diff --git a/src/nnet3/nnet-am-decodable-simple.h b/src/nnet3/nnet-am-decodable-simple.h
index e83b9e4bab2..74a1e75b59a 100644
--- a/src/nnet3/nnet-am-decodable-simple.h
+++ b/src/nnet3/nnet-am-decodable-simple.h
@@ -103,6 +103,39 @@ struct NnetSimpleComputationOptions {
     ParseOptions compute_opts("computation", opts);
     compute_config.Register(&compute_opts);
   }
+
+  void CheckAndFixConfigs(int32 nnet_modulus) {
+    static bool warned_frames_per_chunk = false;
+    if (frame_subsampling_factor < 1 || frames_per_chunk < 1) {
+      KALDI_ERR << "--frame-subsampling-factor and "
+                << "--frames-per-chunk must be > 0";
+    }
+    KALDI_ASSERT(nnet_modulus > 0);
+    int32 n = Lcm(frame_subsampling_factor, nnet_modulus);
+
+    if (frames_per_chunk % n != 0) {
+      // round up to the nearest multiple of n.
+      int32 new_frames_per_chunk = n * ((frames_per_chunk + n - 1) / n);
+      if (!warned_frames_per_chunk) {
+        warned_frames_per_chunk = true;
+        if (nnet_modulus == 1) {
+          // simpler error message.
+          KALDI_LOG << "Increasing --frames-per-chunk from " << frames_per_chunk
+                    << " to " << new_frames_per_chunk
+                    << " to make it a multiple of "
+                    << "--frame-subsampling-factor="
+                    << frame_subsampling_factor;
+        } else {
+          KALDI_LOG << "Increasing --frames-per-chunk from " << frames_per_chunk
+                    << " to " << new_frames_per_chunk << " due to "
+                    << "--frame-subsampling-factor=" << frame_subsampling_factor
+                    << " and "
+                    << "nnet shift-invariance modulus = " << nnet_modulus;
+        }
+      }
+      frames_per_chunk = new_frames_per_chunk;
+    }
+  }
 };
 
 /*
diff --git a/src/nnet3/nnet-batch-compute.cc b/src/nnet3/nnet-batch-compute.cc
index 9d71a021f05..0e07834ed3d 100644
--- a/src/nnet3/nnet-batch-compute.cc
+++ b/src/nnet3/nnet-batch-compute.cc
@@ -38,9 +38,12 @@ NnetBatchComputer::NnetBatchComputer(
     log_priors_(priors),
     num_full_minibatches_(0) {
   log_priors_.ApplyLog();
-  CheckAndFixConfigs();
-  ComputeSimpleNnetContext(nnet, &nnet_left_context_,
-                           &nnet_right_context_);
+  opts_.CheckAndFixConfigs(nnet_.Modulus());
+  KALDI_ASSERT(opts_.minibatch_size >= 1 && opts_.edge_minibatch_size >= 1 &&
+               opts_.partial_minibatch_factor < 1.0 &&
+               opts_.partial_minibatch_factor >= 0.0);
+
+  ComputeSimpleNnetContext(nnet, &nnet_left_context_, &nnet_right_context_);
   input_dim_ = nnet.InputDim("input");
   ivector_dim_ = std::max<int32>(0, nnet.InputDim("ivector"));
   output_dim_ = nnet.OutputDim("output");
@@ -340,49 +343,6 @@ void NnetBatchComputer::GetComputationRequest(
   request->outputs.push_back(IoSpecification("output", output_indexes));
 }
 
-
-
-void NnetBatchComputer::CheckAndFixConfigs() {
-  static bool warned_frames_per_chunk = false;
-  int32 nnet_modulus = nnet_.Modulus();
-  if (opts_.frame_subsampling_factor < 1 ||
-      opts_.frames_per_chunk < 1) {
-    KALDI_ERR << "--frame-subsampling-factor and "
-              << "--frames-per-chunk must be > 0";
-  }
-  KALDI_ASSERT(nnet_modulus > 0);
-  int32 n = Lcm(opts_.frame_subsampling_factor, nnet_modulus);
-
-  if (opts_.frames_per_chunk % n != 0) {
-    // round up to the nearest multiple of n.
-    int32 frames_per_chunk = n * ((opts_.frames_per_chunk + n - 1) / n);
-    if (!warned_frames_per_chunk) {
-      warned_frames_per_chunk = true;
-      if (nnet_modulus == 1) {
-        // simpler error message.
-        KALDI_LOG << "Increasing --frames-per-chunk from "
-                  << opts_.frames_per_chunk << " to "
-                  << frames_per_chunk << " to make it a multiple of "
-                  << "--frame-subsampling-factor="
-                  << opts_.frame_subsampling_factor;
-      } else {
-        KALDI_LOG << "Increasing --frames-per-chunk from "
-                  << opts_.frames_per_chunk << " to "
-                  << frames_per_chunk << " due to "
-                  << "--frame-subsampling-factor="
-                  << opts_.frame_subsampling_factor << " and "
-                  << "nnet shift-invariance modulus = " << nnet_modulus;
-      }
-    }
-    opts_.frames_per_chunk = frames_per_chunk;
-  }
-  KALDI_ASSERT(opts_.minibatch_size >= 1 &&
-               opts_.edge_minibatch_size >= 1 &&
-               opts_.partial_minibatch_factor < 1.0 &&
-               opts_.partial_minibatch_factor >= 0.0);
-}
-
-
 void NnetBatchComputer::FormatInputs(
     int32 minibatch_size,
     const std::vector<NnetInferenceTask*> &tasks,