Skip loading external tensors; move constants closer to their users (#21)

<img width="1269" alt="image"
src="https://github.com/justinchuby/model-explorer-onnx/assets/11205048/7a761e95-aa8d-4caa-87c7-461516ddaa8f">

Author: justinchuby

Diff for: src/model_explorer_onnx/main.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import logging
-import os
 from typing import Any, Literal, Sequence
 
 import ml_dtypes
@@ -20,23 +19,23 @@
 def display_tensor(tensor: ir.TensorProtocol | None) -> str:
     if tensor is None:
         return "Data not available"
-    if tensor.size < _TENSOR_DISPLAY_LIMIT:
-        try:
-            array = tensor.numpy()
-            if tensor.dtype == ir.DataType.BFLOAT16:
-                array = array.view(ml_dtypes.bfloat16)
-            elif tensor.dtype == ir.DataType.FLOAT8E4M3FN:
-                array = array.view(ml_dtypes.float8_e4m3fn)
-            elif tensor.dtype == ir.DataType.FLOAT8E4M3FNUZ:
-                array = array.view(ml_dtypes.float8_e4m3fnuz)
-            elif tensor.dtype == ir.DataType.FLOAT8E5M2:
-                array = array.view(ml_dtypes.float8_e5m2)
-            elif tensor.dtype == ir.DataType.FLOAT8E5M2FNUZ:
-                array = array.view(ml_dtypes.float8_e5m2fnuz)
-            return np.array2string(array, separator=",")
-        except Exception as e:
-            logger.warning("Failed to display tensor: %s", e)
-            return str(tensor)
+    if tensor.size > _TENSOR_DISPLAY_LIMIT or isinstance(tensor, ir.ExternalTensor):
+        return str(tensor)
+    try:
+        array = tensor.numpy()
+        if tensor.dtype == ir.DataType.BFLOAT16:
+            array = array.view(ml_dtypes.bfloat16)
+        elif tensor.dtype == ir.DataType.FLOAT8E4M3FN:
+            array = array.view(ml_dtypes.float8_e4m3fn)
+        elif tensor.dtype == ir.DataType.FLOAT8E4M3FNUZ:
+            array = array.view(ml_dtypes.float8_e4m3fnuz)
+        elif tensor.dtype == ir.DataType.FLOAT8E5M2:
+            array = array.view(ml_dtypes.float8_e5m2)
+        elif tensor.dtype == ir.DataType.FLOAT8E5M2FNUZ:
+            array = array.view(ml_dtypes.float8_e5m2fnuz)
+        return np.array2string(array, separator=",")
+    except Exception as e:
+        logger.warning("Failed to display tensor: %s", e)
     return str(tensor)
 
 
@@ -262,9 +261,13 @@ def create_node(
     """
     assert onnx_node.name, "Bug: Node name is required"
 
-    embedded_namespace = parse_namespace(onnx_node.name)
-    if embedded_namespace:
-        namespace = namespace + "/" + "/".join(embedded_namespace)
+    if onnx_node.op_type == "Constant":
+        # Move the constant closer to the user node's namespace
+        namespace = get_constant_namespace(onnx_node.outputs[0], namespace)
+    else:
+        embedded_namespace = parse_namespace(onnx_node.name)
+        if embedded_namespace:
+            namespace = namespace + "/" + "/".join(embedded_namespace)
     node = graph_builder.GraphNode(
         id=onnx_node.name,
         label=create_op_label(onnx_node.domain, onnx_node.op_type),
@@ -312,8 +315,8 @@ def add_graph_io(
         all_nodes[node.id] = node
 
 
-def get_initializer_namespace(initializer: ir.Value, root_namespace: str) -> str:
-    # If the initializer is used by a single node, move it to the same namespace as the node
+def get_constant_namespace(initializer: ir.Value, root_namespace: str) -> str:
+    """Move the constant/initializer closer to the user's namespace."""
     initializer_namespace = root_namespace
     # A single node can have multiple uses of the same value.
     # Here we only count the unique nodes that use the initializer to push the
@@ -323,6 +326,7 @@ def get_initializer_namespace(initializer: ir.Value, root_namespace: str) -> str
         # The initializer is not used by any node. Keep it in the root namespace.
         return initializer_namespace
     if len(user_nodes) == 1:
+        # If the initializer is used by a single node, move it to the same namespace as the node
         user_node = user_nodes[0]
         assert (
             user_node.name
@@ -376,7 +380,7 @@ def add_initializers(
         node = graph_builder.GraphNode(
             id=initializer_node_name,
             label="Initializer",
-            namespace=get_initializer_namespace(initializer, namespace),
+            namespace=get_constant_namespace(initializer, namespace),
         )
         # Add metadata for the output tensor
         if initializer.const_value is None:
@@ -458,24 +462,25 @@ def convert(
     ) -> model_explorer.ModelExplorerGraphs:
         del settings  # Unused
 
+        # Do not load external data because the model file is copied to a temporary location
+        # and the external data paths are not valid anymore.
         onnx_model = onnx.load(model_path, load_external_data=False)
         try:
-            onnx_model = onnx.shape_inference.infer_shapes(onnx_model)
+            onnx_model = onnx.shape_inference.infer_shapes(onnx_model, data_prop=True)
         except Exception as e:
             logger.warning(
                 "Failed to infer shapes. Continue with the original model. Error: %s", e
             )
 
-        # Load external data after shape inference
-        model_filepath = os.path.abspath(model_path)
-        base_dir = os.path.dirname(model_filepath)
-        onnx.load_external_data_for_model(onnx_model, base_dir)
-
         # Convert to ONNX IR
         model = ir.serde.deserialize_model(onnx_model)
         all_function_ids = set(model.functions)
         graphs = []
-        opset_version = model.opset_imports.get("", _DEFAULT_OPSET_VERSION)
+        opset_version = model.opset_imports.get("")
+        if opset_version is None:
+            opset_version = model.opset_imports.get("ai.onnx")
+        if opset_version is None:
+            opset_version = _DEFAULT_OPSET_VERSION
         # TODO: Better support subgraphs in nodes
         main_graph = create_graph(
             model.graph, all_function_ids, opset_version=opset_version