Collect Metrics#

One of the key features of 3LC is the ability to collect fine-grained metrics from input Tables. This guide outlines how to collect and accumulate per-sample metrics to analyze your datasets efficiently.


tlc uses the concept of a metrics collector, which is a mechanism that defines how models and samples are combined to produce metrics. In practice, it is as simple as a function that takes a batch of samples and a batch of predictions and returns a dictionary of metrics. Schema information is provided to the metrics collector to allow customization of the metrics.

The Python package includes a set of basic collectors, but you can also create custom collectors to fit specific needs.

When collecting per-sample metrics using an ML model, it is often desirable to run just a single inference pass through each dataset for metric collection. This is achieved by calling the collect_metrics() function, where you specify the model, the Table, and the metrics collectors you wish to use.

If collecting metrics in a single pass isn’t a necessity for your workflow, or if you wish to add metrics to a Run using a more direct approach, the Run.add_metrics_data() function provides a straightforward alternative.

Metrics Collectors#

The metrics_collectors module provides a variety of pre-defined metrics collectors, including:

To create your own metrics collectors, you have two options:


The Example Notebooks section offers multiple demonstrations of supported workflows:

  • MNIST Notebook: Demonstrates a custom metrics collector for classification metrics.

  • CIFAR10 Notebook: Uses a standard metrics collector for multi-class classification. Also shows usage of the EmbeddingsMetricsCollector for capturing hidden layer activations and dimensionality reduction via UMAP.

  • HuggingFace IMDB Notebook: Introduces a custom metrics collection method that works with the HuggingFace Trainer class.

  • HuggingFace CIFAR 100 Notebook: Utilizes a HuggingFace dataset and computes 2D embeddings.

  • Detectron2 Balloons: Trains an object detection model and gathers bounding box metrics with detectron2.

  • Detectron2 COCO128: Executes inference and gathers bounding box metrics using detectron2.

  • Per Bounding Box Metrics: Describes metric collection for individual bounding boxes in images.

  • Per Bounding Box Embeddings: Covers embedding collection for bounding boxes and uses UMAP for dimensionality reduction.

  • Bounding Box Classifier: Details an advanced workflow where a model is trained to classify bounding boxes in an image, which can be used to in conjunction with an object detection model to find bounding boxes of special interest.

  • PyTorch Lightning SegFormer: Demonstrates how to use a custom metrics collector for collecting predicted masks from a semantic segmentation model.