Power-constrained limits

[mpoehlmann]

The examples and documentation for producing upper limits with the CLs method are excellent. For comparison, I'm trying to compute upper limits with the power-constrained limit method (https://arxiv.org/abs/1105.3166). Is this possible with the pyhf package?

[kratsg]

Interesting (this is new to me). I had a quick read and I will ask @cranmer (one of the authors) to chime in as well and correct me as I have probably misunderstood but... my gut feeling is that you will need to create you own calculator, but you can use pyhf to provide the pdf you need, and calculate the PCL yourself with a manual calculator/limit finding routine. Specifically, if you follow through the pyhf.infer.mle.hypotest function (

pyhf/src/pyhf/infer/__init__.py

Line 20 in 8e242c9

def hypotest(

) and make something similar to an AsymptoticCalculator, you should be able to use pyhf partially for this.

We don't provide PCL out of the box, but if you manage to provide a usable calculator that fits into the code, we could possibly be willing to support this as well but I would need to discuss with the other core developers before we can make a statement about the inclusion of such a feature in the future (but I know we would be willing to discuss it of course!).