along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
+#include <limits.h>
+#include <math.h>
#include <stdbool.h>
#include <stdint.h>
+#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ccan/darray/darray.h"
#include "strgrp.h"
#include "config.h"
+#if HAVE_OPENMP
+#include <omp.h>
+#else
+#define omp_get_max_threads() 1
+#define omp_get_thread_num() 0
+#endif
+
+#define CHAR_N_VALUES (1 << CHAR_BIT)
+
typedef darray(struct strgrp_grp *) darray_grp;
typedef darray(struct strgrp_item *) darray_item;
double score;
};
+struct cosvec {
+ const char *str;
+ int16_t pop[CHAR_N_VALUES];
+};
+
typedef darray(struct grp_score *) darray_score;
struct strgrp {
unsigned int n_grps;
darray_grp grps;
struct grp_score *scores;
+ int32_t n_cosvecs;
+ struct cosvec *cosvecs;
};
struct strgrp_iter {
void *value;
};
+
+/* String vector cosine similarity[1]
+ *
+ * [1] http://blog.nishtahir.com/2015/09/19/fuzzy-string-matching-using-cosine-similarity/
+ */
+
+static inline void
+strpopcnt(struct cosvec *ctx) {
+ const char *c;
+ memset(ctx->pop, 0, CHAR_N_VALUES * sizeof(int16_t));
+ for(c = ctx->str; *c; c++) {
+ assert(*c >= 0);
+ ctx->pop[(unsigned char)*c]++;
+ }
+}
+
+static inline double
+strcossim(struct cosvec *avec, struct cosvec *bvec) {
+ strpopcnt(avec);
+ strpopcnt(bvec);
+ int32_t saibi = 0;
+ int32_t sai2 = 0;
+ int32_t sbi2 = 0;
+ size_t i;
+ for (i = 0; i < CHAR_N_VALUES; i++) {
+ saibi += avec->pop[i] * bvec->pop[i];
+ sai2 += avec->pop[i] * avec->pop[i];
+ sbi2 += bvec->pop[i] * bvec->pop[i];
+ }
+ return saibi / (sqrt(sai2) * sqrt(sbi2));
+}
+
+/* Low-cost filter functions */
+
+static inline bool
+should_grp_score_cos(const struct strgrp *const ctx, struct cosvec *const avec,
+ struct cosvec *const bvec) {
+ return ctx->threshold <= strcossim(avec, bvec);
+}
+
+static inline bool
+should_grp_score_len(const struct strgrp *const ctx,
+ const struct strgrp_grp *const grp, const char *const str) {
+ const size_t strl = strlen(str);
+ const size_t keyl = grp->key_len;
+ double sr = strl / keyl;
+ if (1 < sr) {
+ sr = 1 / sr;
+ }
+ return ctx->threshold <= sr;
+}
+
+/* Scoring - Longest Common Subsequence[2]
+ *
+ * [2] https://en.wikipedia.org/wiki/Longest_common_subsequence_problem
+ */
#define ROWS 2
static inline int cmi(int i, int j) {
return 2 * lcss / (strlen(a) + strlen(b));
}
-static bool
-should_grp_score(const struct strgrp *const ctx,
- const struct strgrp_grp *const grp, const char *const str) {
- const size_t strl = strlen(str);
- const size_t keyl = grp->key_len;
- double sr = strl / keyl;
- if (1 < sr) {
- sr = 1 / sr;
- }
- return ctx->threshold <= sr;
-}
-
static inline double
grp_score(const struct strgrp_grp *const grp, const char *const str) {
return nlcs(grp->key, str);
}
+/* Structure management */
+
static struct strgrp_item *
new_item(tal_t *const tctx, const char *const str, void *const data) {
struct strgrp_item *i = talz(tctx, struct strgrp_item);
struct strgrp *ctx = talz(NULL, struct strgrp);
ctx->threshold = threshold;
stringmap_init(ctx->known, NULL);
+ // n threads compare strings
+ ctx->n_cosvecs = 2 * omp_get_max_threads();
+ ctx->cosvecs = tal_arrz(ctx, struct cosvec, ctx->n_cosvecs);
darray_init(ctx->grps);
return ctx;
}
*(stringmap_enter(ctx->known, str)) = grp;
}
+static inline struct cosvec *
+tl_avec(struct strgrp *ctx) {
+ return &ctx->cosvecs[omp_get_thread_num()];
+}
+
+static inline struct cosvec *
+tl_bvec(struct strgrp *ctx) {
+ return &ctx->cosvecs[omp_get_thread_num() + 1];
+}
+
static struct strgrp_grp *
grp_for(struct strgrp *const ctx, const char *const str) {
if (!ctx->n_grps) {
#endif
for (i = 0; i < ctx->n_grps; i++) {
ctx->scores[i].grp = darray_item(ctx->grps, i);
- const bool ss = should_grp_score(ctx, ctx->scores[i].grp, str);
- ctx->scores[i].score = ss ? grp_score(ctx->scores[i].grp, str) : 0;
+ if (should_grp_score_len(ctx, ctx->scores[i].grp, str)) {
+ tl_avec(ctx)->str = ctx->scores[i].grp->key;
+ tl_bvec(ctx)->str = str;
+ if (should_grp_score_cos(ctx, tl_avec(ctx), tl_bvec(ctx))) {
+ ctx->scores[i].score = grp_score(ctx->scores[i].grp, str);
+ } else {
+ ctx->scores[i].score = 0;
+ }
+ } else {
+ ctx->scores[i].score = 0;
+ }
}
struct grp_score *max = NULL;
for (i = 0; i < ctx->n_grps; i++) {
strgrp_free(ctx);
}
-#include <stdio.h>
-
static void
print_item(const struct strgrp_item *item) {
printf("\t%s\n", item->key);