[BUG] `Hurdle` CDF is wrong for negative values

[tingiskhan]

Describe the bug

The CDF of the Hurdle distribution should return 0 for values < 0, currently returns 1-p.

Kudos to @Khushmagrawal for finding it!

To Reproduce

E.g.

from skpro.distributions import Hurdle, Normal

dist = Normal(mu=0.0, sigma=1.0)
hurdle = Hurdle(0.5, dist)

samples = -1.0

p = hurdle.cdf(samples)

Expected behavior

Should be zero for all values less than 0.

Environment

Not nocessary for skpro <= 2.10

Additional context

[Khushmagrawal]

Hey @tingiskhan, should I work on this?

[tingiskhan]

Hey @tingiskhan, should I work on this?

I have a PR inbound, I’ll let you know when it’s live, should be within the hour!

[tingiskhan]

@fkiraly, this is perhaps part of a bigger “problem” regarding the support for all distributions? Perhaps it would make sense for all distributions to have an attribute indicating its support? Numoyro/pyro does this.

[fkiraly]

@fkiraly, this is perhaps part of a bigger “problem” regarding the support for all distributions? Perhaps it would make sense for all distributions to have an attribute indicating its support? Numoyro/pyro does this.

I absolutely agree! Though so far no one wanted to work on this. :-(
#244

Maybe you can be the one :-) 🥇

[fkiraly]

I remember @VascoSch92 may have wanted to take this on, but that was a longer time ago. I have not heard of him since we met at a German castle in the mountains. True story.

[tingiskhan]

I absolutely agree! Though so far no one wanted to work on this. :-( #244

Maybe you can be the one :-) 🥇

Sounds fun, I'll take a crack at it. I'll open a draft PR for discussing a possible solution

[VascoSch92]

I remember @VascoSch92 may have wanted to take this on, but that was a longer time ago. I have not heard of him since we met at a German castle in the mountains. True story.

Haha, true story! Are we going to repeat the experience this year?

[fkiraly]

Haha, true story! Are we going to repeat the experience this year?

(you mean, next?)
Not sure, no invitations yet.

But we will probably have some form of in-person developer days in 2026!

[VascoSch92]

Yes exactly next year...