fix hello_world tf result printing (#2910)

Author: SYangster

examples/hello-world/hello_world.ipynb

@@ -559,21 +559,30 @@
    },
    "outputs": [],
    "source": [
-    "from nvflare.fuel.utils import fobs\n",
-    "from nvflare.app_common.decomposers import common_decomposers\n",
     "import pprint\n",
-    "\n",
-    "# This example stores numpy arrays in FOBS format. Decomposers for Numpy is not registered automatically.\n",
-    "common_decomposers.register()\n",
+    "from nvflare.app_opt.tf.utils import flat_layer_weights_dict\n",
+    "from tensorflow.keras import layers, models\n",
     "\n",
     "result = sess.download_job_result(job_id)\n",
-    "with open(result + \"/workspace/app_server/tf_model.weights.h5\", \"rb\") as f:\n",
-    "    bytes = f.read()\n",
     "\n",
-    "weights = fobs.loads(bytes)\n",
+    "class Net(models.Sequential):\n",
+    "    def __init__(self, input_shape=(None, 28, 28)):\n",
+    "        super().__init__()\n",
+    "        self._input_shape = input_shape\n",
+    "        self.add(layers.Flatten())\n",
+    "        self.add(layers.Dense(128, activation=\"relu\"))\n",
+    "        self.add(layers.Dropout(0.2))\n",
+    "        self.add(layers.Dense(10))\n",
+    "\n",
+    "model = Net()\n",
+    "model.build(input_shape=(None, 28, 28))\n",
+    "model.load_weights(result + \"/workspace/app_server/tf_model.weights.h5\")\n",
+    "model.summary()\n",
+    "\n",
+    "layer_weights_dict = flat_layer_weights_dict({layer.name: layer.get_weights() for layer in model.layers})\n",
     "\n",
     "pp = pprint.PrettyPrinter(indent=4)\n",
-    "pp.pprint(weights)"
+    "pp.pprint(layer_weights_dict)"
    ]
   },
   {
@@ -872,19 +881,30 @@
    },
    "outputs": [],
    "source": [
-    "from nvflare.fuel.utils import fobs\n",
-    "from nvflare.app_common.decomposers import common_decomposers\n",
     "import pprint\n",
+    "from nvflare.app_opt.tf.utils import flat_layer_weights_dict\n",
+    "from tensorflow.keras import layers, models\n",
     "\n",
-    "common_decomposers.register()\n",
     "result = sess.download_job_result(job_id)\n",
-    "with open(result + \"/workspace/app_server/tf_model.weights.h5\", \"rb\") as f:\n",
-    "    bytes = f.read()\n",
     "\n",
-    "weights = fobs.loads(bytes)\n",
+    "class Net(models.Sequential):\n",
+    "    def __init__(self, input_shape=(None, 28, 28)):\n",
+    "        super().__init__()\n",
+    "        self._input_shape = input_shape\n",
+    "        self.add(layers.Flatten())\n",
+    "        self.add(layers.Dense(128, activation=\"relu\"))\n",
+    "        self.add(layers.Dropout(0.2))\n",
+    "        self.add(layers.Dense(10))\n",
+    "\n",
+    "model = Net()\n",
+    "model.build(input_shape=(None, 28, 28))\n",
+    "model.load_weights(result + \"/workspace/app_server/tf_model.weights.h5\")\n",
+    "model.summary()\n",
+    "\n",
+    "layer_weights_dict = flat_layer_weights_dict({layer.name: layer.get_weights() for layer in model.layers})\n",
     "\n",
     "pp = pprint.PrettyPrinter(indent=4)\n",
-    "pp.pprint(weights)"
+    "pp.pprint(layer_weights_dict)"
    ]
   },
   {