65 @@ +/*
+ * 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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