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reduced code duplication with lambda update()

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This commit is contained in:
Ahmet Inan 2020-06-11 12:29:22 +02:00
commit 619d8bd3b4
1 changed files with 15 additions and 30 deletions
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45
short_bch_code_decoder.hh
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@ -70,21 +70,24 @@ public:
// metric of hard decision
int best = metric(code, word);
int next = -1;
auto update = [code, &word, &best, &next](int hard) {
if (hard == word)
return;
int met = metric(code, hard);
if (met > best) {
next = best;
best = met;
word = hard;
} else if (met > next) {
next = met;
}
};
// flip each bit and see ..
if (0) {
for (int j = 0; j < N; ++j) {
int tmp = 1 << j;
int dec = (*this)(cw ^ tmp);
if (dec == word)
continue;
int met = metric(code, dec);
if (met > best) {
next = best;
best = met;
word = dec;
} else if (met > next) {
next = met;
}
update(dec);
}
}
// Chase algorithm
@ -104,32 +107,14 @@ public:
for (int i = 0; i < T; ++i)
tmp |= ((j>>i)&1) << worst[i];
int dec = (*this)(cw ^ tmp);
if (dec == word)
continue;
int met = metric(code, dec);
if (met > best) {
next = best;
best = met;
word = dec;
} else if (met > next) {
next = met;
}
update(dec);
}
}
// maximum likelihood
if (K <= 6) {
for (int msg = 0; msg < W; ++msg) {
int enc = (msg << P) | par[msg];
if (enc == word)
continue;
int met = metric(code, enc);
if (met > best) {
next = best;
best = met;
word = enc;
} else if (met > next) {
next = met;
}
update(enc);
}
}
if (best == next)