Changeset: 097357023ff2 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=097357023ff2
Modified Files:
gdk/gdk_sample.c
Branch: stratified_sampling
Log Message:
Correctly check for negative weights in weighted sample.
diffs (73 lines):
diff --git a/gdk/gdk_sample.c b/gdk/gdk_sample.c
--- a/gdk/gdk_sample.c
+++ b/gdk/gdk_sample.c
@@ -242,12 +242,12 @@ BATsample(BAT *b, BUN n)
BAT *
BATweightedsample(BAT *b, BUN n, BAT *w)
{//TODO test correctness extensively
- BAT* weights;
- bit weights_are_cast;
- BAT* sample;
- oid* oids;/* points to the oids in sample */
- dbl* w_ptr;//TODO types of w
- dbl* keys;/* keys as defined in Alg-A-exp */
+ BAT* weights = NULL;
+ bit weights_are_cast = 0;
+ BAT* sample = NULL;
+ oid* oids = NULL; /* points to the oids in sample */
+ dbl* w_ptr = NULL; //TODO types of w
+ dbl* keys = NULL; /* keys as defined in Alg-A-exp */
BUN cnt, i, j;
BUN pos, childpos;
oid item;
@@ -298,20 +298,20 @@ BATweightedsample(BAT *b, BUN n, BAT *w)
}
BATsetcount(sample, n);
- /* obtain sample */
+ /* obtain sample */
/* Initialize prioqueue */
- i=0;/* i indices the initial sample (filled with elements with non-zero
weight) */
- /* j indices the oids and weights */
- for(j=0; i < n && j < cnt; j++) {
+ i = 0; /* i indices the initial sample (filled with elements with
non-zero weight) */
+ /* j indices the oids and weights */
+ for(j = 0; i < n && j < cnt; j++) {
if(w_ptr[j] == 0.0)
continue;
if(w_ptr[j] < 0.0) {
GDKerror("BATsample: w contains negative weights\n");
goto bailout;
}
- oids[i] = (oid)(j+minoid);
- keys[i] = pow(mtwist_drand(mt_rng),1.0/w_ptr[j]);//TODO cast
1.0 to dbl?
+ oids[i] = (oid)(j + minoid);
+ keys[i] = pow(mtwist_drand(mt_rng), 1.0 / w_ptr[j]);//TODO cast
1.0 to dbl?
i++;
}
@@ -325,8 +325,13 @@ BATweightedsample(BAT *b, BUN n, BAT *w)
while(true) {
r = mtwist_drand(mt_rng);
xw = log(r)/log(keys[0]);
- for(;j<cnt && xw >= w_ptr[j]; j++)
+ for(; j < cnt && xw >= w_ptr[j]; j++) {
+ if(w_ptr[j] < 0.0) {
+ GDKerror("BATsample: w contains negative
weights\n");
+ goto bailout;
+ }
xw -= w_ptr[j];
+ }
if(j >= cnt) break;
/* At this point:
@@ -358,7 +363,7 @@ BATweightedsample(BAT *b, BUN n, BAT *w)
return sample;
- bailout:
+bailout:
if(weights_are_cast && weights)//if weights where converted, delete
converted BAT
BBPunfix(weights->batCacheid);
if(keys)
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