From aea83912f9464c5fea0e855cb60ccf398d7fad60 Mon Sep 17 00:00:00 2001
From: Koan-Sin Tan <koansin.tan@gmail.com>
Date: Fri, 8 Nov 2019 15:39:23 +0800
Subject: [PATCH] enable NNAPI in CPU path

With NNAPI delegate added, Android devices with floating point
NNAPI device(s) could run facedectioncpu and objectdectioncpu
accelerated. On device without accelerators, tflite interpreter
will simple fall back to CPU.
---
 mediapipe/calculators/tflite/tflite_inference_calculator.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mediapipe/calculators/tflite/tflite_inference_calculator.cc b/mediapipe/calculators/tflite/tflite_inference_calculator.cc
index ebd632df9..e21087e9b 100644
--- a/mediapipe/calculators/tflite/tflite_inference_calculator.cc
+++ b/mediapipe/calculators/tflite/tflite_inference_calculator.cc
@@ -305,6 +305,10 @@ REGISTER_CALCULATOR(TfLiteInferenceCalculator);
 #endif
   } else {
     // Read CPU input into tensors.
+    interpreter_->SetAllowFp16PrecisionForFp32(1);
+    delegate_ = tflite::NnApiDelegate();
+    interpreter_->ModifyGraphWithDelegate(delegate_);
+
     const auto& input_tensors =
         cc->Inputs().Tag("TENSORS").Get<std::vector<TfLiteTensor>>();
     RET_CHECK_GT(input_tensors.size(), 0);