# Possible Issue with gamma\_lccdf

**URL:** <https://discourse.mc-stan.org/t/possible-issue-with-gamma-lccdf/40390>\
**Category:** Developers\
**Created:** [September 22, 2025, 4:33pm UTC](https://discourse.mc-stan.org/t/possible-issue-with-gamma-lccdf/40390 "2025-09-22T16:33:15Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![s.maskell](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/s.maskell/32/6626_2.png) [@s.maskell](https://discourse.mc-stan.org/u/s.maskell)\
**Post date:** [September 29, 2025, 7:45pm UTC](https://discourse.mc-stan.org/t/possible-issue-with-gamma-lccdf/40390/3 "2025-09-29T19:45:58Z")

</div>

Thanks. I think implementing our own log ccdf using Stan’s primitives is a good idea. It seems the same idea was useful for the cdf (here: [Minimal censored Gamma with VERY bad performance](https://discourse.mc-stan.org/t/minimal-censored-gamma-with-very-bad-performance/27922)). My guess is that we need a mycdf(.) that calls gamma\_q(.).

---

_[View the full topic](https://discourse.mc-stan.org/t/possible-issue-with-gamma-lccdf/40390)._