How to interpret parameters of ONNX model in c#

Question

I have created a Tensoflow model in Python and exported it to an ONNX model to use in C#. The problem is that I don't know how to interpret the input and output parameters of the model in C#. I've seen some posts for specific situations, but for my (pretty simple) model, I can't find out what to do.

My model input and output is as follows: enter image description here

In my C# project I create an input class:

    public class OnnxInput
    {
        [VectorType(1)]
        [ColumnName("input_3")]
        public float[]? Temperaturen { get; set; }
    }

and an output class:

    public class OnnxOutput
    {
        [VectorType(1)]
        [ColumnName("dense_5")]
        public float[]? PredictedTemp { get; set; }
    }

My C# code:

        private void button1_Click(object sender, EventArgs e)
        {
            MLContext mlContext = new MLContext();

            var onnxPredictionPipeline = GetPredictionPipeline(mlContext);

            var onnxPredictionEngine = mlContext.Model.CreatePredictionEngine<OnnxInput, OnnxOutput>(onnxPredictionPipeline);

            var testInput = new OnnxInput
            {
                Temperaturen = new float[] { 1f, 2f, 3f, 4f, 5f }
            };

            var prediction = onnxPredictionEngine.Predict(testInput);

            MessageBox.Show($"Predicted Fare: {prediction.PredictedTemp}");
        }

        static ITransformer GetPredictionPipeline(MLContext mlContext)
        {
            var inputColumns = new string[] {"input_3"};

            var outputColumns = new string[] { "dense_5" };

            var onnxPredictionPipeline =
                mlContext
                    .Transforms
                    .ApplyOnnxModel(
                        outputColumnNames: outputColumns,
                        inputColumnNames: inputColumns,
                        ONNX_MODEL_PATH);

            var emptyDv = mlContext.Data.LoadFromEnumerable(new OnnxInput[] { });

            return onnxPredictionPipeline.Fit(emptyDv);
        }
    }

The error I get is: System.InvalidOperationException: 'Input shape mismatch: Input 'input_3' has shape 1,5,1, but input data is of length 1.'

Can anyone help me on this input/output? Is there maybe somewhere a ONNX2C# converter or something? ;-)

Thanks in advance!

• Bender