Skip to main content

Prerequisites

Have a dataset uploaded to Laminar, or collected from traces. See datasets for more information.

Defining data

To run an evaluation with a Laminar dataset, you pass the dataset object as data instead of a list of dictionaries. Use LaminarDataset to create a dataset object. The dataset name should match the name of the dataset in Laminar. The constructor also takes an optional fetch_size/fetchSize parameter, which specifies the number of datapoints to fetch at once. The default value is 25. We strongly recommend setting this value to a number that is a multiple of the evaluation batch size for best performance.

Technical details and extension

LaminarDataset is an implementation of an abstract class EvaluationDataset which defines 2 methods besides initialization:
  • __len__ (size in JS): Returns the number of datapoints in the dataset.
  • __getitem__ (get in JS): Returns a single datapoint by index.
We also implement a concrete slice method to make slicing easier than using __getitem__ directly. This is inspired by the PyTorch Dataset class, and is designed to be used in a similar way. You can re-use the EvaluationDataset class to create your own dataset classes, for example, to fetch data from a database or an API.