1 files changed, 64 insertions, 0 deletions
diff --git a/src/signalProcessing/ifft/r4tx.c b/src/signalProcessing/ifft/r4tx.c
new file mode 100644
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+++ b/src/signalProcessing/ifft/r4tx.c
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+/*
+ * 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 "fft_internal.h"
+
+
+
+/*
+** radix 4 iteration subroutine
+*/
+void r4tx( int nthpo, doubleComplex* c0, doubleComplex* c1, doubleComplex* c2, doubleComplex* c3)
+{
+  int kk;
+  doubleComplex temp1 , temp2 , temp3 , temp4 ;
+
+  for(kk=0;kk<nthpo;kk+=4)
+    {
+       /* real and imag parts alternate */
+
+
+	temp1 = zadds ( c0[kk] , c2[kk] ) ;
+	temp2 = zdiffs( c0[kk] , c2[kk] ) ;
+	temp3 = zadds ( c1[kk] , c3[kk] ) ;
+	temp4 = zdiffs( c1[kk] , c3[kk] ) ;
+/*
+      r1 = cr0[kk] + cr2[kk];
+      r2 = cr0[kk] - cr2[kk];
+      r3 = cr1[kk] + cr3[kk];
+      r4 = cr1[kk] - cr3[kk];
+
+
+      i1 = ci0[kk] + ci2[kk];
+      i2 = ci0[kk] - ci2[kk];
+      i3 = ci1[kk] + ci3[kk];
+      i4 = ci1[kk] - ci3[kk];
+*/
+	c0[kk] = zadds ( temp1 , temp3 );
+	c1[kk] = zdiffs( temp1 , temp3 );
+
+/*
+      cr0[kk] = r1 + r3;
+      ci0[kk] = i1 + i3;
+      cr1[kk] = r1 - r3;
+      ci1[kk] = i1 - i3;
+*/
+	c2[kk] = DoubleComplex ( zreals ( temp2 ) - zimags( temp4 ) , zimags ( temp2 ) + zreals( temp4 ) );
+	c3[kk] = DoubleComplex ( zreals ( temp2 ) + zimags( temp4 ) , zimags ( temp2 ) - zreals( temp4 ) );
+/*
+      cr2[kk] = r2 - i4;
+      ci2[kk] = i2 + r4;
+      cr3[kk] = r2 + i4;
+      ci3[kk] = i2 - r4;
+*/
+    }
+}