Simplify perplexity normalization in t-SNE

P_sum is equal to n. See rapidsai#2622 where I made this change once before. rapidsai#4208 changed it back while consolidating code.
zbjornson · Dec 6, 2021 · 2b02e89 · 2b02e89
1 parent c364d05
commit 2b02e89
Showing 1 changed file with 1 addition and 2 deletions.
diff --git a/cpp/src/tsne/tsne_runner.cuh b/cpp/src/tsne/tsne_runner.cuh
@@ -161,8 +161,7 @@ class TSNE_runner {
     START_TIMER;
     //---------------------------------------------------
     // Normalize perplexity to prepare for symmetrization
-    value_t P_sum = thrust::reduce(rmm::exec_policy(stream), P.begin(), P.end());
-    raft::linalg::scalarMultiply(P.data(), P.data(), 1.0f / (2.0f * P_sum), P.size(), stream);
+    raft::linalg::scalarMultiply(P.data(), P.data(), 1.0f / (2.0f * n), P.size(), stream);
     //---------------------------------------------------
     END_TIMER(NormalizeTime);