Set norm to 1.0 for all-0 vectors (zilliztech#803)

Signed-off-by: Cai Yudong <yudong.cai@zilliz.com>
alexanderguzhva · Sep 3, 2024 · 14818a1 · 14818a1
1 parent 7a6be01
commit 14818a1
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Showing 4 changed files with 12 additions and 8 deletions.
diff --git a/thirdparty/DiskANN/include/diskann/utils.h b/thirdparty/DiskANN/include/diskann/utils.h
@@ -691,7 +691,7 @@ namespace diskann {
     }
 
     for (auto& norm : norms) {
-      norm = std::sqrt(norm);
+      norm = (norm == 0.0 ? 1.0 : std::sqrt(norm));
     }
 
     in_reader.seekg(2 * sizeof(_u32), std::ios::beg);

diff --git a/thirdparty/DiskANN/src/index.cpp b/thirdparty/DiskANN/src/index.cpp
@@ -2990,6 +2990,7 @@ namespace diskann {
     for (unsigned i = 0; i < _nd; i++) {
       char *cur_node_offset = _opt_graph + i * _node_size;
       float cur_norm = norm_l2sqr(_data + i * _aligned_dim, _aligned_dim);
+      cur_norm = (cur_norm == 0.0 ? 1.0 : cur_norm);
       std::memcpy(cur_node_offset, &cur_norm, sizeof(float));
       std::memcpy(cur_node_offset + sizeof(float), _data + i * _aligned_dim,
                   _data_len - sizeof(float));

diff --git a/thirdparty/faiss/faiss/utils/distances.cpp b/thirdparty/faiss/faiss/utils/distances.cpp
@@ -460,11 +460,11 @@ void exhaustive_cosine_seq_impl(
 
             // the lambda that applies a filtered element.
             auto apply = [&resi, y, y_norms, d](const float ip, const idx_t j) {
-                const float norm =
+                float norm =
                     (y_norms != nullptr) ? 
                         y_norms[j] : 
                         sqrtf(fvec_norm_L2sqr(y + j * d, d));
-
+                norm = (norm == 0.0 ? 1.0 : norm);
                 resi.add_result(ip / norm, j);
             };
 
@@ -719,9 +719,10 @@ void exhaustive_cosine_blas(
 
                 for (size_t j = j0; j < j1; j++) {
                     float ip = *ip_line;
-                    float dis = (y_norms_in != nullptr) ? ip / y_norms_in[j]
-                                                        : ip / y_norms[j];
-                    *ip_line = dis;
+                    float norm = (y_norms_in != nullptr) ? y_norms_in[j]
+                                                         : y_norms[j];
+                    norm = (norm == 0.0 ? 1.0 : norm);
+                    *ip_line = ip / norm;
                     ip_line++;
                 }
             }
@@ -1448,10 +1449,11 @@ void knn_cosine_by_idx(
                 break;
             }
             float ip = fvec_inner_product(x_, y + d * idsi[j], d);
-            const float norm =
+            float norm =
                 (y_norms != nullptr) ? 
                     y_norms[idsi[j]] : 
                     sqrtf(fvec_norm_L2sqr(y + d * idsi[j], d));
+            norm = (norm == 0.0 ? 1.0 : norm);
             ip /= norm;
 
             if (ip > simi[0]) {

diff --git a/thirdparty/hnswlib/hnswlib/hnswalg.h b/thirdparty/hnswlib/hnswlib/hnswalg.h
@@ -1236,7 +1236,8 @@ class HierarchicalNSW : public AlgorithmInterface<dist_t> {
         if constexpr (has_raw_data) {
             memcpy(getDataByInternalId(cur_c), data_point, data_size_);
             if (metric_type_ == Metric::COSINE) {
-                data_norm_l2_[cur_c] = std::sqrt(NormSqr<data_t, dist_t>(data_point, dist_func_param_));
+                float norm = NormSqr<data_t, dist_t>(data_point, dist_func_param_);
+                data_norm_l2_[cur_c] = (norm == 0.0 ? 1.0 : std::sqrt(norm));
             }
         }
         if constexpr (sq_enabled) {