[flaviojuvenal]

Not a full featured framework, but pytorch-metric-learning has data loaders, lossess, etc. to facilitate similarity learning: https://github.com/KevinMusgrave/pytorch-metric-learning

Disclaimer: I've made some contributions to it.

[dimitry12]

Seconding this. PML is high quality, active, and well documented.

[generall]

PML is a great collection of implementations, but not the best framework. Also you can use PML with Quaterion: https://github.com/qdrant/quaterion/blob/master/examples/tra...