NXP backend: Add MobileNetV2 example model and test (#12892)

### Summary
Add MobileNetV2 model as example and for integration testing

### Test plan
Support for testing full conversion on this model is included in
`run_aot_example.sh`.

---------

Co-authored-by: Lukas Sztefek <[email protected]>

Author: StrycekSimon

.github/workflows/pull.yml

@@ -860,8 +860,9 @@ jobs:
         # Run pytest
         PYTHON_EXECUTABLE=python bash backends/nxp/run_unittests.sh
 
-        # Run aot example:
-        PYTHON_EXECUTABLE=python bash examples/nxp/run_aot_example.sh
+        # Run aot examples:
+        PYTHON_EXECUTABLE=python bash examples/nxp/run_aot_example.sh cifar10        
+        PYTHON_EXECUTABLE=python bash examples/nxp/run_aot_example.sh mobilenetv2
 
 
   test-vulkan-models-linux:

backends/nxp/tests/executors.py

@@ -57,6 +57,13 @@ def inference(
             return output.detach().numpy()
         elif isinstance(output, tuple) and len(output) == 1:
             return output[0].detach().numpy()
+        elif isinstance(output, tuple):
+            output_names = self.edge_program.graph_signature.user_outputs
+
+            return {
+                name: tensor.detach().numpy()
+                for (name, tensor) in zip(output_names, output)
+            }
 
         raise RuntimeError(
             "Edge program inference with multiple outputs not implemented"

examples/nxp/aot_neutron_compile.py

@@ -37,6 +37,8 @@
 
 from .experimental.cifar_net.cifar_net import CifarNet, test_cifarnet_model
 
+from .models.mobilenet_v2 import MobilenetV2
+
 FORMAT = "[%(levelname)s %(asctime)s %(filename)s:%(lineno)s] %(message)s"
 logging.basicConfig(level=logging.INFO, format=FORMAT)
 
@@ -87,7 +89,7 @@ def get_model_and_inputs_from_name(model_name: str):
         logging.warning(
             "Using a model from examples/models not all of these are currently supported"
         )
-        model, example_inputs, _ = EagerModelFactory.create_model(
+        model, example_inputs, _, _ = EagerModelFactory.create_model(
             *MODEL_NAME_TO_MODEL[model_name]
         )
     else:
@@ -100,6 +102,7 @@ def get_model_and_inputs_from_name(model_name: str):
 
 models = {
     "cifar10": CifarNet,
+    "mobilenetv2": MobilenetV2,
 }
 
 

examples/nxp/models/mobilenet_v2.py

@@ -0,0 +1,114 @@
+# Copyright 2025 NXP
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+import itertools
+from typing import Iterator
+
+import torch
+import torchvision
+
+from executorch.examples.models.mobilenet_v2 import MV2Model
+from torch.utils.data import DataLoader
+from torchvision import transforms
+
+
+class MobilenetV2(MV2Model):
+
+    def get_calibration_inputs(
+        self, batch_size: int = 1
+    ) -> Iterator[tuple[torch.Tensor]]:
+        """
+        Returns an iterator for the Imagenette validation dataset, downloading it if necessary.
+
+        Args:
+            batch_size (int): The batch size for the iterator.
+
+        Returns:
+            iterator: An iterator that yields batches of images from the Imagnetette validation dataset.
+        """
+        dataloader = self.get_dataset(batch_size)
+
+        # Return the iterator
+        dataloader_iterable = itertools.starmap(
+            lambda data, label: (data,), iter(dataloader)
+        )
+
+        # We want approximately 500 samples
+        batch_count = 500 // batch_size
+        return itertools.islice(dataloader_iterable, batch_count)
+
+    def get_dataset(self, batch_size):
+        # Define data transformations
+        data_transforms = transforms.Compose(
+            [
+                transforms.Resize((224, 224)),
+                transforms.ToTensor(),
+                transforms.Normalize(
+                    mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]
+                ),  # ImageNet stats
+            ]
+        )
+
+        dataset = torchvision.datasets.Imagenette(
+            root="./data", split="val", transform=data_transforms, download=True
+        )
+        dataloader = torch.utils.data.DataLoader(
+            dataset,
+            batch_size=batch_size,
+            shuffle=False,
+            num_workers=1,
+        )
+        return dataloader
+
+
+def gather_samples_per_class_from_dataloader(
+    dataloader, num_samples_per_class=10
+) -> list[tuple]:
+    """
+    Gathers a specified number of samples for each class from a DataLoader.
+
+    Args:
+        dataloader (DataLoader): The PyTorch DataLoader object.
+        num_samples_per_class (int): The number of samples to gather for each class. Defaults to 10.
+
+    Returns:
+        samples: A list of (sample, label) tuples.
+    """
+
+    if not isinstance(dataloader, DataLoader):
+        raise TypeError("dataloader must be a torch.utils.data.DataLoader object")
+    if not isinstance(num_samples_per_class, int) or num_samples_per_class <= 0:
+        raise ValueError("num_samples_per_class must be a positive integer")
+
+    labels = sorted(
+        set([label for _, label in dataloader.dataset])
+    )  # Get unique labels from the dataset
+    samples_per_label = {label: [] for label in labels}  # Initialize dictionary
+
+    for sample, label in dataloader:
+        label = label.item()
+        if len(samples_per_label[label]) < num_samples_per_class:
+            samples_per_label[label].append((sample, label))
+
+    samples = []
+
+    for label in labels:
+        samples.extend(samples_per_label[label])
+
+    return samples
+
+
+def generate_input_samples_file():
+    model = MobilenetV2()
+    dataloader = model.get_dataset(batch_size=1)
+    samples = gather_samples_per_class_from_dataloader(
+        dataloader, num_samples_per_class=2
+    )
+
+    torch.save(samples, "calibration_data.pt")
+
+
+if __name__ == "__main__":
+    generate_input_samples_file()

examples/nxp/run_aot_example.sh

@@ -7,11 +7,12 @@ set -eux
 
 SCRIPT_DIR=$(dirname $(readlink -fm $0))
 EXECUTORCH_DIR=$(dirname $(dirname $SCRIPT_DIR))
+MODEL=${1:-"cifar10"}
 
 cd $EXECUTORCH_DIR
 
 # Run the AoT example
 python -m examples.nxp.aot_neutron_compile --quantize \
-    --delegate --neutron_converter_flavor SDK_25_03 -m cifar10
+    --delegate --neutron_converter_flavor SDK_25_03 -m ${MODEL}
 # verify file exists
-test -f cifar10_nxp_delegate.pte
+test -f ${MODEL}_nxp_delegate.pte