Migrate vivit tutorial to Keras3-all backends (#1739)

examples/vision/ipynb/vivit.ipynb

@@ -10,7 +10,7 @@
     "\n",
     "**Author:** [Aritra Roy Gosthipaty](https://twitter.com/ariG23498), [Ayush Thakur](https://twitter.com/ayushthakur0) (equal contribution)<br>\n",
     "**Date created:** 2022/01/12<br>\n",
-    "**Last modified:**  2024/01/13<br>\n",
+    "**Last modified:**  2024/01/15<br>\n",
     "**Description:** A Transformer-based architecture for video classification."
    ]
   },
@@ -43,8 +43,8 @@
     "the embedding scheme and one of the variants of the Transformer\n",
     "architecture, for simplicity.\n",
     "\n",
-    "This example requires the `medmnist`\n",
-    "package, which can be installed by running the code cell below."
+    "This example requires  `medmnist` package, which can be installed\n",
+    "by running the code cell below."
    ]
   },
   {
@@ -81,11 +81,9 @@
     "import medmnist\n",
     "import ipywidgets\n",
     "import numpy as np\n",
-    "\n",
+    "import tensorflow as tf  # for data preprocessing only\n",
     "import keras\n",
-    "import tensorflow as tf\n",
-    "from keras import layers\n",
-    "from keras import ops\n",
+    "from keras import layers, ops\n",
     "\n",
     "# Setting seed for reproducibility\n",
     "SEED = 42\n",
@@ -214,15 +212,17 @@
    "outputs": [],
    "source": [
     "\n",
-    "def preprocess(frames, label):\n",
+    "def preprocess(frames: tf.Tensor, label: tf.Tensor):\n",
     "    \"\"\"Preprocess the frames tensors and parse the labels.\"\"\"\n",
     "    # Preprocess images\n",
-    "    frames = ops.cast(frames, \"float32\")\n",
-    "    frames = ops.expand_dims(\n",
-    "        frames, axis=-1\n",
-    "    )  # The new axis is to help for further processing with Conv3D layers\n",
+    "    frames = tf.image.convert_image_dtype(\n",
+    "        frames[\n",
+    "            ..., tf.newaxis\n",
+    "        ],  # The new axis is to help for further processing with Conv3D layers\n",
+    "        tf.float32,\n",
+    "    )\n",
     "    # Parse label\n",
-    "    label = ops.cast(label, \"float32\")\n",
+    "    label = tf.cast(label, tf.float32)\n",
     "    return frames, label\n",
     "\n",
     "\n",
@@ -337,7 +337,7 @@
     "        self.position_embedding = layers.Embedding(\n",
     "            input_dim=num_tokens, output_dim=self.embed_dim\n",
     "        )\n",
-    "        self.positions = ops.arange(start=0, stop=num_tokens, step=1)\n",
+    "        self.positions = ops.arange(0, num_tokens, 1)\n",
     "\n",
     "    def call(self, encoded_tokens):\n",
     "        # Encode the positions and add it to the encoded tokens\n",
@@ -411,8 +411,8 @@
     "        x3 = layers.LayerNormalization(epsilon=1e-6)(x2)\n",
     "        x3 = keras.Sequential(\n",
     "            [\n",
-    "                layers.Dense(units=embed_dim * 4, activation=\"gelu\"),\n",
-    "                layers.Dense(units=embed_dim, activation=\"gelu\"),\n",
+    "                layers.Dense(units=embed_dim * 4, activation=ops.gelu),\n",
+    "                layers.Dense(units=embed_dim, activation=ops.gelu),\n",
     "            ]\n",
     "        )(x3)\n",
     "\n",
@@ -511,9 +511,9 @@
     "\n",
     "for i, (testsample, label) in enumerate(zip(testsamples, labels)):\n",
     "    # Generate gif\n",
-    "    testsample = ops.reshape(testsample, (-1, 28, 28))\n",
+    "    testsample = np.reshape(testsample.numpy(), (-1, 28, 28))\n",
     "    with io.BytesIO() as gif:\n",
-    "        imageio.mimsave(gif, (testsample.numpy() * 255).astype(\"uint8\"), \"GIF\", fps=5)\n",
+    "        imageio.mimsave(gif, (testsample * 255).astype(\"uint8\"), \"GIF\", fps=5)\n",
     "        videos.append(gif.getvalue())\n",
     "\n",
     "    # Get model prediction\n",