From 7517890d033b4a3f6c92aa58a62a60d53b1f4814 Mon Sep 17 00:00:00 2001
From: Jeff Hill <johill@lanl.gov>
Date: Tue, 10 Feb 2004 21:43:17 +0000
Subject: [PATCH] installed

---
 src/libCom/math/epicsDSP.h         | 42 ++++++++++++++++
 src/libCom/math/epicsFFT.cpp       | 31 ++++++++++++
 src/libCom/math/epicsTemplateFFT.h | 78 ++++++++++++++++++++++++++++++
 3 files changed, 151 insertions(+)
 create mode 100644 src/libCom/math/epicsDSP.h
 create mode 100644 src/libCom/math/epicsFFT.cpp
 create mode 100644 src/libCom/math/epicsTemplateFFT.h

diff --git a/src/libCom/math/epicsDSP.h b/src/libCom/math/epicsDSP.h
new file mode 100644
index 000000000..f22ba80a6
--- /dev/null
+++ b/src/libCom/math/epicsDSP.h
@@ -0,0 +1,42 @@
+/*************************************************************************\
+* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
+*     National Laboratory.
+* Copyright (c) 2002 The Regents of the University of California, as
+*     Operator of Los Alamos National Laboratory.
+* Subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution. 
+\*************************************************************************/
+
+/*
+ *      Author: Jeff Hill
+ *      Date:   9-29-03
+ */
+
+#ifndef epicsDSP_h
+#define epicsDSP_h
+
+#ifdef __cplusplus
+
+#if !defined ( __GNUC__ ) || ( __GNUC__ > 2 || ( __GNUC__ == 2 && __GNUC_MINOR__ >= 95 ) )
+    namespace std {
+        template < class T > class complex;
+    }
+#else
+    template < class T > class complex;
+#endif
+
+//
+// One dimensional FFT computing template function
+//
+// vec[]    Input Sequence replaced by output sequence
+// ln       Log base two of the number of point in vec
+// inverse  Inverse fft if true
+//
+template < class T >
+void epicsOneDimFFT ( std::complex < T > vec[], 
+        const unsigned ln, bool inverse );
+
+#endif /* __cplusplus */
+
+#endif /* epicsDSP_h */
+
diff --git a/src/libCom/math/epicsFFT.cpp b/src/libCom/math/epicsFFT.cpp
new file mode 100644
index 000000000..ed011cbea
--- /dev/null
+++ b/src/libCom/math/epicsFFT.cpp
@@ -0,0 +1,31 @@
+
+/*************************************************************************\
+* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
+*     National Laboratory.
+* Copyright (c) 2002 The Regents of the University of California, as
+*     Operator of Los Alamos National Laboratory.
+* Subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution. 
+\*************************************************************************/
+
+//
+//      Simple fft computing functions
+//
+//      Author: Jeff Hill
+//      Date:            9-29-03
+//
+
+#include <complex>
+
+#define epicsExportSharedSymbols
+#include <shareLib.h>
+#include <epicsTemplateFFT.h>
+
+// template epicsShareFunc void epicsShareAPI epicsOneDimFFT ( 
+//     std::complex < float > vec[], 
+//     const unsigned ln, bool inverse );
+
+template epicsShareFunc void epicsShareAPI epicsOneDimFFT ( 
+    std::complex < double > vec[], 
+    const unsigned ln, bool inverse );
+        
diff --git a/src/libCom/math/epicsTemplateFFT.h b/src/libCom/math/epicsTemplateFFT.h
new file mode 100644
index 000000000..f1048d12c
--- /dev/null
+++ b/src/libCom/math/epicsTemplateFFT.h
@@ -0,0 +1,78 @@
+/*************************************************************************\
+* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
+*     National Laboratory.
+* Copyright (c) 2002 The Regents of the University of California, as
+*     Operator of Los Alamos National Laboratory.
+* Subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution. 
+\*************************************************************************/
+
+//
+//      Author: Jeff Hill
+//      Date:   9-29-03
+//
+
+#ifndef epicsTemplateFFT_h
+#define epicsTemplateFFT_h
+
+#include <complex>
+
+#include <epicsDSP.h>
+
+//
+// Simple one dimensional FFT computing template function
+//
+// vec[]    Input Sequence replaced by output sequence
+// ln       Log base two of the number of point in vec
+// inverse  Inverse fft if true
+//
+template < class T >
+void epicsOneDimFFT ( std::complex < T > vec[], 
+        const unsigned ln, bool inverse )
+{ 
+    static const T  one = 1.0;
+    static const T  four = 4.0;
+    static const T  PI = four * atan ( one );
+    const unsigned n = 1u << ln;
+    const unsigned nv2 = n >> 1u;
+    
+    {
+        unsigned j = 1u;
+    
+        for ( unsigned i = 1; i < n; i++ ) {
+            if ( i < j ) {
+                std::complex < T > t = vec[i - 1];
+                vec[i - 1] = vec[j - 1];
+                vec[j - 1] = t;
+            }
+            unsigned k = nv2;
+            while ( k < j ) {
+              j = j - k;
+              k = k >> 1u;
+            }
+            j = j + k;
+        }
+    }
+
+    const T sign = inverse ? 1.0 : -1.0;
+    for ( unsigned l = 1; l <= ln; l++ ) {
+        const unsigned le = 1u << l;
+        const unsigned le1 = le >> 1u;
+        const T radians = sign * PI / le1;
+        const std::complex < T > w = std::polar ( one, radians );
+        std::complex < T > u ( 1, 0 );
+        
+        for ( unsigned m = 1u; m <= le1; m++ ) {
+            for ( unsigned i = m - 1; i < n; i = i + le ) {
+                unsigned ip = i + le1;
+                std::complex < T > t0 = vec [ ip ] * u;
+                vec [ ip ] = vec [ i ] - t0;
+                vec [ i  ] = vec [ i ] + t0;
+            }
+            u = u * w;
+        }
+    }
+}
+
+#endif // epicsTemplateFFT_h
+