1 files changed, 92 insertions, 0 deletions
diff --git a/gr-trellis/src/lib/trellis_calc_metric.cc b/gr-trellis/src/lib/trellis_calc_metric.cc
new file mode 100644
index 000000000..c6d2ce98c
--- /dev/null
+++ b/gr-trellis/src/lib/trellis_calc_metric.cc
@@ -0,0 +1,92 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <float.h>
+#include <stdexcept>
+#include "trellis_calc_metric.h"
+
+// soft decisions (Eucledean distance squared)
+void calc_metric_f(const int O, const int D, const std::vector<float> &TABLE, const float *in, float *metric, trellis_metric_type_t type)
+{
+  float minm = FLT_MAX;
+  int minmi = 0;
+
+  switch (type){
+  case TRELLIS_EUCLIDEAN:
+    for(int o=0;o<O;o++) {
+       metric[o]=0.0;
+       for (int m=0;m<D;m++) {
+           float s=in[m]-TABLE[o*D+m];
+           metric[o]+=s*s;
+       }
+    } 
+    break;
+  case TRELLIS_HARD_SYMBOL:
+    for(int o=0;o<O;o++) {
+       metric[o]=0.0;
+       for (int m=0;m<D;m++) {
+           float s=in[m]-TABLE[o*D+m];
+           metric[o]+=s*s;
+       }
+       if(metric[o]<minm) {
+         minm=metric[o];
+         minmi=o;
+       }
+    }
+    for(int o=0;o<O;o++) {
+      metric[o] = (o==minmi?0.0:1.0);
+    }
+    break;
+  case TRELLIS_HARD_BIT:
+    throw std::runtime_error ("Invalid metric type (not yet implemented).");
+    break;
+  default:
+    throw std::runtime_error ("Invalid metric type.");
+  }
+}
+
+
+// soft decisions (Eucledean distance squared)
+void calc_metric_c(const int O, const int D, const std::vector<gr_complex> &TABLE, const gr_complex *in, float *metric, trellis_metric_type_t type)
+{
+  float minm = FLT_MAX;
+  int minmi = 0;
+
+  switch (type){
+  case TRELLIS_EUCLIDEAN:
+    for(int o=0;o<O;o++) {
+      metric[o]=0.0;
+      for (int m=0;m<D;m++) {
+        gr_complex s=in[m]-TABLE[o*D+m];
+        metric[o]+=s.real()*s.real()+s.imag()*s.imag();
+      }
+    }
+  case TRELLIS_HARD_SYMBOL:
+    throw std::runtime_error ("Invalid metric type (not yet implemented).");
+    break;
+  case TRELLIS_HARD_BIT:
+    throw std::runtime_error ("Invalid metric type (not yet implemented).");
+    break;
+  default:
+    throw std::runtime_error ("Invalid metric type.");
+  }
+}