WSJT-X/lib/fsk4hf/bpdecode300.f90

709 lines
23 KiB
Fortran

subroutine bpdecode300(llr,apmask,maxiterations,decoded,niterations,cw)
! A log-domain belief propagation decoder for the (300,60) code.
integer, parameter:: N=300, K=60, M=N-K
integer*1 codeword(N),cw(N),apmask(N)
integer colorder(N)
integer*1 decoded(K)
integer Nm(5,M) ! 4, or 5 bits per check
integer Mn(7,N) ! 2, 3, or 7 checks per bit
integer synd(M)
real tov(7,N)
real toc(5,M)
real tanhtoc(5,M)
real zn(N)
real llr(N)
real Tmn
integer nrw(M)
integer ncw(N)
data colorder/ &
0,1,2,3,4,5,6,7,8,9,10,11,123,12,13,14,15,16,17,18, &
19,20,21,22,23,24,25,138,26,145,27,28,29,30,31,32,33,34,35,36, &
37,154,38,39,40,41,42,43,44,144,46,47,48,49,50,51,52,53,143,54, &
125,56,57,58,124,59,120,140,157,160,55,60,61,62,156,162,141,64,65,153, &
181,183,66,170,67,68,69,130,70,164,71,72,73,74,75,63,76,77,135,78, &
79,80,176,169,82,83,84,167,180,85,136,158,129,166,175,142,134,146,121,165, &
88,89,192,90,45,91,92,93,182,189,94,95,96,173,81,97,98,178,122,126, &
132,99,100,152,186,193,101,102,151,103,104,172,159,168,150,190,147,148,201,107, &
205,177,108,198,197,174,127,109,185,110,202,87,199,171,179,187,139,137,106,131, &
206,194,112,149,155,113,128,184,196,86,114,203,212,195,208,105,188,161,163,191, &
200,209,214,204,115,218,133,111,207,117,213,216,211,217,116,215,219,220,210,221, &
118,222,223,225,224,228,226,229,231,227,233,119,234,235,232,230,237,239,236,238, &
240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259, &
260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279, &
280,281,282,283,284,285,286,287,288,289,290,291,292,293,294,295,296,297,298,299/
data Mn/ &
1, 67, 0, 0, 0, 0, 0, &
2, 189, 0, 0, 0, 0, 0, &
3, 201, 0, 0, 0, 0, 0, &
4, 13, 0, 0, 0, 0, 0, &
5, 84, 0, 0, 0, 0, 0, &
6, 188, 0, 0, 0, 0, 0, &
7, 140, 0, 0, 0, 0, 0, &
8, 167, 0, 0, 0, 0, 0, &
9, 187, 0, 0, 0, 0, 0, &
10, 173, 0, 0, 0, 0, 0, &
11, 88, 0, 0, 0, 0, 0, &
12, 213, 0, 0, 0, 0, 0, &
14, 141, 0, 0, 0, 0, 0, &
15, 236, 0, 0, 0, 0, 0, &
16, 117, 0, 0, 0, 0, 0, &
17, 99, 0, 0, 0, 0, 0, &
18, 111, 0, 0, 0, 0, 0, &
19, 178, 0, 0, 0, 0, 0, &
20, 28, 0, 0, 0, 0, 0, &
21, 177, 0, 0, 0, 0, 0, &
22, 199, 0, 0, 0, 0, 0, &
23, 209, 0, 0, 0, 0, 0, &
24, 220, 0, 0, 0, 0, 0, &
25, 59, 0, 0, 0, 0, 0, &
26, 224, 0, 0, 0, 0, 0, &
27, 30, 0, 0, 0, 0, 0, &
29, 157, 0, 0, 0, 0, 0, &
31, 184, 0, 0, 0, 0, 0, &
32, 179, 0, 0, 0, 0, 0, &
33, 149, 0, 0, 0, 0, 0, &
34, 144, 0, 0, 0, 0, 0, &
35, 80, 0, 0, 0, 0, 0, &
36, 228, 0, 0, 0, 0, 0, &
37, 185, 0, 0, 0, 0, 0, &
38, 197, 0, 0, 0, 0, 0, &
39, 69, 0, 0, 0, 0, 0, &
40, 42, 0, 0, 0, 0, 0, &
41, 112, 0, 0, 0, 0, 0, &
43, 70, 0, 0, 0, 0, 0, &
44, 198, 0, 0, 0, 0, 0, &
45, 76, 0, 0, 0, 0, 0, &
46, 68, 0, 0, 0, 0, 0, &
47, 90, 0, 0, 0, 0, 0, &
48, 75, 0, 0, 0, 0, 0, &
49, 118, 0, 0, 0, 0, 0, &
50, 125, 0, 0, 0, 0, 0, &
51, 114, 0, 0, 0, 0, 0, &
52, 239, 0, 0, 0, 0, 0, &
53, 108, 0, 0, 0, 0, 0, &
54, 120, 0, 0, 0, 0, 0, &
55, 162, 0, 0, 0, 0, 0, &
56, 218, 0, 0, 0, 0, 0, &
57, 138, 0, 0, 0, 0, 0, &
58, 212, 0, 0, 0, 0, 0, &
60, 207, 0, 0, 0, 0, 0, &
61, 71, 0, 0, 0, 0, 0, &
62, 65, 0, 0, 0, 0, 0, &
63, 161, 0, 0, 0, 0, 0, &
64, 166, 0, 0, 0, 0, 0, &
66, 158, 0, 0, 0, 0, 0, &
72, 235, 0, 0, 0, 0, 0, &
73, 225, 0, 0, 0, 0, 0, &
74, 116, 0, 0, 0, 0, 0, &
77, 96, 0, 0, 0, 0, 0, &
78, 81, 0, 0, 0, 0, 0, &
79, 82, 0, 0, 0, 0, 0, &
83, 229, 0, 0, 0, 0, 0, &
85, 134, 0, 0, 0, 0, 0, &
86, 176, 0, 0, 0, 0, 0, &
87, 203, 0, 0, 0, 0, 0, &
89, 145, 0, 0, 0, 0, 0, &
91, 152, 0, 0, 0, 0, 0, &
92, 237, 0, 0, 0, 0, 0, &
93, 215, 0, 0, 0, 0, 0, &
94, 130, 0, 0, 0, 0, 0, &
95, 156, 0, 0, 0, 0, 0, &
97, 104, 0, 0, 0, 0, 0, &
98, 182, 0, 0, 0, 0, 0, &
100, 222, 0, 0, 0, 0, 0, &
101, 123, 0, 0, 0, 0, 0, &
102, 181, 0, 0, 0, 0, 0, &
103, 135, 0, 0, 0, 0, 0, &
105, 146, 0, 0, 0, 0, 0, &
106, 115, 0, 0, 0, 0, 0, &
107, 109, 0, 0, 0, 0, 0, &
110, 194, 0, 0, 0, 0, 0, &
113, 164, 0, 0, 0, 0, 0, &
119, 172, 0, 0, 0, 0, 0, &
121, 190, 0, 0, 0, 0, 0, &
122, 169, 0, 0, 0, 0, 0, &
124, 211, 0, 0, 0, 0, 0, &
126, 165, 0, 0, 0, 0, 0, &
127, 139, 0, 0, 0, 0, 0, &
128, 129, 0, 0, 0, 0, 0, &
131, 205, 0, 0, 0, 0, 0, &
132, 196, 0, 0, 0, 0, 0, &
133, 193, 0, 0, 0, 0, 0, &
136, 200, 0, 0, 0, 0, 0, &
137, 159, 0, 0, 0, 0, 0, &
142, 204, 0, 0, 0, 0, 0, &
143, 154, 0, 0, 0, 0, 0, &
147, 238, 0, 0, 0, 0, 0, &
148, 175, 0, 0, 0, 0, 0, &
150, 216, 0, 0, 0, 0, 0, &
151, 171, 0, 0, 0, 0, 0, &
153, 231, 0, 0, 0, 0, 0, &
155, 208, 0, 0, 0, 0, 0, &
160, 230, 0, 0, 0, 0, 0, &
163, 223, 0, 0, 0, 0, 0, &
168, 217, 0, 0, 0, 0, 0, &
170, 180, 0, 0, 0, 0, 0, &
174, 233, 0, 0, 0, 0, 0, &
183, 202, 0, 0, 0, 0, 0, &
186, 214, 0, 0, 0, 0, 0, &
191, 206, 0, 0, 0, 0, 0, &
192, 219, 0, 0, 0, 0, 0, &
195, 227, 0, 0, 0, 0, 0, &
210, 226, 0, 0, 0, 0, 0, &
221, 234, 0, 0, 0, 0, 0, &
232, 240, 0, 0, 0, 0, 0, &
1, 106, 0, 0, 0, 0, 0, &
2, 119, 0, 0, 0, 0, 0, &
3, 139, 0, 0, 0, 0, 0, &
4, 14, 0, 0, 0, 0, 0, &
5, 65, 0, 0, 0, 0, 0, &
6, 61, 0, 0, 0, 0, 0, &
7, 223, 0, 0, 0, 0, 0, &
8, 171, 0, 0, 0, 0, 0, &
9, 136, 0, 0, 0, 0, 0, &
10, 113, 0, 0, 0, 0, 0, &
11, 104, 0, 0, 0, 0, 0, &
12, 175, 0, 0, 0, 0, 0, &
13, 203, 0, 0, 0, 0, 0, &
15, 149, 0, 0, 0, 0, 0, &
16, 226, 0, 0, 0, 0, 0, &
17, 219, 0, 0, 0, 0, 0, &
18, 98, 0, 0, 0, 0, 0, &
19, 211, 0, 0, 0, 0, 0, &
20, 49, 0, 0, 0, 0, 0, &
21, 214, 0, 0, 0, 0, 0, &
22, 68, 0, 0, 0, 0, 0, &
23, 77, 0, 0, 0, 0, 0, &
24, 116, 0, 0, 0, 0, 0, &
25, 235, 0, 0, 0, 0, 0, &
26, 50, 0, 0, 0, 0, 0, &
27, 124, 0, 0, 0, 0, 0, &
28, 229, 0, 0, 0, 0, 0, &
29, 83, 0, 0, 0, 0, 0, &
30, 158, 0, 0, 0, 0, 0, &
31, 220, 0, 0, 0, 0, 0, &
32, 155, 0, 0, 0, 0, 0, &
33, 152, 0, 0, 0, 0, 0, &
34, 231, 0, 0, 0, 0, 0, &
35, 207, 0, 0, 0, 0, 0, &
36, 40, 0, 0, 0, 0, 0, &
37, 142, 0, 0, 0, 0, 0, &
38, 75, 0, 0, 0, 0, 0, &
39, 90, 167, 0, 0, 0, 0, &
41, 55, 125, 0, 0, 0, 0, &
42, 153, 196, 0, 0, 0, 0, &
43, 72, 112, 0, 0, 0, 0, &
44, 183, 233, 0, 0, 0, 0, &
45, 81, 178, 0, 0, 0, 0, &
46, 187, 230, 0, 0, 0, 0, &
47, 133, 176, 0, 0, 0, 0, &
48, 54, 186, 0, 0, 0, 0, &
51, 150, 224, 0, 0, 0, 0, &
52, 53, 190, 0, 0, 0, 0, &
56, 143, 228, 0, 0, 0, 0, &
57, 97, 197, 0, 0, 0, 0, &
58, 62, 89, 0, 0, 0, 0, &
59, 174, 194, 0, 0, 0, 0, &
60, 91, 93, 0, 0, 0, 0, &
63, 85, 96, 0, 0, 0, 0, &
64, 92, 205, 0, 0, 0, 0, &
66, 67, 164, 0, 0, 0, 0, &
69, 103, 159, 0, 0, 0, 0, &
70, 117, 122, 0, 0, 0, 0, &
71, 88, 160, 0, 0, 0, 0, &
73, 148, 180, 0, 0, 0, 0, &
74, 108, 109, 0, 0, 0, 0, &
76, 102, 151, 0, 0, 0, 0, &
78, 128, 206, 0, 0, 0, 0, &
79, 215, 239, 0, 0, 0, 0, &
80, 138, 221, 0, 0, 0, 0, &
82, 162, 195, 0, 0, 0, 0, &
84, 161, 184, 0, 0, 0, 0, &
86, 213, 218, 0, 0, 0, 0, &
87, 120, 240, 0, 0, 0, 0, &
94, 100, 157, 0, 0, 0, 0, &
95, 202, 217, 0, 0, 0, 0, &
99, 199, 201, 0, 0, 0, 0, &
101, 127, 225, 0, 0, 0, 0, &
105, 168, 185, 0, 0, 0, 0, &
107, 182, 237, 0, 0, 0, 0, &
110, 147, 208, 0, 0, 0, 0, &
111, 118, 172, 0, 0, 0, 0, &
114, 140, 165, 0, 0, 0, 0, &
115, 130, 141, 0, 0, 0, 0, &
121, 144, 173, 0, 0, 0, 0, &
123, 204, 209, 0, 0, 0, 0, &
126, 137, 188, 0, 0, 0, 0, &
129, 179, 189, 0, 0, 0, 0, &
131, 192, 210, 0, 0, 0, 0, &
132, 200, 238, 0, 0, 0, 0, &
134, 177, 191, 0, 0, 0, 0, &
135, 145, 222, 0, 0, 0, 0, &
146, 229, 236, 0, 0, 0, 0, &
154, 169, 232, 0, 0, 0, 0, &
124, 156, 163, 0, 0, 0, 0, &
166, 223, 234, 0, 0, 0, 0, &
1, 11, 170, 0, 0, 0, 0, &
3, 181, 227, 0, 0, 0, 0, &
193, 198, 220, 0, 0, 0, 0, &
10, 16, 212, 0, 0, 0, 0, &
42, 96, 216, 0, 0, 0, 0, &
2, 6, 215, 0, 0, 0, 0, &
4, 208, 219, 0, 0, 0, 0, &
5, 22, 35, 0, 0, 0, 0, &
7, 12, 20, 0, 0, 0, 0, &
8, 15, 75, 0, 0, 0, 0, &
9, 74, 83, 0, 0, 0, 0, &
13, 37, 50, 0, 0, 0, 0, &
14, 52, 86, 0, 0, 0, 0, &
17, 30, 177, 0, 0, 0, 0, &
18, 25, 97, 0, 0, 0, 0, &
19, 72, 157, 0, 0, 0, 0, &
21, 58, 116, 0, 0, 0, 0, &
23, 111, 226, 0, 0, 0, 0, &
24, 26, 180, 0, 0, 0, 0, &
27, 34, 39, 0, 0, 0, 0, &
28, 32, 161, 0, 0, 0, 0, &
29, 36, 60, 0, 0, 0, 0, &
31, 76, 154, 0, 0, 0, 0, &
33, 101, 238, 0, 0, 0, 0, &
38, 95, 162, 0, 0, 0, 0, &
40, 164, 183, 0, 0, 0, 0, &
41, 92, 196, 0, 0, 0, 0, &
43, 48, 99, 165, 190, 198, 204, &
44, 129, 138, 145, 160, 203, 237, &
45, 65, 66, 98, 127, 137, 146, &
46, 131, 149, 181, 211, 218, 224, &
47, 49, 55, 191, 194, 207, 232, &
51, 69, 106, 109, 119, 184, 217, &
53, 62, 104, 155, 166, 206, 231, &
54, 61, 63, 73, 118, 151, 163, &
56, 94, 110, 117, 185, 189, 214, &
57, 81, 91, 115, 173, 175, 227, &
59, 79, 103, 136, 171, 201, 212, &
24, 64, 77, 93, 202, 235, 236, &
67, 132, 142, 150, 156, 176, 222, &
68, 153, 159, 169, 170, 186, 221, &
70, 84, 89, 113, 174, 197, 205, &
71, 125, 130, 140, 158, 200, 210, &
8, 78, 143, 182, 192, 193, 216, &
23, 80, 82, 90, 108, 139, 228, &
85, 122, 123, 128, 141, 187, 188, &
25, 87, 100, 152, 209, 213, 234, &
88, 134, 147, 167, 172, 178, 239, &
18, 40, 102, 114, 133, 144, 179, &
4, 105, 108, 112, 148, 230, 240, &
29, 33, 50, 62, 107, 195, 199, &
3, 83, 113, 120, 126, 177, 216, &
11, 55, 116, 121, 135, 168, 225, &
1, 27, 28, 76, 187, 226, 233, &
2, 4, 7, 10, 22, 75, 222, &
5, 30, 131, 152, 156, 168, 215, &
6, 13, 19, 58, 196, 228, 229, &
9, 26, 144, 147, 158, 223, 240, &
12, 31, 66, 79, 92, 96, 155, &
14, 54, 103, 173, 202, 232, 238, &
15, 17, 37, 69, 129, 164, 209, &
16, 72, 91, 114, 163, 169, 237, &
20, 45, 89, 99, 143, 180, 208, &
21, 39, 60, 141, 171, 198, 234, &
21, 32, 52, 78, 95, 148, 199, &
34, 73, 84, 157, 200, 221, 236, &
35, 36, 63, 97, 105, 119, 220, &
38, 46, 93, 111, 136, 191, 203, &
41, 51, 151, 160, 213, 214, 231, &
42, 57, 65, 161, 167, 194, 204, &
43, 109, 162, 175, 189, 210, 212, &
44, 74, 100, 149, 170, 188, 197, &
47, 64, 88, 107, 122, 165, 211, &
48, 139, 179, 184, 218, 233, 239, &
49, 94, 106, 112, 138, 142, 205, &
53, 59, 102, 115, 134, 182, 225, &
56, 68, 101, 150, 166, 178, 207, &
61, 117, 126, 154, 195, 219, 224, &
67, 80, 118, 174, 185, 190, 235, &
70, 77, 86, 125, 153, 172, 193, &
32, 71, 87, 90, 98, 110, 135, &
41, 75, 81, 85, 124, 133, 201, &
82, 120, 128, 140, 159, 176, 183, &
22, 72, 104, 130, 146, 181, 217, &
25, 89, 96, 121, 132, 186, 230, &
118, 123, 145, 192, 196, 227, 240, &
1, 14, 35, 38, 114, 127, 192, &
7, 23, 43, 63, 116, 137, 206, &
2, 37, 52, 57, 64, 76, 120/
data Nm/ &
1, 121, 212, 265, 298, &
2, 122, 217, 266, 300, &
3, 123, 213, 263, 0, &
4, 124, 218, 261, 266, &
5, 125, 219, 267, 0, &
6, 126, 217, 268, 0, &
7, 127, 220, 266, 299, &
8, 128, 221, 255, 0, &
9, 129, 222, 269, 0, &
10, 130, 215, 266, 0, &
11, 131, 212, 264, 0, &
12, 132, 220, 270, 0, &
4, 133, 223, 268, 0, &
13, 124, 224, 271, 298, &
14, 134, 221, 272, 0, &
15, 135, 215, 273, 0, &
16, 136, 225, 272, 0, &
17, 137, 226, 260, 0, &
18, 138, 227, 268, 0, &
19, 139, 220, 274, 0, &
20, 140, 228, 275, 276, &
21, 141, 219, 266, 295, &
22, 142, 229, 256, 299, &
23, 143, 230, 250, 0, &
24, 144, 226, 258, 296, &
25, 145, 230, 269, 0, &
26, 146, 231, 265, 0, &
19, 147, 232, 265, 0, &
27, 148, 233, 262, 0, &
26, 149, 225, 267, 0, &
28, 150, 234, 270, 0, &
29, 151, 232, 276, 292, &
30, 152, 235, 262, 0, &
31, 153, 231, 277, 0, &
32, 154, 219, 278, 298, &
33, 155, 233, 278, 0, &
34, 156, 223, 272, 300, &
35, 157, 236, 279, 298, &
36, 158, 231, 275, 0, &
37, 155, 237, 260, 0, &
38, 159, 238, 280, 293, &
37, 160, 216, 281, 0, &
39, 161, 239, 282, 299, &
40, 162, 240, 283, 0, &
41, 163, 241, 274, 0, &
42, 164, 242, 279, 0, &
43, 165, 243, 284, 0, &
44, 166, 239, 285, 0, &
45, 139, 243, 286, 0, &
46, 145, 223, 262, 0, &
47, 167, 244, 280, 0, &
48, 168, 224, 276, 300, &
49, 168, 245, 287, 0, &
50, 166, 246, 271, 0, &
51, 159, 243, 264, 0, &
52, 169, 247, 288, 0, &
53, 170, 248, 281, 300, &
54, 171, 228, 268, 0, &
24, 172, 249, 287, 0, &
55, 173, 233, 275, 0, &
56, 126, 246, 289, 0, &
57, 171, 245, 262, 0, &
58, 174, 246, 278, 299, &
59, 175, 250, 284, 300, &
57, 125, 241, 281, 0, &
60, 176, 241, 270, 0, &
1, 176, 251, 290, 0, &
42, 141, 252, 288, 0, &
36, 177, 244, 272, 0, &
39, 178, 253, 291, 0, &
56, 179, 254, 292, 0, &
61, 161, 227, 273, 295, &
62, 180, 246, 277, 0, &
63, 181, 222, 283, 0, &
44, 157, 221, 266, 293, &
41, 182, 234, 265, 300, &
64, 142, 250, 291, 0, &
65, 183, 255, 276, 0, &
66, 184, 249, 270, 0, &
32, 185, 256, 290, 0, &
65, 163, 248, 293, 0, &
66, 186, 256, 294, 0, &
67, 148, 222, 263, 0, &
5, 187, 253, 277, 0, &
68, 174, 257, 293, 0, &
69, 188, 224, 291, 0, &
70, 189, 258, 292, 0, &
11, 179, 259, 284, 0, &
71, 171, 253, 274, 296, &
43, 158, 256, 292, 0, &
72, 173, 248, 273, 0, &
73, 175, 238, 270, 0, &
74, 173, 250, 279, 0, &
75, 190, 247, 286, 0, &
76, 191, 236, 276, 0, &
64, 174, 216, 270, 296, &
77, 170, 226, 278, 0, &
78, 137, 241, 292, 0, &
16, 192, 239, 274, 0, &
79, 190, 258, 283, 0, &
80, 193, 235, 288, 0, &
81, 182, 260, 287, 0, &
82, 177, 249, 271, 0, &
77, 131, 245, 295, 0, &
83, 194, 261, 278, 0, &
84, 121, 244, 286, 0, &
85, 195, 262, 284, 0, &
49, 181, 256, 261, 0, &
85, 181, 244, 282, 0, &
86, 196, 247, 292, 0, &
17, 197, 229, 279, 0, &
38, 161, 261, 286, 0, &
87, 130, 253, 263, 0, &
47, 198, 260, 273, 298, &
84, 199, 248, 287, 0, &
63, 143, 228, 264, 299, &
15, 178, 247, 289, 0, &
45, 197, 246, 290, 297, &
88, 122, 244, 278, 0, &
50, 189, 263, 294, 300, &
89, 200, 264, 296, 0, &
90, 178, 257, 284, 0, &
80, 201, 257, 297, 0, &
91, 146, 210, 293, 0, &
46, 159, 254, 291, 0, &
92, 202, 263, 289, 0, &
93, 193, 241, 298, 0, &
94, 183, 257, 294, 0, &
94, 203, 240, 272, 0, &
75, 199, 254, 295, 0, &
95, 204, 242, 267, 0, &
96, 205, 251, 296, 0, &
97, 165, 260, 293, 0, &
68, 206, 259, 287, 0, &
82, 207, 264, 292, 0, &
98, 129, 249, 279, 0, &
99, 202, 241, 299, 0, &
53, 185, 240, 286, 0, &
93, 123, 256, 285, 0, &
7, 198, 254, 294, 0, &
13, 199, 257, 275, 0, &
100, 156, 251, 286, 0, &
101, 169, 255, 274, 0, &
31, 200, 260, 269, 0, &
71, 207, 240, 297, 0, &
83, 208, 241, 295, 0, &
102, 196, 259, 269, 0, &
103, 180, 261, 276, 0, &
30, 134, 242, 283, 0, &
104, 167, 251, 288, 0, &
105, 182, 246, 280, 0, &
72, 152, 258, 267, 0, &
106, 160, 252, 291, 0, &
101, 209, 234, 289, 0, &
107, 151, 245, 270, 0, &
76, 210, 251, 267, 0, &
27, 190, 227, 277, 0, &
60, 149, 254, 269, 0, &
99, 177, 252, 294, 0, &
108, 179, 240, 280, 0, &
58, 187, 232, 281, 0, &
51, 186, 236, 282, 0, &
109, 210, 246, 273, 0, &
87, 176, 237, 272, 0, &
92, 198, 239, 284, 0, &
59, 211, 245, 288, 0, &
8, 158, 259, 281, 0, &
110, 194, 264, 267, 0, &
90, 209, 252, 273, 0, &
111, 212, 252, 283, 0, &
105, 128, 249, 275, 0, &
88, 197, 259, 291, 0, &
10, 200, 248, 271, 0, &
112, 172, 253, 290, 0, &
103, 132, 248, 282, 0, &
69, 165, 251, 294, 0, &
20, 206, 225, 263, 0, &
18, 163, 259, 288, 0, &
29, 203, 260, 285, 0, &
111, 180, 230, 274, 0, &
81, 213, 242, 295, 0, &
78, 195, 255, 287, 0, &
113, 162, 237, 294, 0, &
28, 187, 244, 285, 0, &
34, 194, 247, 290, 0, &
114, 166, 252, 296, 0, &
9, 164, 257, 265, 0, &
6, 202, 257, 283, 0, &
2, 203, 247, 282, 0, &
89, 168, 239, 290, 0, &
115, 206, 243, 279, 0, &
116, 204, 255, 297, 298, &
97, 214, 255, 291, 0, &
86, 172, 243, 281, 0, &
117, 186, 262, 289, 0, &
96, 160, 238, 268, 297, &
35, 170, 253, 283, 0, &
40, 214, 239, 275, 0, &
21, 192, 262, 276, 0, &
98, 205, 254, 277, 0, &
3, 192, 249, 293, 0, &
113, 191, 250, 271, 0, &
70, 133, 240, 279, 0, &
100, 201, 239, 281, 0, &
95, 175, 253, 286, 0, &
115, 183, 245, 299, 0, &
55, 154, 243, 288, 0, &
107, 196, 218, 274, 0, &
22, 201, 258, 272, 0, &
118, 204, 254, 282, 0, &
91, 138, 242, 284, 0, &
54, 215, 249, 282, 0, &
12, 188, 258, 280, 0, &
114, 140, 247, 280, 0, &
74, 184, 217, 267, 0, &
104, 216, 255, 263, 0, &
110, 191, 244, 295, 0, &
52, 188, 242, 285, 0, &
116, 136, 218, 289, 0, &
23, 150, 214, 278, 0, &
119, 185, 252, 277, 0, &
79, 207, 251, 266, 0, &
109, 127, 211, 269, 0, &
25, 167, 242, 289, 0, &
62, 193, 264, 287, 0, &
118, 135, 229, 265, 0, &
117, 213, 248, 297, 0, &
33, 169, 256, 268, 0, &
67, 147, 208, 268, 0, &
108, 164, 261, 296, 0, &
106, 153, 245, 280, 0, &
120, 209, 243, 271, 0, &
112, 162, 265, 285, 0, &
119, 211, 258, 275, 0, &
61, 144, 250, 290, 0, &
14, 208, 250, 277, 0, &
73, 195, 240, 273, 0, &
102, 205, 235, 271, 0, &
48, 184, 259, 285, 0, &
120, 189, 261, 269, 297/
data nrw/ &
5,5,4,5,4,4,5,4,4,4,4,4,4,5,4,4,4,4,4,4, &
5,5,5,4,5,4,4,4,4,4,4,5,4,4,5,4,5,5,4,4, &
5,4,5,4,4,4,4,4,4,4,4,5,4,4,4,4,5,4,4,4, &
4,4,5,5,4,4,4,4,4,4,4,5,4,4,5,5,4,4,4,4, &
4,4,4,4,4,4,4,4,5,4,4,4,4,4,4,5,4,4,4,4, &
4,4,4,4,4,4,4,4,4,4,4,4,4,5,4,5,4,5,4,5, &
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, &
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, &
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, &
4,4,4,4,4,4,4,4,4,4,4,5,4,4,4,5,4,4,4,4, &
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, &
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,5/
data ncw/ &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, &
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3, &
3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, &
3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, &
3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, &
3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,7,7, &
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, &
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, &
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7/
!ncw=3
toc=0
tov=0
tanhtoc=0
!write(*,*) llr
! initialize messages to checks
do j=1,M
do i=1,nrw(j)
toc(i,j)=llr((Nm(i,j)))
enddo
enddo
ncnt=0
do iter=0,maxiterations
! Update bit log likelihood ratios (tov=0 in iteration 0).
do i=1,N
if( apmask(i) .ne. 1 ) then
zn(i)=llr(i)+sum(tov(1:ncw(i),i))
else
zn(i)=llr(i)
endif
enddo
! Check to see if we have a codeword (check before we do any iteration).
cw=0
where( zn .gt. 0. ) cw=1
ncheck=0
do i=1,M
synd(i)=sum(cw(Nm(1:nrw(i),i)))
if( mod(synd(i),2) .ne. 0 ) ncheck=ncheck+1
! if( mod(synd(i),2) .ne. 0 ) write(*,*) 'check ',i,' unsatisfied'
enddo
!write(*,*) 'number of unsatisfied parity checks ',ncheck
if( ncheck .eq. 0 ) then ! we have a codeword - reorder the columns and return it
! niterations=iter
codeword=cw(colorder+1)
decoded=codeword(M+1:N)
nerr=0
do i=1,N
if( (2*cw(i)-1)*llr(i) .lt. 0.0 ) nerr=nerr+1
enddo
niterations=nerr
return
endif
if( iter.gt.0 ) then ! this code block implements an early stopping criterion
nd=ncheck-nclast
if( nd .lt. 0 ) then ! # of unsatisfied parity checks decreased
ncnt=0 ! reset counter
else
ncnt=ncnt+1
endif
! write(*,*) iter,ncheck,nd,ncnt
if( ncnt .ge. 5 .and. iter .ge. 15 .and. ncheck .gt. 50) then
niterations=-1
return
endif
endif
nclast=ncheck
! Send messages from bits to check nodes
do j=1,M
do i=1,nrw(j)
ibj=Nm(i,j)
toc(i,j)=zn(ibj)
! do kk=1,ncw(ibj) ! subtract off what the bit had received from the check
do kk=1,7 ! subtract off what the bit had received from the check
if( Mn(kk,ibj) .eq. j ) then
toc(i,j)=toc(i,j)-tov(kk,ibj)
endif
enddo
enddo
enddo
! send messages from check nodes to variable nodes
do i=1,M
tanhtoc(1:5,i)=tanh(-toc(1:5,i)/2)
enddo
do j=1,N
do i=1,ncw(j)
ichk=Mn(i,j) ! Mn(:,j) are the checks that include bit j
Tmn=product(tanhtoc(1:nrw(ichk),ichk),mask=Nm(1:nrw(ichk),ichk).ne.j)
call platanh(-Tmn,y)
! y=atanh(-Tmn)
tov(i,j)=2*y
enddo
enddo
enddo
niterations=-1
return
end subroutine bpdecode300