title: TFException: Expects arg[0] to be string but float is provided (Unity3d)
body: <p>I am using Speech Commands Model Example from <a href="https://github.com/tensorflow/tensorflow/tree/r1.7/tensorflow/examples/speech_commands" rel="nofollow noreferrer">TensorFlow</a> with the variables in Unity3d:</p>
  
  <pre><code>string WAV_INPUT = "wav_data";
          string SOFTMAX_NAME = "labels_softmax";
          string[] outputScoresNames = new string[] { SOFTMAX_NAME };
  </code></pre>
  
  <p>and then add input to the model like this:</p>
  
  <pre><code> private void recognize(float[] audioFile)
      {
          //labels_softmax:0 output name 
          //labels wav_data:0 input name from model 
          string WAV_INPUT = "wav_data";
          string SOFTMAX_NAME = "labels_softmax";
          string[] outputScoresNames = new string[] { SOFTMAX_NAME };
  
          int how_many_labels = 4;
          string[] labels = new string[] { "_silence_" , "_unknown_", "stop","go"};
  
           TextAsset model = Resources.Load("GoStop") as TextAsset;
           TFGraph  graph = new TFGraph();
           graph.Import(model.bytes);
  
          TFSession session = new TFSession(graph);
  
          var runner = session.GetRunner();
  
          runner.AddInput(graph[WAV_INPUT][0], audioFile);
          runner.AddTarget(outputScoresNames);
          runner.Run();
         // float[] recurrent_tensor = runner.Run()[0].GetValue() as float[];
  
      }
  </code></pre>
  
  <p>and the exception given for softmax is like that:</p>
  
  <pre><code>TFException: Expects arg[0] to be string but float is provided
  TensorFlow.TFStatus.CheckMaybeRaise (TensorFlow.TFStatus incomingStatus, System.Boolean last) (at &lt;1fe2de69842a4a4ba15256b83cca05f3&gt;:0)
  TensorFlow.TFSession.Run (TensorFlow.TFOutput[] inputs, TensorFlow.TFTensor[] inputValues, TensorFlow.TFOutput[] outputs, TensorFlow.TFOperation[] targetOpers, TensorFlow.TFBuffer runMetadata, TensorFlow.TFBuffer runOptions, TensorFlow.TFStatus status) (at &lt;1fe2de69842a4a4ba15256b83cca05f3&gt;:0)
  TensorFlow.TFSession+Runner.Run (TensorFlow.TFStatus status) (at &lt;1fe2de69842a4a4ba15256b83cca05f3&gt;:0)
  tensor.recognize (System.Single[] audioFile) (at Assets/tensor.cs:51)
  tensor.Start () (at Assets/tensor.cs:23)
  </code></pre>
  
  <p>is it a casting problem?and how to manage it to work with TensorFlowSharp? </p>