From 40f257ee57c4a5c35e2ca9aace67026ba4a54e57 Mon Sep 17 00:00:00 2001
From: Charles Beauville <charles@flower.ai>
Date: Fri, 5 Apr 2024 15:56:36 +0200
Subject: [PATCH 1/2] Initial draft

---
 examples/quickstart-pytorch/README.md |  8 ++-
 examples/quickstart-pytorch/client.py | 70 ++++++++++++++++-----------
 2 files changed, 49 insertions(+), 29 deletions(-)

diff --git a/examples/quickstart-pytorch/README.md b/examples/quickstart-pytorch/README.md
index 978191cc0ecd..03ac96190622 100644
--- a/examples/quickstart-pytorch/README.md
+++ b/examples/quickstart-pytorch/README.md
@@ -90,7 +90,13 @@ flower-superlink --insecure
 Start 2 Flower `SuperNodes` in 2 separate terminal windows, using:
 
 ```bash
-flower-client-app client:app --insecure
+flower-client-app client:partition_0 --insecure
+```
+
+And:
+
+```bash
+flower-client-app client:partition_1 --insecure
 ```
 
 ### 3. Run the Flower App
diff --git a/examples/quickstart-pytorch/client.py b/examples/quickstart-pytorch/client.py
index be4be88b8f8d..c25fb8a15216 100644
--- a/examples/quickstart-pytorch/client.py
+++ b/examples/quickstart-pytorch/client.py
@@ -94,59 +94,73 @@ def apply_transforms(batch):
 # 2. Federation of the pipeline with Flower
 # #############################################################################
 
-# Get partition id
-parser = argparse.ArgumentParser(description="Flower")
-parser.add_argument(
-    "--partition-id",
-    choices=[0, 1, 2],
-    default=0,
-    type=int,
-    help="Partition of the dataset divided into 3 iid partitions created artificially.",
-)
-partition_id = parser.parse_known_args()[0].partition_id
-
-# Load model and data (simple CNN, CIFAR-10)
-net = Net().to(DEVICE)
-trainloader, testloader = load_data(partition_id=partition_id)
-
 
 # Define Flower client
 class FlowerClient(NumPyClient):
+    def __init__(self, net, data):
+        super().__init__()
+        self.net = net
+        self.trainloader, self.testloader = data
+
     def get_parameters(self, config):
-        return [val.cpu().numpy() for _, val in net.state_dict().items()]
+        return [val.cpu().numpy() for _, val in self.net.state_dict().items()]
 
     def set_parameters(self, parameters):
-        params_dict = zip(net.state_dict().keys(), parameters)
+        params_dict = zip(self.net.state_dict().keys(), parameters)
         state_dict = OrderedDict({k: torch.tensor(v) for k, v in params_dict})
-        net.load_state_dict(state_dict, strict=True)
+        self.net.load_state_dict(state_dict, strict=True)
 
     def fit(self, parameters, config):
         self.set_parameters(parameters)
-        train(net, trainloader, epochs=1)
-        return self.get_parameters(config={}), len(trainloader.dataset), {}
+        train(self.net, self.trainloader, epochs=1)
+        return self.get_parameters(config={}), len(self.trainloader.dataset), {}
 
     def evaluate(self, parameters, config):
         self.set_parameters(parameters)
-        loss, accuracy = test(net, testloader)
-        return loss, len(testloader.dataset), {"accuracy": accuracy}
+        loss, accuracy = test(self.net, self.testloader)
+        return loss, len(self.testloader.dataset), {"accuracy": accuracy}
+
 
+def get_client_fn(partition_id):
+    net = Net().to(DEVICE)
+    data = load_data(partition_id=partition_id)
 
-def client_fn(cid: str):
-    """Create and return an instance of Flower `Client`."""
-    return FlowerClient().to_client()
+    def client_fn(cid: str):
+        """Create and return an instance of Flower `Client`."""
+        return FlowerClient(net, data).to_client()
+
+    return client_fn
 
 
 # Flower ClientApp
-app = ClientApp(
-    client_fn=client_fn,
+partition_0 = ClientApp(
+    client_fn=get_client_fn(0),
 )
 
+partition_1 = ClientApp(
+    client_fn=get_client_fn(0),
+)
 
 # Legacy mode
 if __name__ == "__main__":
     from flwr.client import start_client
 
+    # Get partition id
+    parser = argparse.ArgumentParser(description="Flower")
+    parser.add_argument(
+        "--partition-id",
+        choices=[0, 1, 2],
+        default=0,
+        type=int,
+        help="Partition of the dataset divided into 3 iid partitions created artificially.",
+    )
+    partition_id = parser.parse_known_args()[0].partition_id
+
+    # Load model and data (simple CNN, CIFAR-10)
+    net = Net().to(DEVICE)
+    data = load_data(partition_id=partition_id)
+
     start_client(
         server_address="127.0.0.1:8080",
-        client=FlowerClient().to_client(),
+        client=FlowerClient(net, data).to_client(),
     )

From 745739c16a82e85a60fd097344ec95f411a59617 Mon Sep 17 00:00:00 2001
From: Charles Beauville <charles@flower.ai>
Date: Fri, 5 Apr 2024 16:00:28 +0200
Subject: [PATCH 2/2] Use correct partition

---
 examples/quickstart-pytorch/client.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/quickstart-pytorch/client.py b/examples/quickstart-pytorch/client.py
index c25fb8a15216..9cf7da469b41 100644
--- a/examples/quickstart-pytorch/client.py
+++ b/examples/quickstart-pytorch/client.py
@@ -138,7 +138,7 @@ def client_fn(cid: str):
 )
 
 partition_1 = ClientApp(
-    client_fn=get_client_fn(0),
+    client_fn=get_client_fn(1),
 )
 
 # Legacy mode