Dear Zfit developers,
When describing a chain decay in phasespace I may want to leave unspecified the mass of an intermediate state. I read on the Particle() instance docstring that the mass is an optional argument, but when I don't do it I get error.
phasespaceimplements the phasespace integral, the mass of all states needs to be specified
So (I have to go, maybe back a little later), what you need to do is to say where the pdf should sample from. Have a look at this unittest, where a custom sampler is created: https://github.com/zfit/zfit/blob/develop/tests/test_sampling.py#L138
and have a look at the docs of accept_reject_sample
The sample you return has to have the same dims as the pdf was meant to be used. E.g. since you generate 4 particles with 4 properties, your pdf should be defined in 16 obs