From 8b44229ef44f0558ce045e46ff833fb44df913c9 Mon Sep 17 00:00:00 2001
From: jofret
Date: Mon, 21 Jun 2010 06:24:38 +0000
Subject: Tagging the 2.0 release of scilab2c

---
 src/c/signalProcessing/ifft/ifft842.c | 163 ++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 src/c/signalProcessing/ifft/ifft842.c

(limited to 'src/c/signalProcessing/ifft/ifft842.c')

diff --git a/src/c/signalProcessing/ifft/ifft842.c b/src/c/signalProcessing/ifft/ifft842.c
new file mode 100644
index 00000000..75f6e1ca
--- /dev/null
+++ b/src/c/signalProcessing/ifft/ifft842.c
@@ -0,0 +1,163 @@
+/*
+ * Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+ * Copyright (C) 2008 - INRIA - Allan SIMON
+ *
+ * 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 "ifft_internal.h"
+
+
+
+/* get binary log of integer argument; exact if n a power of 2 */
+static int fastlog2( int n)
+{
+  int log = -1;
+  while(n) {
+    log++;
+    n >>= 1;
+  }
+  return(log);
+}
+
+/*
+     int in;  FORWARD or INVERSE
+     int n;   length of vector
+     DPCOMPLEX *b;  input vector
+*/
+void ifft842 (doubleComplex* b, int size , int in)
+{
+  double fn;
+  doubleComplex temp ;
+
+  int L[16],L1,L2,L3,L4,L5,L6,L7,L8,L9,L10,L11,L12,L13,L14,L15;
+  int j1,j2,j3,j4,j5,j6,j7,j8,j9,j10,j11,j12,j13,j14;
+  int i = 0, j, ij, ji, ij1, ji1;
+  int  n2pow, n8pow, nthpo, ipass, nxtlt, lengt;
+
+  n2pow = fastlog2( size );
+  nthpo = size ;
+  fn = nthpo;
+
+
+  if(in==INVERSE)
+    /*scramble inputs*/
+
+    for(i=0,j=size/2;j<size;i++,j++)
+      {
+        temp = DoubleComplex ( zreals ( b[j] ) , zimags( b[j] ));
+        b[j] = DoubleComplex ( zreals ( b[i] ) , zimags( b[i] ));
+        b[i] = DoubleComplex ( zreals ( temp ) , zimags( temp ));
+
+        /*
+        r = b[j].re; fi = b[j].im;
+        b[j].re = b[i].re; b[j].im = b[i].im;
+        b[i].re = r; b[i].im = fi;
+        */
+      }
+
+  n8pow = n2pow/3;
+
+  if(n8pow)
+    {
+      /* radix 8 iterations */
+      for(ipass=1;ipass<=n8pow;ipass++)
+	{
+	  nxtlt = 0x1 << (n2pow - 3*ipass);
+	  lengt = 8*nxtlt;
+
+
+
+	  	  ir8tx(nxtlt,nthpo,lengt,
+	       b,b+nxtlt,b+2*nxtlt,
+	       b+3*nxtlt,b+4*nxtlt,b+5*nxtlt,
+	       b+6*nxtlt,b+7*nxtlt);
+
+
+	}
+    }
+
+  if(n2pow%3 == 1)
+    {
+      /* radix 2 iteration needed */
+	ir2tx(nthpo,b,b+1);
+
+
+    }
+
+
+  if(n2pow%3 == 2)
+    {
+      /* radix 4 iteration needed */
+
+      ir4tx(nthpo,b,b+1,b+2,b+3);
+    }
+
+
+
+  for(j=1;j<=15;j++)
+    {
+      L[j] = 1;
+      if(j-n2pow <= 0) L[j] = 0x1 << (n2pow + 1 - j);
+    }
+  L15=L[1];L14=L[2];L13=L[3];L12=L[4];L11=L[5];L10=L[6];L9=L[7];
+  L8=L[8];L7=L[9];L6=L[10];L5=L[11];L4=L[12];L3=L[13];L2=L[14];L1=L[15];
+
+  ij = 1;
+
+
+  for(j1=1;j1<=L1;j1++)
+  for(j2=j1;j2<=L2;j2+=L1)
+  for(j3=j2;j3<=L3;j3+=L2)
+  for(j4=j3;j4<=L4;j4+=L3)
+  for(j5=j4;j5<=L5;j5+=L4)
+  for(j6=j5;j6<=L6;j6+=L5)
+  for(j7=j6;j7<=L7;j7+=L6)
+  for(j8=j7;j8<=L8;j8+=L7)
+  for(j9=j8;j9<=L9;j9+=L8)
+  for(j10=j9;j10<=L10;j10+=L9)
+  for(j11=j10;j11<=L11;j11+=L10)
+  for(j12=j11;j12<=L12;j12+=L11)
+  for(j13=j12;j13<=L13;j13+=L12)
+  for(j14=j13;j14<=L14;j14+=L13)
+  for(ji=j14;ji<=L15;ji+=L14)
+
+    {
+      ij1 = ij-1;
+      ji1 = ji-1;
+
+      if(ij-ji<0)
+	{
+	  temp   = b[ij1];
+	  b[ij1] = b[ji1];
+	  b[ji1] = temp;
+
+	/*
+	  r = b[ij1].re;
+	  b[ij1].re = b[ji1].re;
+	  b[ji1].re = r;
+	  fi = b[ij1].im;
+	  b[ij1].im = b[ji1].im;
+	  b[ji1].im = fi;
+	*/
+	}
+      ij++;
+    }
+
+
+
+  if(in==INVERSE) /* scale outputs */
+    {
+        for(i=0;i<nthpo;i++)
+          {
+            b[i] =  DoubleComplex ( zreals( b[i] )/fn , zimags(b[i])/fn);
+            fn *= -1 ;
+          }
+    }
+
+}
-- 
cgit