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508 lines
22 KiB
Markdown
508 lines
22 KiB
Markdown
---
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title: Training Models
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next: /usage/projects
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menu:
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- ['Introduction', 'basics']
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- ['CLI & Config', 'cli-config']
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- ['Transfer Learning', 'transfer-learning']
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- ['Custom Models', 'custom-models']
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- ['Parallel Training', 'parallel-training']
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- ['Internal API', 'api']
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---
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## Introduction to training models {#basics hidden="true"}
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import Training101 from 'usage/101/\_training.md'
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<Training101 />
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<Infobox title="Tip: Try the Prodigy annotation tool">
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[](https://prodi.gy)
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If you need to label a lot of data, check out [Prodigy](https://prodi.gy), a
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new, active learning-powered annotation tool we've developed. Prodigy is fast
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and extensible, and comes with a modern **web application** that helps you
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collect training data faster. It integrates seamlessly with spaCy, pre-selects
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the **most relevant examples** for annotation, and lets you train and evaluate
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ready-to-use spaCy models.
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</Infobox>
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## Training CLI & config {#cli-config}
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<!-- TODO: intro describing the new v3 training philosophy -->
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The recommended way to train your spaCy models is via the
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[`spacy train`](/api/cli#train) command on the command line.
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1. The **training and evaluation data** in spaCy's
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[binary `.spacy` format](/api/data-formats#binary-training) created using
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[`spacy convert`](/api/cli#convert).
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2. A [`config.cfg`](#config) **configuration file** with all settings and
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hyperparameters.
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3. An optional **Python file** to register
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[custom models and architectures](#custom-models).
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<!-- TODO: decide how we want to present the "getting started" workflow here, get a default config etc. -->
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```bash
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$ python -m spacy train train.spacy dev.spacy config.cfg --output ./output
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```
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> #### Tip: Debug your data
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>
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> The [`debug-data` command](/api/cli#debug-data) lets you analyze and validate
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> your training and development data, get useful stats, and find problems like
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> invalid entity annotations, cyclic dependencies, low data labels and more.
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>
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> ```bash
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> $ python -m spacy debug-data en train.spacy dev.spacy --verbose
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> ```
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<Project id="some_example_project">
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The easiest way to get started with an end-to-end training process is to clone a
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[project](/usage/projects) template. Projects let you manage multi-step
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workflows, from data preprocessing to training and packaging your model.
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</Project>
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<Accordion title="Understanding the training output">
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When you train a model using the [`spacy train`](/api/cli#train) command, you'll
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see a table showing metrics after each pass over the data. Here's what those
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metrics means:
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<!-- TODO: update table below and include note about scores in config -->
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| Name | Description |
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| ---------- | ------------------------------------------------------------------------------------------------- |
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| `Dep Loss` | Training loss for dependency parser. Should decrease, but usually not to 0. |
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| `NER Loss` | Training loss for named entity recognizer. Should decrease, but usually not to 0. |
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| `UAS` | Unlabeled attachment score for parser. The percentage of unlabeled correct arcs. Should increase. |
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| `NER P.` | NER precision on development data. Should increase. |
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| `NER R.` | NER recall on development data. Should increase. |
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| `NER F.` | NER F-score on development data. Should increase. |
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| `Tag %` | Fine-grained part-of-speech tag accuracy on development data. Should increase. |
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| `Token %` | Tokenization accuracy on development data. |
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| `CPU WPS` | Prediction speed on CPU in words per second, if available. Should stay stable. |
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| `GPU WPS` | Prediction speed on GPU in words per second, if available. Should stay stable. |
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Note that if the development data has raw text, some of the gold-standard
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entities might not align to the predicted tokenization. These tokenization
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errors are **excluded from the NER evaluation**. If your tokenization makes it
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impossible for the model to predict 50% of your entities, your NER F-score might
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still look good.
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</Accordion>
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---
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### Training config files {#config}
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> #### Migration from spaCy v2.x
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>
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> TODO: once we have an answer for how to update the training command
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> (`spacy migrate`?), add details here
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Training config files include all **settings and hyperparameters** for training
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your model. Instead of providing lots of arguments on the command line, you only
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need to pass your `config.cfg` file to [`spacy train`](/api/cli#train). Under
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the hood, the training config uses the
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[configuration system](https://thinc.ai/docs/usage-config) provided by our
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machine learning library [Thinc](https://thinc.ai). This also makes it easy to
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integrate custom models and architectures, written in your framework of choice.
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Some of the main advantages and features of spaCy's training config are:
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- **Structured sections.** The config is grouped into sections, and nested
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sections are defined using the `.` notation. For example, `[components.ner]`
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defines the settings for the pipeline's named entity recognizer. The config
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can be loaded as a Python dict.
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- **References to registered functions.** Sections can refer to registered
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functions like [model architectures](/api/architectures),
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[optimizers](https://thinc.ai/docs/api-optimizers) or
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[schedules](https://thinc.ai/docs/api-schedules) and define arguments that are
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passed into them. You can also register your own functions to define
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[custom architectures](#custom-models), reference them in your config and
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tweak their parameters.
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- **Interpolation.** If you have hyperparameters used by multiple components,
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define them once and reference them as variables.
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- **Reproducibility with no hidden defaults.** The config file is the "single
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source of truth" and includes all settings. <!-- TODO: explain this better -->
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- **Automated checks and validation.** When you load a config, spaCy checks if
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the settings are complete and if all values have the correct types. This lets
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you catch potential mistakes early. In your custom architectures, you can use
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Python [type hints](https://docs.python.org/3/library/typing.html) to tell the
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config which types of data to expect.
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```ini
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https://github.com/explosion/spaCy/blob/develop/spacy/default_config.cfg
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```
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Under the hood, the config is parsed into a dictionary. It's divided into
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sections and subsections, indicated by the square brackets and dot notation. For
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example, `[training]` is a section and `[training.batch_size]` a subsections.
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Subsections can define values, just like a dictionary, or use the `@` syntax to
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refer to [registered functions](#config-functions). This allows the config to
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not just define static settings, but also construct objects like architectures,
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schedules, optimizers or any other custom components. The main top-level
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sections of a config file are:
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| Section | Description |
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| ------------- | --------------------------------------------------------------------------------------------------------------------- |
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| `training` | Settings and controls for the training and evaluation process. |
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| `pretraining` | Optional settings and controls for the [language model pretraining](#pretraining). |
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| `nlp` | Definition of the `nlp` object, its tokenizer and [processing pipeline](/usage/processing-pipelines) component names. |
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| `components` | Definitions of the [pipeline components](/usage/processing-pipelines) and their models. |
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<Infobox title="Config format and settings" emoji="📖">
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For a full overview of spaCy's config format and settings, see the
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[training format documentation](/api/data-formats#config) and
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[Thinc's config system docs](https://thinc.ai/usage/config). The settings
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available for the different architectures are documented with the
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[model architectures API](/api/architectures). See the Thinc documentation for
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[optimizers](https://thinc.ai/docs/api-optimizers) and
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[schedules](https://thinc.ai/docs/api-schedules).
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</Infobox>
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#### Overwriting config settings on the command line {#config-overrides}
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The config system means that you can define all settings **in one place** and in
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a consistent format. There are no command-line arguments that need to be set,
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and no hidden defaults. However, there can still be scenarios where you may want
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to override config settings when you run [`spacy train`](/api/cli#train). This
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includes **file paths** to vectors or other resources that shouldn't be
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hard-code in a config file, or **system-dependent settings**.
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For cases like this, you can set additional command-line options starting with
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`--` that correspond to the config section and value to override. For example,
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`--training.batch_size 128` sets the `batch_size` value in the `[training]`
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block to `128`.
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```bash
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$ python -m spacy train train.spacy dev.spacy config.cfg
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--training.batch_size 128 --nlp.vectors /path/to/vectors
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```
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Only existing sections and values in the config can be overwritten. At the end
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of the training, the final filled `config.cfg` is exported with your model, so
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you'll always have a record of the settings that were used, including your
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overrides.
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#### Using registered functions {#config-functions}
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The training configuration defined in the config file doesn't have to only
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consist of static values. Some settings can also be **functions**. For instance,
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the `batch_size` can be a number that doesn't change, or a schedule, like a
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sequence of compounding values, which has shown to be an effective trick (see
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[Smith et al., 2017](https://arxiv.org/abs/1711.00489)).
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```ini
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### With static value
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[training]
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batch_size = 128
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```
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To refer to a function instead, you can make `[training.batch_size]` its own
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section and use the `@` syntax specify the function and its arguments – in this
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case [`compounding.v1`](https://thinc.ai/docs/api-schedules#compounding) defined
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in the [function registry](/api/top-level#registry). All other values defined in
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the block are passed to the function as keyword arguments when it's initialized.
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You can also use this mechanism to register
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[custom implementations and architectures](#custom-models) and reference them
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from your configs.
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> #### How the config is resolved
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>
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> The config file is parsed into a regular dictionary and is resolved and
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> validated **bottom-up**. Arguments provided for registered functions are
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> checked against the function's signature and type annotations. The return
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> value of a registered function can also be passed into another function – for
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> instance, a learning rate schedule can be provided as the an argument of an
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> optimizer.
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```ini
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### With registered function
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[training.batch_size]
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@schedules = "compounding.v1"
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start = 100
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stop = 1000
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compound = 1.001
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```
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### Model architectures {#model-architectures}
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<!-- TODO: refer to architectures API: /api/architectures. This should document the architectures in spacy/ml/models -->
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<!-- TODO: how do we document the default configs? -->
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## Transfer learning {#transfer-learning}
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### Using transformer models like BERT {#transformers}
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<!-- TODO: document usage of spacy-transformers, refer to example config/project -->
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<Project id="en_core_bert">
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Try out a BERT-based model pipeline using this project template: swap in your
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data, edit the settings and hyperparameters and train, evaluate, package and
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visualize your model.
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</Project>
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### Pretraining with spaCy {#pretraining}
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<!-- TODO: document spacy pretrain -->
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## Custom model implementations and architectures {#custom-models}
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<!-- TODO: intro, should summarise what spaCy v3 can do and that you can now use fully custom implementations, models defined in PyTorch and TF, etc. etc. -->
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### Training with custom code {#custom-code}
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The [`spacy train`](/api/cli#train) recipe lets you specify an optional argument
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`--code` that points to a Python file. The file is imported before training and
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allows you to add custom functions and architectures to the function registry
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that can then be referenced from your `config.cfg`. This lets you train spaCy
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models with custom components, without having to re-implement the whole training
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workflow.
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For example, let's say you've implemented your own batch size schedule to use
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during training. The `@spacy.registry.schedules` decorator lets you register
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that function in the `schedules` [registry](/api/top-level#registry) and assign
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it a string name:
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> #### Why the version in the name?
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>
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> A big benefit of the config system is that it makes your experiments
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> reproducible. We recommend versioning the functions you register, especially
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> if you expect them to change (like a new model architecture). This way, you
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> know that a config referencing `v1` means a different function than a config
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> referencing `v2`.
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```python
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### functions.py
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import spacy
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@spacy.registry.schedules("my_custom_schedule.v1")
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def my_custom_schedule(start: int = 1, factor: int = 1.001):
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while True:
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yield start
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start = start * factor
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```
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In your config, you can now reference the schedule in the
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`[training.batch_size]` block via `@schedules`. If a block contains a key
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starting with an `@`, it's interpreted as a reference to a function. All other
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settings in the block will be passed to the function as keyword arguments. Keep
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in mind that the config shouldn't have any hidden defaults and all arguments on
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the functions need to be represented in the config.
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<!-- TODO: this needs to be updated once we've decided on a workflow for "fill config" -->
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```ini
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### config.cfg (excerpt)
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[training.batch_size]
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@schedules = "my_custom_schedule.v1"
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start = 2
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factor = 1.005
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```
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You can now run [`spacy train`](/api/cli#train) with the `config.cfg` and your
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custom `functions.py` as the argument `--code`. Before loading the config, spaCy
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will import the `functions.py` module and your custom functions will be
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registered.
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```bash
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### Training with custom code {wrap="true"}
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python -m spacy train train.spacy dev.spacy config.cfg --output ./output --code ./functions.py
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```
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<Infobox title="Tip: Use Python type hints" emoji="💡">
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spaCy's configs are powered by our machine learning library Thinc's
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[configuration system](https://thinc.ai/docs/usage-config), which supports
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[type hints](https://docs.python.org/3/library/typing.html) and even
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[advanced type annotations](https://thinc.ai/docs/usage-config#advanced-types)
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using [`pydantic`](https://github.com/samuelcolvin/pydantic). If your registered
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function provides type hints, the values that are passed in will be checked
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against the expected types. For example, `start: int` in the example above will
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ensure that the value received as the argument `start` is an integer. If the
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value can't be cast to an integer, spaCy will raise an error.
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`start: pydantic.StrictInt` will force the value to be an integer and raise an
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error if it's not – for instance, if your config defines a float.
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</Infobox>
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### Wrapping PyTorch and TensorFlow {#custom-frameworks}
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<!-- TODO: -->
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<Project id="example_pytorch_model">
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Lorem ipsum dolor sit amet, consectetur adipiscing elit. Phasellus interdum
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sodales lectus, ut sodales orci ullamcorper id. Sed condimentum neque ut erat
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mattis pretium.
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</Project>
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### Defining custom architectures {#custom-architectures}
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<!-- TODO: this could maybe be a more general example of using Thinc to compose some layers? We don't want to go too deep here and probably want to focus on a simple architecture example to show how it works -->
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## Parallel Training with Ray {#parallel-training}
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<!-- TODO: document Ray integration -->
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<Project id="some_example_project">
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Lorem ipsum dolor sit amet, consectetur adipiscing elit. Phasellus interdum
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sodales lectus, ut sodales orci ullamcorper id. Sed condimentum neque ut erat
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mattis pretium.
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</Project>
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## Internal training API {#api}
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<Infobox variant="warning">
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spaCy gives you full control over the training loop. However, for most use
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cases, it's recommended to train your models via the
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[`spacy train`](/api/cli#train) command with a [`config.cfg`](#config) to keep
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track of your settings and hyperparameters, instead of writing your own training
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scripts from scratch.
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[Custom registered functions](/usage/training/#custom-code) should typically
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give you everything you need to train fully custom models with
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[`spacy train`](/api/cli#train).
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</Infobox>
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<!-- TODO: maybe add something about why the Example class is great and its benefits, and how it's passed around, holds the alignment etc -->
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The [`Example`](/api/example) object contains annotated training data, also
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called the **gold standard**. It's initialized with a [`Doc`](/api/doc) object
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that will hold the predictions, and another `Doc` object that holds the
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gold-standard annotations. Here's an example of a simple `Example` for
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part-of-speech tags:
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```python
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words = ["I", "like", "stuff"]
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predicted = Doc(vocab, words=words)
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# create the reference Doc with gold-standard TAG annotations
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tags = ["NOUN", "VERB", "NOUN"]
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tag_ids = [vocab.strings.add(tag) for tag in tags]
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reference = Doc(vocab, words=words).from_array("TAG", numpy.array(tag_ids, dtype="uint64"))
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example = Example(predicted, reference)
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```
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Alternatively, the `reference` `Doc` with the gold-standard annotations can be
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created from a dictionary with keyword arguments specifying the annotations,
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like `tags` or `entities`. Using the `Example` object and its gold-standard
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annotations, the model can be updated to learn a sentence of three words with
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their assigned part-of-speech tags.
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> #### About the tag map
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>
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> The tag map is part of the vocabulary and defines the annotation scheme. If
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> you're training a new language model, this will let you map the tags present
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> in the treebank you train on to spaCy's tag scheme:
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>
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> ```python
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> tag_map = {"N": {"pos": "NOUN"}, "V": {"pos": "VERB"}}
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> vocab = Vocab(tag_map=tag_map)
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> ```
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```python
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words = ["I", "like", "stuff"]
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tags = ["NOUN", "VERB", "NOUN"]
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predicted = Doc(nlp.vocab, words=words)
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example = Example.from_dict(predicted, {"tags": tags})
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```
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Here's another example that shows how to define gold-standard named entities.
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The letters added before the labels refer to the tags of the
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[BILUO scheme](/usage/linguistic-features#updating-biluo) – `O` is a token
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outside an entity, `U` an single entity unit, `B` the beginning of an entity,
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`I` a token inside an entity and `L` the last token of an entity.
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```python
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doc = Doc(nlp.vocab, words=["Facebook", "released", "React", "in", "2014"])
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example = Example.from_dict(doc, {"entities": ["U-ORG", "O", "U-TECHNOLOGY", "O", "U-DATE"]})
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```
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<Infobox title="Migrating from v2.x" variant="warning">
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As of v3.0, the [`Example`](/api/example) object replaces the `GoldParse` class.
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It can be constructed in a very similar way, from a `Doc` and a dictionary of
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annotations:
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```diff
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- gold = GoldParse(doc, entities=entities)
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+ example = Example.from_dict(doc, {"entities": entities})
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```
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</Infobox>
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Of course, it's not enough to only show a model a single example once.
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Especially if you only have few examples, you'll want to train for a **number of
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iterations**. At each iteration, the training data is **shuffled** to ensure the
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model doesn't make any generalizations based on the order of examples. Another
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technique to improve the learning results is to set a **dropout rate**, a rate
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at which to randomly "drop" individual features and representations. This makes
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it harder for the model to memorize the training data. For example, a `0.25`
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dropout means that each feature or internal representation has a 1/4 likelihood
|
||
of being dropped.
|
||
|
||
> - [`nlp`](/api/language): The `nlp` object with the model.
|
||
> - [`nlp.begin_training`](/api/language#begin_training): Start the training and
|
||
> return an optimizer to update the model's weights.
|
||
> - [`Optimizer`](https://thinc.ai/docs/api-optimizers): Function that holds
|
||
> state between updates.
|
||
> - [`nlp.update`](/api/language#update): Update model with examples.
|
||
> - [`Example`](/api/example): object holding predictions and gold-standard
|
||
> annotations.
|
||
> - [`nlp.to_disk`](/api/language#to_disk): Save the updated model to a
|
||
> directory.
|
||
|
||
```python
|
||
### Example training loop
|
||
optimizer = nlp.begin_training()
|
||
for itn in range(100):
|
||
random.shuffle(train_data)
|
||
for raw_text, entity_offsets in train_data:
|
||
doc = nlp.make_doc(raw_text)
|
||
example = Example.from_dict(doc, {"entities": entity_offsets})
|
||
nlp.update([example], sgd=optimizer)
|
||
nlp.to_disk("/model")
|
||
```
|
||
|
||
The [`nlp.update`](/api/language#update) method takes the following arguments:
|
||
|
||
| Name | Description |
|
||
| ---------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|
||
| `examples` | [`Example`](/api/example) objects. The `update` method takes a sequence of them, so you can batch up your training examples. |
|
||
| `drop` | Dropout rate. Makes it harder for the model to just memorize the data. |
|
||
| `sgd` | An [`Optimizer`](https://thinc.ai/docs/api-optimizers) object, which updated the model's weights. If not set, spaCy will create a new one and save it for further use. |
|
||
|
||
<Infobox title="Migrating from v2.x" variant="warning">
|
||
|
||
As of v3.0, the [`Example`](/api/example) object replaces the `GoldParse` class
|
||
and the "simple training style" of calling `nlp.update` with a text and a
|
||
dictionary of annotations. Updating your code to use the `Example` object should
|
||
be very straightforward: you can call
|
||
[`Example.from_dict`](/api/example#from_dict) with a [`Doc`](/api/doc) and the
|
||
dictionary of annotations:
|
||
|
||
```diff
|
||
text = "Facebook released React in 2014"
|
||
annotations = {"entities": ["U-ORG", "O", "U-TECHNOLOGY", "O", "U-DATE"]}
|
||
+ example = Example.from_dict(nlp.make_doc(text), {"entities": entities})
|
||
- nlp.update([text], [annotations])
|
||
+ nlp.update([example])
|
||
```
|
||
|
||
</Infobox>
|