pyhf: a pure Python statistical fitting library for High Energy Physics with tensors and autograd

In experimental high energy physics, the common HistFactory p.d.f. template and fitting tools have only existed within the C++ based ROOT framework developed and maintained by CERN. pyhf is a pure-Python implementation of that statistical model for multi-bin histogram-based analysis with interval estimation based on 'Asymptotic formulae for likelihood-based tests of new physics' [arxiv:1007.1727]. pyhf supports modern computational graph libraries such as TensorFlow and PyTorch as computational backends in order to make use of features such as auto-differentiation and GPU acceleration and defines models with an expressive JSON schema.