ONNX Runtime ONNXRuntimeError: [ONNXRuntimeError] : 38 : FAIL : Invalid model output

What is ONNX Runtime ONNXRuntimeError: [ONNXRuntimeError] : 38 : FAIL : Invalid model output

Understanding ONNX Runtime

ONNX Runtime is a high-performance inference engine for machine learning models in the Open Neural Network Exchange (ONNX) format. It is designed to optimize and accelerate the deployment of machine learning models across various platforms and devices. By providing a consistent API, ONNX Runtime allows developers to run models trained in different frameworks like PyTorch, TensorFlow, and others, ensuring interoperability and flexibility in model deployment.

Identifying the Symptom

When working with ONNX Runtime, you might encounter the following error message: ONNXRuntimeError: [ONNXRuntimeError] : 38 : FAIL : Invalid model output. This error indicates that there is an issue with the output generated by the model during inference.

What You Observe

Upon running inference using ONNX Runtime, the process fails, and the above error message is displayed. This typically halts the execution and prevents obtaining the expected results from the model.

Exploring the Issue

The error ONNXRuntimeError: [ONNXRuntimeError] : 38 : FAIL : Invalid model output suggests that the output produced by the model does not conform to the expected format or structure. This can occur due to several reasons, such as:

The model's output node is not correctly defined.The output data type or shape does not match the expected configuration.There is a mismatch between the model's output and the data processing pipeline.

Understanding Error Code 38

Error code 38 in ONNX Runtime typically relates to failures in processing the model's output. It is crucial to ensure that the model's output is well-defined and aligns with the expected output specifications.

Steps to Resolve the Issue

To address the Invalid model output error, follow these steps:

1. Verify Model Output Configuration

Ensure that the model's output node is correctly specified in the ONNX model file. You can inspect the model using tools like Netron to visualize the model architecture and verify the output node configuration.

2. Check Output Data Type and Shape

Confirm that the data type and shape of the model's output match the expected configuration. You can use the ONNX Runtime API to inspect the model's output details:

import onnxruntime as ort# Load the modelsession = ort.InferenceSession('model.onnx')# Get output detailsoutput_details = session.get_outputs()for output in output_details: print(f"Output name: {output.name}, type: {output.type}, shape: {output.shape}")

3. Align Output with Data Processing Pipeline

Ensure that the model's output is compatible with the subsequent data processing steps. Adjust the data processing pipeline to accommodate the model's output format if necessary.

4. Validate Model with Test Inputs

Use test inputs to validate the model's output. This helps in identifying discrepancies between the expected and actual output. You can use sample data to run inference and compare the results:

# Example inferenceinput_data = {"input_name": test_input}outputs = session.run(None, input_data)print(outputs)

Additional Resources

For more information on ONNX Runtime and troubleshooting, consider visiting the following resources:

ONNX Runtime Official WebsiteONNX Runtime GitHub RepositoryONNX Official Website

By following these steps, you should be able to resolve the Invalid model output error and ensure that your ONNX model runs smoothly with ONNX Runtime.