InterpreterApi

Interface to TensorFlow Lite model interpreter, excluding experimental methods.

An InterpreterApi instance encapsulates a pre-trained TensorFlow Lite model, in which operations are executed for model inference.

For example, if a model takes only one input and returns only one output:

try (InterpreterApi interpreter =
     new InterpreterApi.create(file_of_a_tensorflowlite_model)) {
   interpreter.run(input, output);
 }
 

If a model takes multiple inputs or outputs:

Object[] inputs = {input0, input1, ...};
 Map<Integer, Object> map_of_indices_to_outputs = new HashMap<>();
 FloatBuffer ith_output = FloatBuffer.allocateDirect(3 * 2 * 4);  // Float tensor, shape 3x2x4.
 ith_output.order(ByteOrder.nativeOrder());
 map_of_indices_to_outputs.put(i, ith_output);
 try (InterpreterApi interpreter =
     new InterpreterApi.create(file_of_a_tensorflowlite_model)) {
   interpreter.runForMultipleInputsOutputs(inputs, map_of_indices_to_outputs);
 }
 

If a model takes or produces string tensors:

String[] input = {"foo", "bar"};  // Input tensor shape is [2].
 String[][] output = new String[3][2];  // Output tensor shape is [3, 2].
 try (InterpreterApi interpreter =
     new InterpreterApi.create(file_of_a_tensorflowlite_model)) {
   interpreter.runForMultipleInputsOutputs(input, output);
 }
 

Note that there's a distinction between shape [] and shape[1]. For scalar string tensor outputs:

String[] input = {"foo"};  // Input tensor shape is [1].
 ByteBuffer outputBuffer = ByteBuffer.allocate(OUTPUT_BYTES_SIZE);  // Output tensor shape is [].
 try (Interpreter interpreter = new Interpreter(file_of_a_tensorflowlite_model)) {
   interpreter.runForMultipleInputsOutputs(input, outputBuffer);
 }
 byte[] outputBytes = new byte[outputBuffer.remaining()];
 outputBuffer.get(outputBytes);
 // Below, the `charset` can be StandardCharsets.UTF_8.
 String output = new String(outputBytes, charset);
 

Orders of inputs and outputs are determined when converting TensorFlow model to TensorFlowLite model with Toco, as are the default shapes of the inputs.

When inputs are provided as (multi-dimensional) arrays, the corresponding input tensor(s) will be implicitly resized according to that array's shape. When inputs are provided as Buffer types, no implicit resizing is done; the caller must ensure that the Buffer byte size either matches that of the corresponding tensor, or that they first resize the tensor via resizeInput(int, int[]). Tensor shape and type information can be obtained via the Tensor class, available via getInputTensor(int) and getOutputTensor(int).

WARNING:InterpreterApi instances are not thread-safe.

WARNING:An InterpreterApi instance owns resources that must be explicitly freed by invoking close()

The TFLite library is built against NDK API 19. It may work for Android API levels below 19, but is not guaranteed.