Fix federated learning demos and tests (#9488)

demo/nvflare/vertical/README.md

@@ -6,7 +6,7 @@ This directory contains a demo of Vertical Federated Learning using
 ## Training with CPU only
 
 To run the demo, first build XGBoost with the federated learning plugin enabled (see the
-[README](../../plugin/federated/README.md)).
+[README](../../../plugin/federated/README.md)).
 
 Install NVFlare (note that currently NVFlare only supports Python 3.8):
 ```shell

demo/nvflare/vertical/custom/trainer.py

@@ -16,7 +16,7 @@ class SupportedTasks(object):
 
 class XGBoostTrainer(Executor):
     def __init__(self, server_address: str, world_size: int, server_cert_path: str,
-                 client_key_path: str, client_cert_path: str):
+                 client_key_path: str, client_cert_path: str, use_gpus: bool):
         """Trainer for federated XGBoost.
 
         Args:
@@ -32,6 +32,7 @@ class XGBoostTrainer(Executor):
         self._server_cert_path = server_cert_path
         self._client_key_path = client_key_path
         self._client_cert_path = client_cert_path
+        self._use_gpus = use_gpus
 
     def execute(self, task_name: str, shareable: Shareable, fl_ctx: FLContext,
                 abort_signal: Signal) -> Shareable:
@@ -81,6 +82,8 @@ class XGBoostTrainer(Executor):
                 'objective': 'binary:logistic',
                 'eval_metric': 'auc',
             }
+            if self._use_gpus:
+                self.log_info(fl_ctx, 'GPUs are not currently supported by vertical federated XGBoost')
 
             # specify validations set to watch performance
             watchlist = [(dtest, "eval"), (dtrain, "train")]

demo/nvflare/vertical/prepare_data.sh

@@ -56,7 +56,7 @@ fi
 
 nvflare poc -n 2 --prepare
 mkdir -p /tmp/nvflare/poc/admin/transfer/vertical-xgboost
-cp -fr config custom /tmp/nvflare/poc/admin/transfer/vertical-xgboost
+cp -fr ../config custom /tmp/nvflare/poc/admin/transfer/vertical-xgboost
 cp server-*.pem client-cert.pem /tmp/nvflare/poc/server/
 for (( site=1; site<=world_size; site++ )); do
   cp server-cert.pem client-*.pem /tmp/nvflare/poc/site-"${site}"/