Code comment.

dmlc · Apr 21, 2023 · 916237f · 916237f
1 parent ee5a9af
commit 916237f
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Showing 2 changed files with 4 additions and 3 deletions.
diff --git a/src/data/iterative_dmatrix.cc b/src/data/iterative_dmatrix.cc
@@ -301,8 +301,8 @@ BatchSet<GHistIndexMatrix> IterativeDMatrix::GetGradientIndex(Context const* ctx
     } else if (fmat_ctx_.IsCPU()) {
       ghist_ = std::make_shared<GHistIndexMatrix>(&fmat_ctx_, Info(), *ellpack_, param);
     } else {
-      // Can happen when QDM is initialized on GPU, but a CPU version is queried by to_csr
-      // or the predictor.
+      // Can happen when QDM is initialized on GPU, but a CPU version is queried by a different QDM
+      // for cut reference.
       auto cpu_ctx = ctx->MakeCPU();
       ghist_ = std::make_shared<GHistIndexMatrix>(&cpu_ctx, Info(), *ellpack_, param);
     }

diff --git a/src/data/iterative_dmatrix.cu b/src/data/iterative_dmatrix.cu
@@ -192,7 +192,8 @@ BatchSet<EllpackPage> IterativeDMatrix::GetEllpackBatches(Context const* ctx,
       *ellpack_->Impl() =
           EllpackPageImpl(&fmat_ctx_, *this->ghist_, this->Info().feature_types.ConstDeviceSpan());
     } else {
-      // Can happen when QDM is initialized on CPU, but a GPU version is queried by the predictor.
+      // Can happen when QDM is initialized on CPU, but a GPU version is queried by a different QDM
+      // for cut reference.
       auto cuda_ctx = ctx->MakeCUDA();
       this->Info().feature_types.SetDevice(cuda_ctx.gpu_id);
       *ellpack_->Impl() =