From dc88b4c60795de275c0f5f7019f2c155deced594 Mon Sep 17 00:00:00 2001
From: spinkney <sean.pinkney@gmail.com>
Date: Sun, 4 Jan 2026 15:59:23 -0500
Subject: [PATCH] minor change to use constant

---
 stan/math/prim/fun/log1m_exp.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stan/math/prim/fun/log1m_exp.hpp b/stan/math/prim/fun/log1m_exp.hpp
index b4d6df49f28..a7d2f6c3a36 100644
--- a/stan/math/prim/fun/log1m_exp.hpp
+++ b/stan/math/prim/fun/log1m_exp.hpp
@@ -49,7 +49,7 @@ inline double log1m_exp(double a) {
   using std::log;
   if (a > 0) {
     return NOT_A_NUMBER;
-  } else if (a > -0.693147) {
+  } else if (a > LOG_HALF) {
     return log(-expm1(a));  // 0.693147 ~= log(2)
   } else {
     return log1m(exp(a));