lightning/notebooks/02-datamodules.ipynb

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{
"cells": [
{
"cell_type": "markdown",
"metadata": {
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"source": [
"<a href=\"https://colab.research.google.com/github/PytorchLightning/pytorch-lightning/blob/master/notebooks/02-datamodules.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
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},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "2O5r7QvP8-rt"
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"source": [
"# PyTorch Lightning DataModules ⚡\n",
"\n",
"With the release of `pytorch-lightning` version 0.9.0, we have included a new class called `LightningDataModule` to help you decouple data related hooks from your `LightningModule`.\n",
"\n",
"This notebook will walk you through how to start using Datamodules.\n",
"\n",
"The most up to date documentation on datamodules can be found [here](https://pytorch-lightning.readthedocs.io/en/latest/extensions/datamodules.html).\n",
"\n",
"---\n",
"\n",
" - Give us a ⭐ [on Github](https://www.github.com/PytorchLightning/pytorch-lightning/)\n",
" - Check out [the documentation](https://pytorch-lightning.readthedocs.io/en/latest/)\n",
" - Join us [on Slack](https://join.slack.com/t/pytorch-lightning/shared_invite/zt-f6bl2l0l-JYMK3tbAgAmGRrlNr00f1A)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "6RYMhmfA9ATN"
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"source": [
"### Setup\n",
"Lightning is easy to install. Simply ```pip install pytorch-lightning```"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "lj2zD-wsbvGr"
},
"outputs": [],
"source": [
"! pip install pytorch-lightning --quiet"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "8g2mbvy-9xDI"
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"source": [
"# Introduction\n",
"\n",
"First, we'll go over a regular `LightningModule` implementation without the use of a `LightningDataModule`"
]
},
{
"cell_type": "code",
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"source": [
"import pytorch_lightning as pl\n",
"from pytorch_lightning.metrics.functional import accuracy\n",
"import torch\n",
"from torch import nn\n",
"import torch.nn.functional as F\n",
"from torch.utils.data import random_split, DataLoader\n",
"\n",
"# Note - you must have torchvision installed for this example\n",
"from torchvision.datasets import MNIST, CIFAR10\n",
"from torchvision import transforms"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "DzgY7wi88UuG"
},
"source": [
"## Defining the LitMNISTModel\n",
"\n",
"Below, we reuse a `LightningModule` from our hello world tutorial that classifies MNIST Handwritten Digits.\n",
"\n",
"Unfortunately, we have hardcoded dataset-specific items within the model, forever limiting it to working with MNIST Data. 😢\n",
"\n",
"This is fine if you don't plan on training/evaluating your model on different datasets. However, in many cases, this can become bothersome when you want to try out your architecture with different datasets."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "IQkW8_FF5nU2"
},
"outputs": [],
"source": [
"class LitMNIST(pl.LightningModule):\n",
" \n",
" def __init__(self, data_dir='./', hidden_size=64, learning_rate=2e-4):\n",
"\n",
" super().__init__()\n",
"\n",
" # We hardcode dataset specific stuff here.\n",
" self.data_dir = data_dir\n",
" self.num_classes = 10\n",
" self.dims = (1, 28, 28)\n",
" channels, width, height = self.dims\n",
" self.transform = transforms.Compose([\n",
" transforms.ToTensor(),\n",
" transforms.Normalize((0.1307,), (0.3081,))\n",
" ])\n",
"\n",
" self.hidden_size = hidden_size\n",
" self.learning_rate = learning_rate\n",
"\n",
" # Build model\n",
" self.model = nn.Sequential(\n",
" nn.Flatten(),\n",
" nn.Linear(channels * width * height, hidden_size),\n",
" nn.ReLU(),\n",
" nn.Dropout(0.1),\n",
" nn.Linear(hidden_size, hidden_size),\n",
" nn.ReLU(),\n",
" nn.Dropout(0.1),\n",
" nn.Linear(hidden_size, self.num_classes)\n",
" )\n",
"\n",
" def forward(self, x):\n",
" x = self.model(x)\n",
" return F.log_softmax(x, dim=1)\n",
"\n",
" def training_step(self, batch, batch_idx):\n",
" x, y = batch\n",
" logits = self(x)\n",
" loss = F.nll_loss(logits, y)\n",
" return loss\n",
"\n",
" def validation_step(self, batch, batch_idx):\n",
" x, y = batch\n",
" logits = self(x)\n",
" loss = F.nll_loss(logits, y)\n",
" preds = torch.argmax(logits, dim=1)\n",
" acc = accuracy(preds, y)\n",
" self.log('val_loss', loss, prog_bar=True)\n",
" self.log('val_acc', acc, prog_bar=True)\n",
" return loss\n",
"\n",
" def configure_optimizers(self):\n",
" optimizer = torch.optim.Adam(self.parameters(), lr=self.learning_rate)\n",
" return optimizer\n",
"\n",
" ####################\n",
" # DATA RELATED HOOKS\n",
" ####################\n",
"\n",
" def prepare_data(self):\n",
" # download\n",
" MNIST(self.data_dir, train=True, download=True)\n",
" MNIST(self.data_dir, train=False, download=True)\n",
"\n",
" def setup(self, stage=None):\n",
"\n",
" # Assign train/val datasets for use in dataloaders\n",
" if stage == 'fit' or stage is None:\n",
" mnist_full = MNIST(self.data_dir, train=True, transform=self.transform)\n",
" self.mnist_train, self.mnist_val = random_split(mnist_full, [55000, 5000])\n",
"\n",
" # Assign test dataset for use in dataloader(s)\n",
" if stage == 'test' or stage is None:\n",
" self.mnist_test = MNIST(self.data_dir, train=False, transform=self.transform)\n",
"\n",
" def train_dataloader(self):\n",
" return DataLoader(self.mnist_train, batch_size=32)\n",
"\n",
" def val_dataloader(self):\n",
" return DataLoader(self.mnist_val, batch_size=32)\n",
"\n",
" def test_dataloader(self):\n",
" return DataLoader(self.mnist_test, batch_size=32)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "K7sg9KQd-QIO"
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"source": [
"## Training the ListMNIST Model"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "QxDNDaus6byD"
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"outputs": [],
"source": [
"model = LitMNIST()\n",
"trainer = pl.Trainer(max_epochs=2, gpus=1, progress_bar_refresh_rate=20)\n",
"trainer.fit(model)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "dY8d6GxmB0YU"
},
"source": [
"# Using DataModules\n",
"\n",
"DataModules are a way of decoupling data-related hooks from the `LightningModule` so you can develop dataset agnostic models."
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "eJeT5bW081wn"
},
"source": [
"## Defining The MNISTDataModule\n",
"\n",
"Let's go over each function in the class below and talk about what they're doing:\n",
"\n",
"1. ```__init__```\n",
" - Takes in a `data_dir` arg that points to where you have downloaded/wish to download the MNIST dataset.\n",
" - Defines a transform that will be applied across train, val, and test dataset splits.\n",
" - Defines default `self.dims`, which is a tuple returned from `datamodule.size()` that can help you initialize models.\n",
"\n",
"\n",
"2. ```prepare_data```\n",
" - This is where we can download the dataset. We point to our desired dataset and ask torchvision's `MNIST` dataset class to download if the dataset isn't found there.\n",
" - **Note we do not make any state assignments in this function** (i.e. `self.something = ...`)\n",
"\n",
"3. ```setup```\n",
" - Loads in data from file and prepares PyTorch tensor datasets for each split (train, val, test). \n",
" - Setup expects a 'stage' arg which is used to separate logic for 'fit' and 'test'.\n",
" - If you don't mind loading all your datasets at once, you can set up a condition to allow for both 'fit' related setup and 'test' related setup to run whenever `None` is passed to `stage`.\n",
" - **Note this runs across all GPUs and it *is* safe to make state assignments here**\n",
"\n",
"\n",
"4. ```x_dataloader```\n",
" - `train_dataloader()`, `val_dataloader()`, and `test_dataloader()` all return PyTorch `DataLoader` instances that are created by wrapping their respective datasets that we prepared in `setup()`"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "DfGKyGwG_X9v"
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"outputs": [],
"source": [
"class MNISTDataModule(pl.LightningDataModule):\n",
"\n",
" def __init__(self, data_dir: str = './'):\n",
" super().__init__()\n",
" self.data_dir = data_dir\n",
" self.transform = transforms.Compose([\n",
" transforms.ToTensor(),\n",
" transforms.Normalize((0.1307,), (0.3081,))\n",
" ])\n",
"\n",
" # self.dims is returned when you call dm.size()\n",
" # Setting default dims here because we know them.\n",
" # Could optionally be assigned dynamically in dm.setup()\n",
" self.dims = (1, 28, 28)\n",
" self.num_classes = 10\n",
"\n",
" def prepare_data(self):\n",
" # download\n",
" MNIST(self.data_dir, train=True, download=True)\n",
" MNIST(self.data_dir, train=False, download=True)\n",
"\n",
" def setup(self, stage=None):\n",
"\n",
" # Assign train/val datasets for use in dataloaders\n",
" if stage == 'fit' or stage is None:\n",
" mnist_full = MNIST(self.data_dir, train=True, transform=self.transform)\n",
" self.mnist_train, self.mnist_val = random_split(mnist_full, [55000, 5000])\n",
"\n",
" # Assign test dataset for use in dataloader(s)\n",
" if stage == 'test' or stage is None:\n",
" self.mnist_test = MNIST(self.data_dir, train=False, transform=self.transform)\n",
"\n",
" def train_dataloader(self):\n",
" return DataLoader(self.mnist_train, batch_size=32)\n",
"\n",
" def val_dataloader(self):\n",
" return DataLoader(self.mnist_val, batch_size=32)\n",
"\n",
" def test_dataloader(self):\n",
" return DataLoader(self.mnist_test, batch_size=32)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "H2Yoj-9M9dS7"
},
"source": [
"## Defining the dataset agnostic `LitModel`\n",
"\n",
"Below, we define the same model as the `LitMNIST` model we made earlier. \n",
"\n",
"However, this time our model has the freedom to use any input data that we'd like 🔥."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "PM2IISuOBDIu"
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"outputs": [],
"source": [
"class LitModel(pl.LightningModule):\n",
" \n",
" def __init__(self, channels, width, height, num_classes, hidden_size=64, learning_rate=2e-4):\n",
"\n",
" super().__init__()\n",
"\n",
" # We take in input dimensions as parameters and use those to dynamically build model.\n",
" self.channels = channels\n",
" self.width = width\n",
" self.height = height\n",
" self.num_classes = num_classes\n",
" self.hidden_size = hidden_size\n",
" self.learning_rate = learning_rate\n",
"\n",
" self.model = nn.Sequential(\n",
" nn.Flatten(),\n",
" nn.Linear(channels * width * height, hidden_size),\n",
" nn.ReLU(),\n",
" nn.Dropout(0.1),\n",
" nn.Linear(hidden_size, hidden_size),\n",
" nn.ReLU(),\n",
" nn.Dropout(0.1),\n",
" nn.Linear(hidden_size, num_classes)\n",
" )\n",
"\n",
" def forward(self, x):\n",
" x = self.model(x)\n",
" return F.log_softmax(x, dim=1)\n",
"\n",
" def training_step(self, batch, batch_idx):\n",
" x, y = batch\n",
" logits = self(x)\n",
" loss = F.nll_loss(logits, y)\n",
" return loss\n",
"\n",
" def validation_step(self, batch, batch_idx):\n",
"\n",
" x, y = batch\n",
" logits = self(x)\n",
" loss = F.nll_loss(logits, y)\n",
" preds = torch.argmax(logits, dim=1)\n",
" acc = accuracy(preds, y)\n",
" self.log('val_loss', loss, prog_bar=True)\n",
" self.log('val_acc', acc, prog_bar=True)\n",
" return loss\n",
"\n",
" def configure_optimizers(self):\n",
" optimizer = torch.optim.Adam(self.parameters(), lr=self.learning_rate)\n",
" return optimizer"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "G4Z5olPe-xEo"
},
"source": [
"## Training the `LitModel` using the `MNISTDataModule`\n",
"\n",
"Now, we initialize and train the `LitModel` using the `MNISTDataModule`'s configuration settings and dataloaders."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "kV48vP_9mEli"
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"outputs": [],
"source": [
"# Init DataModule\n",
"dm = MNISTDataModule()\n",
"# Init model from datamodule's attributes\n",
"model = LitModel(*dm.size(), dm.num_classes)\n",
"# Init trainer\n",
"trainer = pl.Trainer(max_epochs=3, progress_bar_refresh_rate=20, gpus=1)\n",
"# Pass the datamodule as arg to trainer.fit to override model hooks :)\n",
"trainer.fit(model, dm)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "WNxrugIGRRv5"
},
"source": [
"## Defining the CIFAR10 DataModule\n",
"\n",
"Lets prove the `LitModel` we made earlier is dataset agnostic by defining a new datamodule for the CIFAR10 dataset."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "1tkaYLU7RT5P"
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"outputs": [],
"source": [
"class CIFAR10DataModule(pl.LightningDataModule):\n",
"\n",
" def __init__(self, data_dir: str = './'):\n",
" super().__init__()\n",
" self.data_dir = data_dir\n",
" self.transform = transforms.Compose([\n",
" transforms.ToTensor(),\n",
" transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))\n",
" ])\n",
"\n",
" self.dims = (3, 32, 32)\n",
" self.num_classes = 10\n",
"\n",
" def prepare_data(self):\n",
" # download\n",
" CIFAR10(self.data_dir, train=True, download=True)\n",
" CIFAR10(self.data_dir, train=False, download=True)\n",
"\n",
" def setup(self, stage=None):\n",
"\n",
" # Assign train/val datasets for use in dataloaders\n",
" if stage == 'fit' or stage is None:\n",
" cifar_full = CIFAR10(self.data_dir, train=True, transform=self.transform)\n",
" self.cifar_train, self.cifar_val = random_split(cifar_full, [45000, 5000])\n",
"\n",
" # Assign test dataset for use in dataloader(s)\n",
" if stage == 'test' or stage is None:\n",
" self.cifar_test = CIFAR10(self.data_dir, train=False, transform=self.transform)\n",
"\n",
" def train_dataloader(self):\n",
" return DataLoader(self.cifar_train, batch_size=32)\n",
"\n",
" def val_dataloader(self):\n",
" return DataLoader(self.cifar_val, batch_size=32)\n",
"\n",
" def test_dataloader(self):\n",
" return DataLoader(self.cifar_test, batch_size=32)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text",
"id": "BrXxf3oX_gsZ"
},
"source": [
"## Training the `LitModel` using the `CIFAR10DataModule`\n",
"\n",
"Our model isn't very good, so it will perform pretty badly on the CIFAR10 dataset.\n",
"\n",
"The point here is that we can see that our `LitModel` has no problem using a different datamodule as its input data."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"colab": {},
"colab_type": "code",
"id": "sd-SbWi_krdj"
},
"outputs": [],
"source": [
"dm = CIFAR10DataModule()\n",
"model = LitModel(*dm.size(), dm.num_classes, hidden_size=256)\n",
"trainer = pl.Trainer(max_epochs=5, progress_bar_refresh_rate=20, gpus=1)\n",
"trainer.fit(model, dm)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<code style=\"color:#792ee5;\">\n",
" <h1> <strong> Congratulations - Time to Join the Community! </strong> </h1>\n",
"</code>\n",
"\n",
"Congratulations on completing this notebook tutorial! If you enjoyed this and would like to join the Lightning movement, you can do so in the following ways!\n",
"\n",
"### Star [Lightning](https://github.com/PyTorchLightning/pytorch-lightning) on GitHub\n",
"The easiest way to help our community is just by starring the GitHub repos! This helps raise awareness of the cool tools we're building.\n",
"\n",
"* Please, star [Lightning](https://github.com/PyTorchLightning/pytorch-lightning)\n",
"\n",
"### Join our [Slack](https://join.slack.com/t/pytorch-lightning/shared_invite/zt-f6bl2l0l-JYMK3tbAgAmGRrlNr00f1A)!\n",
"The best way to keep up to date on the latest advancements is to join our community! Make sure to introduce yourself and share your interests in `#general` channel\n",
"\n",
"### Interested by SOTA AI models ! Check out [Bolt](https://github.com/PyTorchLightning/pytorch-lightning-bolts)\n",
"Bolts has a collection of state-of-the-art models, all implemented in [Lightning](https://github.com/PyTorchLightning/pytorch-lightning) and can be easily integrated within your own projects.\n",
"\n",
"* Please, star [Bolt](https://github.com/PyTorchLightning/pytorch-lightning-bolts)\n",
"\n",
"### Contributions !\n",
"The best way to contribute to our community is to become a code contributor! At any time you can go to [Lightning](https://github.com/PyTorchLightning/pytorch-lightning) or [Bolt](https://github.com/PyTorchLightning/pytorch-lightning-bolts) GitHub Issues page and filter for \"good first issue\". \n",
"\n",
"* [Lightning good first issue](https://github.com/PyTorchLightning/pytorch-lightning/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22)\n",
"* [Bolt good first issue](https://github.com/PyTorchLightning/pytorch-lightning-bolts/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22)\n",
"* You can also contribute your own notebooks with useful examples !\n",
"\n",
"### Great thanks from the entire Pytorch Lightning Team for your interest !\n",
"\n",
"<img src=\"https://github.com/PyTorchLightning/pytorch-lightning/blob/master/docs/source/_static/images/logo.png?raw=true\" width=\"800\" height=\"200\" />"
]
}
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