Update stan/math/prim/prob/yule_simon_lccdf.hpp

lingium · SteveBronder · web-flow · commit 94dda8f75592 · 2025-10-04T17:50:52.000+08:00
Co-authored-by: Steve Bronder &lt;Stevo15025@gmail.com&gt;
diff --git a/stan/math/prim/prob/yule_simon_lccdf.hpp b/stan/math/prim/prob/yule_simon_lccdf.hpp
@@ -71,7 +71,7 @@ inline return_type_t<T_alpha> yule_simon_lccdf(const T_n& n,
     auto nap1 = n_vec.val(i) + ap1;
     log_ccdf += lgamma(ap1) + lgamma(np1) - lgamma(nap1);
 
-    if constexpr (!is_constant<T_alpha>::value) {
+    if constexpr (is_autodiff_v<T_alpha>) {
       partials<0>(ops_partials)[i] += digamma(ap1) - digamma(nap1);
     }
   }

Original file line number	Diff line number	Diff line change
`@@ -71,7 +71,7 @@ inline return_type_t<T_alpha> yule_simon_lccdf(const T_n& n,`
`71`	`71`	`auto nap1 = n_vec.val(i) + ap1;`
`72`	`72`	`log_ccdf += lgamma(ap1) + lgamma(np1) - lgamma(nap1);`
`73`	`73`
`74`		`- if constexpr (!is_constant<T_alpha>::value) {`
	`74`	`+ if constexpr (is_autodiff_v<T_alpha>) {`
`75`	`75`	`partials<0>(ops_partials)[i] += digamma(ap1) - digamma(nap1);`
`76`	`76`	`}`
`77`	`77`	`}`