This file specifies the sparse 83x174 parity-check matrix for the 
FT8/FT4 (174,91) LDPC code. Each of the 174 columns contains
exactly 3 ones. The rows contain either 6 or 7 ones.  
The matrix is specified by the following list consisting of 
174 lines, each of which includes 3 numbers. 
Each line corresponds to a column of the parity check matrix. 
The three numbers are indices of the rows that contain a one in
the corresponding column. The indices range from 1 through 83. 
 
  16   45   73
  25   51   62
  33   58   78
   1   44   45
   2    7   61
   3    6   54
   4   35   48
   5   13   21
   8   56   79
   9   64   69
  10   19   66
  11   36   60
  12   37   58
  14   32   43
  15   63   80
  17   28   77
  18   74   83
  22   53   81
  23   30   34
  24   31   40
  26   41   76
  27   57   70
  29   49   65
   3   38   78
   5   39   82
  46   50   73
  51   52   74
  55   71   72
  44   67   72
  43   68   78
   1   32   59
   2    6   71
   4   16   54
   7   65   67
   8   30   42
   9   22   31
  10   18   76
  11   23   82
  12   28   61
  13   52   79
  14   50   51
  15   81   83
  17   29   60
  19   33   64
  20   26   73
  21   34   40
  24   27   77
  25   55   58
  35   53   66
  36   48   68
  37   46   75
  38   45   47
  39   57   69
  41   56   62
  20   49   53
  46   52   63
  45   70   75
  27   35   80
   1   15   30
   2   68   80
   3   36   51
   4   28   51
   5   31   56
   6   20   37
   7   40   82
   8   60   69
   9   10   49
  11   44   57
  12   39   59
  13   24   55
  14   21   65
  16   71   78
  17   30   76
  18   25   80
  19   61   83
  22   38   77
  23   41   50
   7   26   58
  29   32   81
  33   40   73
  18   34   48
  13   42   64
   5   26   43
  47   69   72
  54   55   70
  45   62   68
  10   63   67
  14   66   72
  22   60   74
  35   39   79
   1   46   64
   1   24   66
   2    5   70
   3   31   65
   4   49   58
   1    4    5
   6   60   67
   7   32   75
   8   48   82
   9   35   41
  10   39   62
  11   14   61
  12   71   74
  13   23   78
  11   35   55
  15   16   79
   7    9   16
  17   54   63
  18   50   57
  19   30   47
  20   64   80
  21   28   69
  22   25   43
  13   22   37
   2   47   51
  23   54   74
  26   34   72
  27   36   37
  21   36   63
  29   40   44
  19   26   57
   3   46   82
  14   15   58
  33   52   53
  30   43   52
   6    9   52
  27   33   65
  25   69   73
  38   55   83
  20   39   77
  18   29   56
  32   48   71
  42   51   59
  28   44   79
  34   60   62
  31   45   61
  46   68   77
   6   24   76
   8   10   78
  40   41   70
  17   50   53
  42   66   68
   4   22   72
  36   64   81
  13   29   47
   2    8   81
  56   67   73
   5   38   50
  12   38   64
  59   72   80
   3   26   79
  45   76   81
   1   65   74
   7   18   77
  11   56   59
  14   39   54
  16   37   66
  10   28   55
  15   60   70
  17   25   82
  20   30   31
  12   67   68
  23   75   80
  27   32   62
  24   69   75
  19   21   71
  34   53   61
  35   46   47
  33   59   76
  40   43   83
  41   42   63
  49   75   83
  20   44   48
  42   49   57