From 334bb67208c1fe2c7b0e4bb26c49eb84f6d79b44 Mon Sep 17 00:00:00 2001
From: Steven Franke <s.j.franke@icloud.com>
Date: Sat, 23 Apr 2016 17:33:13 +0000
Subject: [PATCH] Update to likelihood ratio dither approach.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6635 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
---
 lib/ldpc/dec.c            | 8 ++++----
 lib/ldpc/peg/DenEvl_9.deg | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/ldpc/dec.c b/lib/ldpc/dec.c
index 7f8faa250..86e97ae72 100755
--- a/lib/ldpc/dec.c
+++ b/lib/ldpc/dec.c
@@ -395,11 +395,11 @@ void ldpc_decode_ ( double lratio[], char decoded[], int *max_iterations, int *n
   for (itry=0; itry< *max_dither; itry++) {
     for (i=0; i<N; i++) {
        if( itry == 0 ) {
-         fac=1.0;
+         fac=0.0;
        } else { 
-         fac=1.0+0.8*(rand()%1024-512)/512.0;
-       }
-       lr[i]=lratio[i]*fac;
+         fac=(rand()%1024-512)/512.0;
+       } 
+       lr[i]=lratio[i]*exp(fac); 
     }
     *niterations = prprp_decode ( H, lr, dblk, pchk, bprb );
     valid = check( H, dblk, pchk )==0;
diff --git a/lib/ldpc/peg/DenEvl_9.deg b/lib/ldpc/peg/DenEvl_9.deg
index edc911ab6..3072b205e 100644
--- a/lib/ldpc/peg/DenEvl_9.deg
+++ b/lib/ldpc/peg/DenEvl_9.deg
@@ -1,3 +1,3 @@
 3
-   2           2          9
+   2           3          9
 0.491281    0.335305    0.173414