Changeset: 5f5feac01939 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/5f5feac01939
Modified Files:
gdk/gdk_histogram.c
Branch: histograms
Log Message:
Initial attempt for strings histogram
diffs (164 lines):
diff --git a/gdk/gdk_histogram.c b/gdk/gdk_histogram.c
--- a/gdk/gdk_histogram.c
+++ b/gdk/gdk_histogram.c
@@ -25,6 +25,7 @@
static_assert(NBUCKETS > 2, "The number of buckets must be > 2");
static_assert(SAMPLE_SIZE > NBUCKETS, "The sample size must be > number of
buckets");
static_assert(SAMPLE_SIZE < INT_MAX, "The sample size must be on the integer
range");
+static_assert((SAMPLE_SIZE % NBUCKETS) == 0, "The sample size must be a
multiple of the number of buckets");
#ifdef HAVE_HGE
#define VAR_UPCAST hge
@@ -59,6 +60,7 @@ can_create_histogram(int tpe)
#ifdef HAVE_HGE
case TYPE_hge:
#endif
+ case TYPE_str:
return true;
default: /* type not supported */
return false;
@@ -183,6 +185,7 @@ create_perfect_histogram(BAT *sam, Histo
break;
#endif
default:
+ /* no perfect histograms on strings yet */
assert(0);
}
return h;
@@ -270,6 +273,56 @@ create_generic_histogram(BAT *sam, Histo
generic_histogram_loop(hge, abshge);
break;
#endif
+ case TYPE_str: { /* for strings use the hashed value (it cannot be used
in ranges) */
+ int i = 0;
+ const int gap = SAMPLE_SIZE / NBUCKETS;
+ HistogramBucket_int *restrict hist;
+
+ h->nbuckets = NBUCKETS;
+ if (!(h->histogram = GDKmalloc(sizeof(HistogramBucket_int) *
h->nbuckets)))
+ return NULL;
+
+ hist = (HistogramBucket_int *) h->histogram;
+ for (BUN k = 0 ; k < NBUCKETS ; k++) {
+ HistogramBucket_int *restrict b = &(hist[k]);
+ b->min = i;
+ i += gap;
+ b->max = i;
+ b->count = 0;
+ }
+
+ BATiter bi = bat_iterator(sam);
+ BUN c = bi.count;
+ for (BUN k = 0 ; k < c ; k++) { /* Now create the histogram */
+ const char *next = BUNtvar(bi, k);
+
+ if (strNil(next)) {
+ nulls++;
+ } else {
+ bool found = false;
+ int l = 0, r = NBUCKETS - 1;
+ /* pick the lowest bits according to the sample
size from the hash value */
+ int value = (int)(strHash(next) & (SAMPLE_SIZE
- 1));
+
+ while (l <= r) { /* Do binary search to find
the bucket */
+ int m = l + (r - l) / 2;
+ HistogramBucket_int *restrict b =
&(hist[m]);
+ if (value >= b->min && value < b->max) {
+ b->count++;
+ found = true;
+ break;
+ } else if (value < b->min) { /* value
is smaller, ignore right half */
+ r = m - 1;
+ } else { /* value is greater, ignore
left half */
+ l = m + 1;
+ }
+ }
+ assert(found); /* the value must be found */
+ }
+ }
+ bat_iterator_end(&bi);
+ h->nulls = nulls;
+ } break;
default:
assert(0);
}
@@ -306,7 +359,7 @@ HISTOGRAMcreate(BAT *b)
BAT *sids, *sam;
Histogram *h;
bool perfect_histogram = false;
- ValRecord min, max, diff = {.vtype = VAR_TPE}, conv =
{.vtype = VAR_TPE}, nbuckets = {.vtype = VAR_TPE}, truth = {.vtype = TYPE_bit};
+ ValRecord min = {.vtype = bi.type}, max = {.vtype =
bi.type};
if (!(sids = BATsample_with_seed(b, SAMPLE_SIZE,
(uint64_t) GDKusec() * (uint64_t) b->batCacheid)))
goto fail;
@@ -315,27 +368,31 @@ HISTOGRAMcreate(BAT *b)
if (!sam)
goto fail;
- if (bi.type == TYPE_bit) {
- VALinit(&min, TYPE_bit, &(bit){0});
- VALinit(&max, TYPE_bit, &(bit){1});
- perfect_histogram = true;
- } else {
- min_and_max_values(&bi, &min, &max);
- if (VARcalcsub(&diff, &max, &min, true) ==
GDK_SUCCEED) {
- if (VARconvert(&conv, &diff, true, 0,
0, 0) == GDK_SUCCEED) {
- VAR_UPCAST v = (VAR_UPCAST)
NBUCKETS;
- VALinit(&nbuckets, VAR_TPE, &v);
- /* if the number of buckets is
greater than max and min difference, then there is a 'perfect' histogram */
- if (VARcalcgt(&truth,
&nbuckets, &conv) == GDK_SUCCEED) {
- perfect_histogram =
truth.val.btval == 1;
+ if (ATOMbasetype(bi.type) != TYPE_str) {
+ ValRecord diff = {.vtype = VAR_TPE}, conv =
{.vtype = VAR_TPE}, nbuckets = {.vtype = VAR_TPE}, truth = {.vtype = TYPE_bit};
+
+ if (bi.type == TYPE_bit) {
+ VALinit(&min, TYPE_bit, &(bit){0});
+ VALinit(&max, TYPE_bit, &(bit){1});
+ perfect_histogram = true;
+ } else {
+ min_and_max_values(&bi, &min, &max);
+ if (VARcalcsub(&diff, &max, &min, true)
== GDK_SUCCEED) {
+ if (VARconvert(&conv, &diff,
true, 0, 0, 0) == GDK_SUCCEED) {
+ VAR_UPCAST v =
(VAR_UPCAST) NBUCKETS;
+ VALinit(&nbuckets,
VAR_TPE, &v);
+ /* if the number of
buckets is greater than max and min difference, then there is a 'perfect'
histogram */
+ if (VARcalcgt(&truth,
&nbuckets, &conv) == GDK_SUCCEED) {
+
perfect_histogram = truth.val.btval == 1;
+ } else {
+ GDKclrerr();
+ }
} else {
GDKclrerr();
}
} else {
GDKclrerr();
}
- } else {
- GDKclrerr();
}
}
@@ -373,6 +430,7 @@ fail:
#define histogram_print_loop(TPE) \
do { \
+ ssize_t (*atomtostr)(str *, size_t *, const void *, bool) =
BATatoms[TYPE_##TPE].atomToStr; \
HistogramBucket_##TPE *restrict hist = (HistogramBucket_##TPE
*) b->thistogram->histogram; \
for (int i = 0 ; i < nbuckets ; i++) { \
HistogramBucket_##TPE *restrict hb = &(hist[i]); \
@@ -407,7 +465,6 @@ HISTOGRAMprint(BAT *b)
size_t len = 0, rlen = 2048, minlen = 256, maxlen = 256;
str res = NULL, minbuf = NULL, maxbuf = NULL;
int tpe = ATOMbasetype(b->ttype), nbuckets;
- ssize_t (*atomtostr)(str *, size_t *, const void *, bool) =
BATatoms[b->ttype].atomToStr;
if (VIEWtparent(b)) /* don't look on views */
b = BBP_cache(VIEWtparent(b));
@@ -438,6 +495,7 @@ HISTOGRAMprint(BAT *b)
case TYPE_sht:
histogram_print_loop(sht);
break;
+ case TYPE_str: /* strings use integer size buckets */
case TYPE_int:
histogram_print_loop(int);
break;
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