#89 do normalize() for IP test

Former-commit-id: 11be41ee43e3dd0e2ecbcd50ba70bab2df58688d

core/src/index/unittest/faiss_benchmark/faiss_benchmark_test.cpp

@@ -54,6 +54,20 @@ elapsed() {
     return tv.tv_sec + tv.tv_usec * 1e-6;
 }
 
+void normalize(float* arr, size_t nq, size_t dim) {
+    for (size_t i = 0; i < nq; i++) {
+        double vecLen = 0.0;
+        for (size_t j = 0; j < dim; j++) {
+            double val = arr[i * dim + j];
+            vecLen += val * val;
+        }
+        vecLen = std::sqrt(vecLen);
+        for (size_t j = 0; j < dim; j++) {
+            arr[i * dim + j] = (float) (arr[i * dim + j] / vecLen);
+        }
+    }
+}
+
 void*
 hdf5_read(const char* file_name, const char* dataset_name, H5T_class_t dataset_class, size_t& d_out, size_t& n_out) {
     hid_t file, dataset, datatype, dataspace, memspace;
@@ -237,6 +251,11 @@ test_ann_hdf5(const std::string& ann_test_name, const std::string& index_key, in
         float* xb = (float*)hdf5_read(ann_file_name.c_str(), "train", H5T_FLOAT, d, nb);
         assert(d == dim || !"dataset does not have correct dimension");
 
+        if (metric_type == faiss::METRIC_INNER_PRODUCT) {
+            printf("[%.3f s] Normalizing data set \n", elapsed() - t0);
+            normalize(xb, nb, d);
+        }
+
         printf("[%.3f s] Preparing index \"%s\" d=%ld\n", elapsed() - t0, index_key.c_str(), d);
 
         index = faiss::index_factory(d, index_key.c_str(), metric_type);