[Model Optimizer] Add rule to remove Resize nodes with unity Resize scale (s=1's)

Author: reesegrimsley

scripts/osrt_model_tools/onnx_tools/tidl-onnx-model-optimizer/tidl_onnx_model_optimizer/src/resize.py

@@ -63,6 +63,7 @@
 import onnx_graphsurgeon as gs
 import onnx
 import numpy as np
+from tidl_onnx_model_optimizer.src.common import find_out_layers, remove_node
 
 
 def tidl_convert_resize_params_size_to_scale(graph: gs.Graph,
@@ -102,3 +103,42 @@ def tidl_convert_resize_params_size_to_scale(graph: gs.Graph,
             # endif
         # endif
     # endfor
+
+
+def tidl_remove_unity_resize(graph: gs.Graph,
+                            onnx_graph: onnx.GraphProto):
+    '''
+    Some models have an effectively null resize node that scales by a factor of 1 in all dimensions
+    Such a node is often an export artifact -- a layer added by a model format converter
+    This is node effectively unity, but it will be processed nonetheless. It should therefore be removed
+    '''
+
+    tensors = graph.tensors()
+    nodes_to_remove = []
+    for node in graph.nodes:
+
+        if node.op == "Resize":
+            inputs = node.inputs
+            if len(inputs) >= 3:
+                X, roi, scales = inputs[0:3]
+            else: 
+                continue
+            Y = node.outputs[0]
+            attrs = node.attrs
+
+            if X.shape == Y.shape and all(map(lambda x: x==1, scales.values)):
+                #ensure it's not using ROI, which is only with crop-and-resize mode
+                if node.attrs['coordinate_transformation_mode'] == 'tf_crop_and_resize':
+                    logging.warning("Detected Resize node as using ROI... skipping")
+                    continue
+
+                logging.debug("Removing unity Resize node %s" % node.name)
+            
+                out_nodes = find_out_layers(node)
+
+                for o_node in out_nodes:
+                    for i, net in enumerate(o_node.inputs):
+                        if net == Y:
+                            o_node.inputs[i] = X
+
+                #node will be removed by cleanup since it has only unused outputs