[onnx] IR_version <4 : Export Issue

Problem

InstanceNormalization export test fails because in ONNX IR version < 4, the initializers must be a subset of graph inputs.

Error: Running pytest test_onnx_nodes_export.py -k "instancenorm" with onnx-1.16.2/../../test_instancenorm_example/model.onnx produces:

[NOTICE] - The ONNX file is invalid:
[NOTICE]   bias_out0 in initializer but not in graph input
[NOTICE]   s_out0 in initializer but not in graph input

Evidence: According to the ONNX model proto documentation (line 71):

// IR VERSION 4 published on Jan 22, 2019
// - Relax constraint that initializers should be a subset of graph inputs

Proposed Fix

Ensure that initializers are also included as inputs when ir_version < 4 in test_onnx_nodes_export.py.

Files

• test_onnx_nodes_export.py
• onnx_export.py