1 files changed, 28 insertions, 0 deletions
diff --git a/eval/src/tests/ann/xp-hnsw-wrap.cpp b/eval/src/tests/ann/xp-hnsw-wrap.cpp
index 3eb01142dcd..45c7a974254 100644
--- a/eval/src/tests/ann/xp-hnsw-wrap.cpp
+++ b/eval/src/tests/ann/xp-hnsw-wrap.cpp
@@ -46,6 +46,34 @@ public:
         }
         return result;
     }
+
+    std::vector<NnsHit> topKfilter(uint32_t k, Vector vector, uint32_t search_k, const BitVector &blacklist) override {
+        std::vector<NnsHit> reversed;
+        uint32_t adjusted_k = k+4;
+        uint32_t adjusted_sk = search_k+4;
+        for (int retry = 0; (retry < 5) && (reversed.size() < k); ++retry) {
+            reversed.clear();
+            _hnsw.setEf(adjusted_sk);
+            auto priQ = _hnsw.searchKnn(vector.cbegin(), adjusted_k);
+            while (! priQ.empty()) {
+                auto pair = priQ.top();
+                if (! blacklist.isSet(pair.second)) {
+                    reversed.emplace_back(pair.second, SqDist(pair.first));
+                }
+                priQ.pop();
+            }
+            double got = 1 + reversed.size();
+            double factor = 1.25 * k / got;
+            adjusted_k *= factor;
+            adjusted_sk *= factor;
+        }
+        std::vector<NnsHit> result;
+        while (result.size() < k && !reversed.empty()) {
+            result.push_back(reversed.back());
+            reversed.pop_back();
+        }
+        return result;
+    }
 };
 
 std::unique_ptr<NNS<float>>