Fix Hexagon unit tests by reducing min nodes per partitions to 1

PiperOrigin-RevId: 306667501
Change-Id: Id91da849cd77dd8861786841d8194c5e6d2a04fb

tensorflow/lite/experimental/delegates/hexagon/builders/tests/hexagon_delegate_op_model.h

@@ -44,6 +44,8 @@ class SingleOpModelWithHexagon : public SingleOpModel {
         "vendor/lib/rfsa/adsp;/dsp",
         1 /*overwrite*/);
 
+    // For tests, we use one-op-models.
+    params_.min_nodes_per_partition = 1;
     auto* delegate_ptr = TfLiteHexagonDelegateCreate(&params_);
     ASSERT_TRUE(delegate_ptr != nullptr);
     delegate_ = Interpreter::TfLiteDelegatePtr(

tensorflow/lite/experimental/delegates/hexagon/hexagon_delegate.cc

@@ -95,7 +95,7 @@ TfLiteStatus DelegatePrepare(TfLiteContext* context, TfLiteDelegate* delegate) {
   TfLiteHexagonDelegateOptions* params =
       static_cast<TfLiteHexagonDelegateOptions*>(delegate->data_);
   const auto delegate_partitions = helper.GetFirstNLargestPartitions(
-      params->max_delegated_partitions, kMinNodesPerHexagonGraph);
+      params->max_delegated_partitions, params->min_nodes_per_partition);
 
   // To avoid creating a new TfLiteIntArray and free it later, we reserve one
   // element to represent TfLiteIntArray.size which is the 1st element of
@@ -133,6 +133,9 @@ class HexagonDelegate : public TfLiteDelegate {
                       params_.max_delegated_partitions, kMaxMaxHexagonGraphs);
       params_.max_delegated_partitions = kMaxMaxHexagonGraphs;
     }
+    if (params_.min_nodes_per_partition <= 0) {
+      params_.min_nodes_per_partition = kMinNodesPerHexagonGraph;
+    }
   }
 
   TfLiteHexagonDelegateOptions* params() { return &params_; }

tensorflow/lite/experimental/delegates/hexagon/hexagon_delegate.h

@@ -55,6 +55,9 @@ struct TFL_CAPI_EXPORT TfLiteHexagonDelegateOptions {
   // hexagon_nn_init. Each graph corresponds to one delegated node subset in the
   // TFLite model.
   int max_delegated_partitions;
+  // This sets the minimum number of nodes per graph created with
+  // hexagon_nn_init. Defaults to 2.
+  int min_nodes_per_partition;
 };
 
 // Return a delegate that uses Hexagon SDK for ops execution.