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pseudocount(): Refactor the 4 checks into a function
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Also consolidate the pseudocount comments.
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@ampli
ampli committed Feb 13, 2024
1 parent 1021183 commit 2112df2
Showing 1 changed file with 66 additions and 79 deletions.
145 changes: 66 additions & 79 deletions link-grammar/parse/count.c
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Original file line number Diff line number Diff line change
Expand Up @@ -948,37 +948,66 @@ static bool is_panic(count_context_t *ctxt)
#endif
Count_bin count_unknown = INIT_NO_COUNT;

/**
* psuedocount is used to check to see if a parse is even possible,
* so that we don't waste CPU time performing an actual count, only
* to discover that it is zero.
*
* A table entry with a count 0 indicates that the parse is not possible.
* In that case we can skip parsing. If it is not 0, it is the parse
* result and we can use it and skip parsing too.
* However, if an entry is not in the hash table, we have to assume the
* worst case: that the count might be non-zero. To indicate that case,
* return the special sentinel value \c count_unknown.
/*
* Lookup the tracon table for the count of the given range. If exists,
* return it. Else return the sentinel value \c count_unknown.
*/
static Count_bin pseudocount(count_context_t * ctxt,
int lw, int rw, Connector *le, Connector *re,
unsigned int null_count)
static Count_bin table_count(count_context_t * ctxt,
int lw, int rw, Connector *le, Connector *re,
unsigned int null_count)
{
if (!USE_TABLE_TRACON) return true;

/* This check is not necessary for correctness, but it saves CPU time.
* If a cross link would result, immediately return 0. Note that there is
* no need to check here if the nearest_word fields are in the range
* [lw, rw] due to the way start_word/end_word are computed, and due to
* nearest_word checks in form_match_list(). */
* If a cross link would result, we know that the count would be 0.
* Note that there is no need to check here if the nearest_word fields
* are in the range [lw, rw] due to the way start_word/end_word are
* computed, and due to nearest_word checks in form_match_list(). */
if ((le != NULL) && (re != NULL) && (le->nearest_word > re->nearest_word))
return hist_zero();

if (!USE_TABLE_TRACON) return count_unknown;

Count_bin *count = table_lookup(ctxt, lw, rw, le, re, null_count, NULL);
if (NULL == count) return count_unknown;
return *count;
}

/**
* Check to see if a parse is even possible, so that we don't later waste
* CPU time performing an actual count, only to discover that it is zero.
*
* Depending whether the end connectors of the given range are multi or
* not, up to 4 components need to be summed up to yield its count. Lookup
* them in the tracon table, and return false iff all of them are found to
* be zero.
*
* In case a non-zero table entry (or \c count_unknown) is found, cache it
* in \p count.
*/
static bool pseudocount(count_context_t * ctxt, Count_bin *count,
int lw, int rw, Connector *le, Connector *re,
unsigned int null_count)
{
count[0] = table_count(ctxt, lw, rw, le->next, re->next, null_count);
if (hist_total(&count[0]) != 0) return true;
if (le->multi)
{
count[1] = table_count(ctxt, lw, rw, le, re->next, null_count);
if (hist_total(&count[1]) != 0) return true;
}
if (re->multi)
{
count[2] = table_count(ctxt, lw, rw, le->next, re, null_count);
if (hist_total(&count[2]) != 0) return true;;
}
if (le->multi && re->multi)
{
count[3] = table_count(ctxt, lw, rw, le, re, null_count);
if (hist_total(&count[3]) != 0) return true;;
}

return false;
}

/**
* Return the number of optional words strictly between w1 and w2.
*/
Expand Down Expand Up @@ -1417,15 +1446,7 @@ static Count_bin do_count(
rightpcount = false;
}

Count_bin l_any = INIT_NO_COUNT;
Count_bin r_any = INIT_NO_COUNT;
Count_bin l_cmulti = INIT_NO_COUNT;
Count_bin l_dmulti = INIT_NO_COUNT;
Count_bin l_dcmulti = INIT_NO_COUNT;
Count_bin l_bnr = INIT_NO_COUNT;
Count_bin r_cmulti = INIT_NO_COUNT;
Count_bin r_dmulti = INIT_NO_COUNT;
Count_bin r_dcmulti = INIT_NO_COUNT;
Count_bin r_bnl = (le == NULL) ? INIT_NO_COUNT : hist_zero();

/* Now, we determine if (based on table only) we can see that
Expand All @@ -1439,68 +1460,34 @@ static Count_bin do_count(
* the pseudocount is zero, then we know that the true
* count will be zero.
*
* Cache the result in the l_* and r_* variables, so a table
* Cache the result in the lcount and rcount arrays, so a table
* lookup can be skipped in cases we cannot skip the actual
* calculation and a table entry exists. */
Count_bin lcount[4] = { NO_COUNT, NO_COUNT, NO_COUNT, NO_COUNT };
if (Lmatch && !leftpcount)
{
l_any = pseudocount(ctxt, lw, w, le->next, d->left->next, lnull_cnt);
leftpcount = (hist_total(&l_any) != 0);
if (!leftpcount && le->multi)
{
l_cmulti =
pseudocount(ctxt, lw, w, le, d->left->next, lnull_cnt);
leftpcount |= (hist_total(&l_cmulti) != 0);
}
if (!leftpcount && d->left->multi)
{
l_dmulti =
pseudocount(ctxt, lw, w, le->next, d->left, lnull_cnt);
leftpcount |= (hist_total(&l_dmulti) != 0);
}
if (!leftpcount && le->multi && d->left->multi)
{
l_dcmulti =
pseudocount(ctxt, lw, w, le, d->left, lnull_cnt);
leftpcount |= (hist_total(&l_dcmulti) != 0);
}
leftpcount =
pseudocount(ctxt, lcount, lw, w, le, d->left, lnull_cnt);
}

Count_bin rcount[4] = { NO_COUNT, NO_COUNT, NO_COUNT, NO_COUNT };
if (Rmatch && !rightpcount && (leftpcount || (le == NULL)))
{
r_any = pseudocount(ctxt, w, rw, d->right->next, re->next, rnull_cnt);
rightpcount = (hist_total(&r_any) != 0);
if (!rightpcount && re->multi)
{
r_cmulti =
pseudocount(ctxt, w, rw, d->right->next, re, rnull_cnt);
rightpcount |= (hist_total(&r_cmulti) != 0);
}
if (!rightpcount && d->right->multi)
{
r_dmulti =
pseudocount(ctxt, w,rw, d->right, re->next, rnull_cnt);
rightpcount |= (hist_total(&r_dmulti) != 0);
}
if (!rightpcount && d->right->multi && re->multi)
{
r_dcmulti =
pseudocount(ctxt, w, rw, d->right, re, rnull_cnt);
rightpcount |= (hist_total(&r_dcmulti) != 0);
}
rightpcount =
pseudocount(ctxt, rcount, w, rw, d->right, re, rnull_cnt);
}

/* Perform a table lookup for a possible cyclic solution. */
if (leftpcount)
{
l_bnr = pseudocount(ctxt, w, rw, d->right, re, rnull_cnt);
l_bnr = table_count(ctxt, w, rw, d->right, re, rnull_cnt);
}
else
{
if (!rightpcount) continue; /* Left and right counts are 0. */
if (le == NULL)
{
r_bnl = pseudocount(ctxt, lw, w, le, d->left, lnull_cnt);
r_bnl = table_count(ctxt, lw, w, le, d->left, lnull_cnt);
}
}

Expand All @@ -1527,16 +1514,16 @@ static Count_bin do_count(
{
if (hist_total(&leftcount) == NO_COUNT)
{
CACHE_COUNT(l_any, leftcount = count,
CACHE_COUNT(lcount[0], leftcount = count,
do_count(ctxt, lw, w, le->next, d->left->next, lnull_cnt));
if (le->multi)
CACHE_COUNT(l_cmulti, hist_accumv(&leftcount, d->cost, count),
CACHE_COUNT(lcount[1], hist_accumv(&leftcount, d->cost, count),
do_count(ctxt, lw, w, le, d->left->next, lnull_cnt));
if (d->left->multi)
CACHE_COUNT(l_dmulti, hist_accumv(&leftcount, d->cost, count),
CACHE_COUNT(lcount[2], hist_accumv(&leftcount, d->cost, count),
do_count(ctxt, lw, w, le->next, d->left, lnull_cnt));
if (d->left->multi && le->multi)
CACHE_COUNT(l_dcmulti, hist_accumv(&leftcount, d->cost, count),
CACHE_COUNT(lcount[3], hist_accumv(&leftcount, d->cost, count),
do_count(ctxt, lw, w, le, d->left, lnull_cnt));
}

Expand All @@ -1557,16 +1544,16 @@ static Count_bin do_count(
{
if (hist_total(&rightcount) == NO_COUNT)
{
CACHE_COUNT(r_any, rightcount = count,
CACHE_COUNT(rcount[0], rightcount = count,
do_count(ctxt, w, rw, d->right->next, re->next, rnull_cnt));
if (re->multi)
CACHE_COUNT(r_cmulti, hist_accumv(&rightcount, d->cost, count),
CACHE_COUNT(rcount[1], hist_accumv(&rightcount, d->cost, count),
do_count(ctxt, w, rw, d->right->next, re, rnull_cnt));
if (d->right->multi)
CACHE_COUNT(r_dmulti, hist_accumv(&rightcount, d->cost, count),
CACHE_COUNT(rcount[2], hist_accumv(&rightcount, d->cost, count),
do_count(ctxt, w, rw, d->right, re->next, rnull_cnt));
if (d->right->multi && re->multi)
CACHE_COUNT(r_dcmulti, hist_accumv(&rightcount, d->cost, count),
CACHE_COUNT(rcount[3], hist_accumv(&rightcount, d->cost, count),
do_count(ctxt, w, rw, d->right, re, rnull_cnt));
}

Expand Down

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