Merge in recent ldpc decoder interface updates.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6627 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/ldpc/dec.c

@@ -25,7 +25,7 @@
 #include "mod2sparse.h"
 #include "mod2dense.h"
 #include "mod2convert.h"
-#include "rand.h"
+/*#include "rand.h"*/
 #include "rcode.h"
 #include "check.h"
 #include "dec.h"
@@ -384,23 +384,36 @@ void iterprp
   }
 }
 
-void ldpc_decode_ ( double lratio[], char decoded[], int *max_iterations, int *niterations)
+void ldpc_decode_ ( double lratio[], char decoded[], int *max_iterations, int *niterations, int *max_dither, int *ndither)
 {
-  int i, j, valid;
+  int i, j, itry, valid;
   char dblk[N],pchk[M];
-  double bprb[N];
+  double bprb[N],lr[N];
-    
+  float fac;
+  
   max_iter=*max_iterations;
-  *niterations = prprp_decode ( H, lratio, dblk, pchk, bprb );
+  for (itry=0; itry< *max_dither; itry++) {
-  valid = check( H, dblk, pchk )==0;
+    for (i=0; i<N; i++) {
-  if( !valid ) {
+       if( itry == 0 ) {
-      *niterations=-1;
+         fac=1.0;
-  };
+       } else { 
-
+         fac=1.0+0.8*(rand()%1024-512)/512.0;
-  j=0;
+       }
-  for( i=M; i<N; i++ ) {
+       lr[i]=lratio[i]*fac;
-    decoded[j]=dblk[cols[i]];
+    }
-    j=j+1;
+    *niterations = prprp_decode ( H, lr, dblk, pchk, bprb );
+    valid = check( H, dblk, pchk )==0;
+    if( !valid ) {
+       *niterations=-1;
+    } else {
+      j=0;
+      for( i=M; i<N; i++ ) {
+        decoded[j]=dblk[cols[i]];
+        j=j+1;
+      }
+      *ndither=itry;
+//      printf("ldpc_decode %d %d \n",*niterations, *ndither);
+      return;
+    }
   }
-
 } 

lib/ldpc/enc.c

@@ -17,7 +17,7 @@
 #include <stdlib.h>
 #include <math.h>
 
-#include "rand.h"
+/*#include "rand.h"*/
 #include "alloc.h"
 #include "mod2sparse.h"
 #include "mod2dense.h"

lib/ldpc/enc.h

@@ -16,3 +16,4 @@
 void sparse_encode (char *, char *);
 void dense_encode  (char *, char *, mod2dense *, mod2dense *);
 void mixed_encode  (char *, char *, mod2dense *, mod2dense *);
+void ldpc_encode_  (char *, char *);

lib/ldpc/jtmode_codes/198-72-peg-irreg-8x3-2x4.results

@@ -1,15 +1,15 @@
-peg (198,72), irregular, 80% 3, 20% 4, s=0.75, 50 iterations
+peg (198,72), irregular, 80% 3, 20% 4, s=0.75, 50 iterations; max_dither=200, out of 10000
  Eb/N0   ngood    nundetected
--0.5    35222        2
+-0.5    35222        2   815 0
- 0.0    97638        3
+ 0.0    97638        3  1899 0
- 0.5   220445        4
+ 0.5   220445        4  3824 0
- 1.0   415823        1
+ 1.0   415823        1  5980 0
- 1.5   642153        2
+ 1.5   642153        2  8056 0
- 2.0   832670        0
+ 2.0   832670        0  9283 0
- 2.5   942661        0
+ 2.5   942661        0  9832 0
- 3.0   986548        0
+ 3.0   986548        0  9966 0
- 3.5   997810        0
+ 3.5   997810        0  9996 0
- 4.0   999759        0
+ 4.0   999759        0 10000 0
- 4.5   999980        0
+ 4.5   999980        0 
- 5.0   999997        0
+ 5.0   999997        0 
 

lib/ldpc/jtmode_codes/198-72-peg-reg3.results

@@ -1,14 +1,14 @@
-(198,72) peg, regular, j=3, 50 iterations, s=0.75
+(198,72) peg, regular, j=3, 50 iterations, s=0.75; max_dither=200 (out of 1000)
  Eb/N0   ngood    nundetected
--0.5    50475       26 
+-0.5    50475       26          105000
- 0.0   128150       15
+ 0.0   128150       15          237000
- 0.5   271242       16
+ 0.5   271242       16          430000
- 1.0   477112       18
+ 1.0   477112       18          636000
- 1.5   694045       14
+ 1.5   694045       14          847000
- 2.0   864410        4
+ 2.0   864410        4          943000
- 2.5   955647        1
+ 2.5   955647        1          988000
- 3.0   989346        0
+ 3.0   989346        0         1000000
- 3.5   998132        0
+ 3.5   998132        0         
  4.0   999764        0
  4.5   999968        0
  5.0   999998        0

lib/ldpc/jtmode_codes/fig_compare.gnuplot

@@ -20,7 +20,5 @@ plot [-1:6] [1e-6:1] \
    "198-72-peg-reg4.results" using 1:($3/1000000) with linespoints lt 2 lw 2 pt 2, \
    "198-72-peg-irreg-8x3-2x4.results" using 1:(1-$2/1000000) with linespoints lt 3 lw 2 pt 3, \
    "198-72-peg-irreg-8x3-2x4.results" using 1:($3/1000000) with linespoints lt 3 lw 2 pt 3, \
-   "198-72-sf9.results" using 1:(1-$2/1000000) with linespoints lt 4 lw 2 pt 4, \
-   "198-72-sf9.results" using 1:($3/1000000) with linespoints lt 4 lw 2 pt 4, \
    "compare.lab" with labels
 exit

lib/ldpc/jtmode_codes/fig_success.gnuplot

@@ -14,9 +14,9 @@ set grid
 #set logscale y
 set format y "%2.1f"
 plot [-1:6] [1e-6:1] \
-   "198-72-peg-reg3.results" using 1:($2/1000000) with linespoints lt 1 lw 2 pt 1, \
+   "198-72-peg-irreg-8x3-2x4.results" using 1:($2/1000000) with linespoints lt 1 lw 2 pt 1, \
-   "198-72-peg-reg4.results" using 1:($2/1000000) with linespoints lt 2 lw 2 pt 2, \
+   "198-72-peg-irreg-8x3-2x4.results" using 1:($4/10000) with linespoints lt 2 lw 2 pt 2, \
-   "198-72-peg-irreg-8x3-2x4.results" using 1:($2/1000000) with linespoints lt 3 lw 2 pt 3, \
+   "128-80-peg-reg4.results" using 1:($2/1000000) with linespoints lt 3 lw 2 pt 3, \
-   "198-72-sf9.results" using 1:($2/1000000) with linespoints lt 4 lw 2 pt 4, \
+   "128-80-peg-reg4.results" using 1:($4/1000) with linespoints lt 4 lw 2 pt 4, \
    "success.lab" with labels
 exit

lib/ldpc/jtmode_codes/success.lab

@@ -1,2 +1,2 @@
-0.9 0.75  "(198,72) reg3"
+0.9 0.75  "(198,72)"
-2.9 0.65  "(198,72) reg4" 
+3.5 0.75  "(128,80)" 

lib/ldpc/ldpcsim.f90

@@ -4,14 +4,14 @@ use, intrinsic :: iso_c_binding
 
 ! To change to a new code, edit the following line and the filenames
 ! that contain the parity check and generator matrices.
-parameter (N=198, M=126, K=72) ! M and N are global variables on the C side.
+parameter (N=128, M=48, K=80) ! M and N are global variables on the C side.
 
-character(50) pchk_file,gen_file
+character(80) pchk_file,gen_file
 integer(1) codeword(1:N), decoded(1:K), message(1:K)
 real*8 lratio(N), rxdata(N)
 
-pchk_file="./jtmode_codes/peg-198-72-reg4.pchk"
+pchk_file="./jtmode_codes/peg-128-80-reg4.pchk"
-gen_file="./jtmode_codes/peg-198-72-reg4.gen"
+gen_file="./jtmode_codes/peg-128-80-reg4.gen"
 
 rate=real(K)/real(N)
 
@@ -21,8 +21,9 @@ message(1:K/2)=1
 message((K/2+1):K)=0
 call ldpc_encode(message,codeword)
 
-max_iterations=50
+max_iterations=10
-ntrials=1000000
+max_dither=5
+ntrials=10000
 
 write(*,*) "Eb/N0   ngood    nundetected"
 do idb = 0, 11
@@ -51,7 +52,7 @@ do idb = 0, 11
       lratio(i)=exp(2.0*rxdata(i)/(s*s))
     enddo
 
-    call ldpc_decode(lratio, decoded, max_iterations, niterations)
+    call ldpc_decode(lratio, decoded, max_iterations, niterations, max_dither, ndither)
 
     if( niterations .ge. 0 ) then
       nueflag=0