From 277d1edfa17bf3719d90ddbac8e31f6181e952c3 Mon Sep 17 00:00:00 2001
From: Sandeep Gupta
Date: Sun, 18 Jun 2017 23:55:40 +0530
Subject: First commit
---
src/c/elementaryFunctions/acos/cacoss.c | 147 ++++++++++++++++++++++++++++++++
1 file changed, 147 insertions(+)
create mode 100644 src/c/elementaryFunctions/acos/cacoss.c
(limited to 'src/c/elementaryFunctions/acos/cacoss.c')
diff --git a/src/c/elementaryFunctions/acos/cacoss.c b/src/c/elementaryFunctions/acos/cacoss.c
new file mode 100644
index 00000000..97420313
--- /dev/null
+++ b/src/c/elementaryFunctions/acos/cacoss.c
@@ -0,0 +1,147 @@
+/*
+ * 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
+ *
+ */
+
+/*
+ * This fonction is a translation of fortran wacos write by Bruno Pincon <Bruno.Pincon@iecn.u-nancy.fr>
+ * REFERENCE
+ * This is a Fortran-77 translation of an algorithm by
+ * T.E. Hull, T. F. Fairgrieve and P.T.P. Tang which
+ * appears in their article :
+ * "Implementing the Complex Arcsine and Arccosine
+ * Functions Using Exception Handling", ACM, TOMS,
+ * Vol 23, No. 3, Sept 1997, p. 299-335
+ */
+
+#include "acos.h"
+#include "atan.h"
+#include "log.h"
+#include "log1p.h"
+#include "sqrt.h"
+#include "abs.h"
+#include "lapack.h"
+#include "min.h"
+#include "max.h"
+
+#define localSign(x) (x>0 ? 1.0f : -1.0f)
+
+floatComplex cacoss(floatComplex z) {
+ static float sfltPi = 3.1415926535897932384626433f;
+ static float sfltPi_2 = 1.5707963267948966192313216f;
+ static float sfltLn2 = 0.6931471805599453094172321f;
+ static float sfltAcross = 1.5f;
+ static float sfltBcross = 0.6417f;
+
+ float fltLsup = ssqrts((float) getOverflowThreshold())/8.0f;
+ float fltLinf = 4.0f * ssqrts((float) getUnderflowThreshold());
+ float fltEpsm = ssqrts((float) getRelativeMachinePrecision());
+
+ float fltAbsReal = sabss(creals(z));
+ float fltAbsImg = sabss(cimags(z));
+ float fltSignReal = localSign(creals(z));
+ float fltSignImg = localSign(cimags(z));
+
+ float fltR = 0, fltS = 0, fltA = 0, fltB = 0;
+
+ float fltTemp = 0;
+
+ float _pfltReal = 0;
+ float _pfltImg = 0;
+
+ if( min(fltAbsReal, fltAbsImg) > fltLinf && max(fltAbsReal, fltAbsImg) <= fltLsup)
+ {/* we are in the safe region */
+ fltR = ssqrts( (fltAbsReal + 1 )*(fltAbsReal + 1 ) + fltAbsImg*fltAbsImg);
+ fltS = ssqrts( (fltAbsReal - 1 )*(fltAbsReal - 1 ) + fltAbsImg*fltAbsImg);
+ fltA = 0.5f * ( fltR + fltS );
+ fltB = fltAbsReal / fltA;
+
+
+ /* compute the real part */
+ if(fltB <= sfltBcross)
+ _pfltReal = sacoss(fltB);
+ else if( fltAbsReal <= 1)
+ _pfltReal = satans(ssqrts(0.5f * (fltA + fltAbsReal) * (fltAbsImg*fltAbsImg / (fltR + (fltAbsReal + 1)) + (fltS + (1 - fltAbsReal)))) / fltAbsReal);
+ else
+ _pfltReal = satans((fltAbsImg * ssqrts(0.5f * ((fltA + fltAbsReal) / (fltR + (fltAbsReal + 1)) + (fltA + fltAbsReal) / (fltS + (fltAbsReal - 1))))) / fltAbsReal);
+
+ /* compute the imaginary part */
+ if(fltA <= sfltAcross)
+ {
+ float fltImg1 = 0;
+
+ if(fltAbsReal < 1)
+ /* Am1 = 0.5d0*((y**2)/(R+(x+1.d0))+(y**2)/(S+(1.d0-x))) */
+ fltImg1 = 0.5f * (fltAbsImg*fltAbsImg / (fltR + (fltAbsReal + 1)) + fltAbsImg*fltAbsImg / (fltS + (1 - fltAbsReal)));
+ else
+ /* Am1 = 0.5d0*((y**2)/(R+(x+1.d0))+(S+(x-1.d0))) */
+ fltImg1 = 0.5f * (fltAbsImg*fltAbsImg / (fltR + (fltAbsReal + 1)) + (fltS + (fltAbsReal - 1)));
+ /* ai = logp1(Am1 + sqrt(Am1*(A+1.d0))) */
+ fltTemp = fltImg1 + ssqrts(fltImg1 *( fltA + 1));
+ _pfltImg = slog1ps(fltTemp);
+ }
+ else
+ /* ai = log(A + sqrt(A**2 - 1.d0)) */
+ _pfltImg = slogs(fltA + ssqrts(fltA*fltA - 1));
+ }
+ else
+ {/* evaluation in the special regions ... */
+ if(fltAbsImg <= fltEpsm * sabss(fltAbsReal - 1))
+ {
+ if(fltAbsReal < 1)
+ {
+ _pfltReal = sacoss(fltAbsReal);
+ _pfltImg = fltAbsImg / ssqrts((1 + fltAbsReal) * (1 - fltAbsReal));
+ }
+ else
+ {
+ _pfltReal = 0;
+ if(fltAbsReal <= fltLsup)
+ {
+ fltTemp = (fltAbsReal - 1) + ssqrts((fltAbsReal - 1) * (fltAbsReal + 1));
+ _pfltImg = slog1ps(fltTemp);
+ }
+ else
+ _pfltImg = sfltLn2 + slogs(fltAbsReal);
+ }
+ }
+ else if(fltAbsImg < fltLinf)
+ {
+ _pfltReal = ssqrts(fltAbsImg);
+ _pfltImg = _pfltReal;
+ }
+ else if((fltEpsm * fltAbsImg - 1 >= fltAbsReal))
+ {
+ _pfltReal = sfltPi_2;
+ _pfltImg = sfltLn2 + slogs(fltAbsImg);
+ }
+ else if(fltAbsReal > 1)
+ {
+ _pfltReal = satans(fltAbsImg / fltAbsReal);
+ fltTemp = (fltAbsReal / fltAbsImg)*(fltAbsReal / fltAbsImg);
+ _pfltImg = sfltLn2 + slogs(fltAbsImg) + 0.5f * slog1ps(fltTemp);
+ }
+ else
+ {
+ float fltTemp2 = ssqrts(1 + fltAbsImg*fltAbsImg);
+ _pfltReal = sfltPi_2;
+ fltTemp = 2 * fltAbsImg * (fltAbsImg + fltTemp2);
+ _pfltImg = 0.5f * slog1ps(fltTemp);
+ }
+ }
+ if(fltSignReal < 0)
+ _pfltReal = sfltPi - _pfltReal;
+
+ if(fltAbsImg != 0 || fltSignReal < 0)
+ _pfltImg = - fltSignImg * _pfltImg;
+
+ return FloatComplex(_pfltReal, _pfltImg);
+}
--
cgit