From 0abf5d54e0f5e7d8ab13eff42aa4483534cd6306 Mon Sep 17 00:00:00 2001
From: Brian Ward <bward@flatironinstitute.org>
Date: Thu, 12 Dec 2024 15:07:55 -0500
Subject: [PATCH] Changes per review

---
 src/stan/services/optimize/laplace_sample.hpp | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/stan/services/optimize/laplace_sample.hpp b/src/stan/services/optimize/laplace_sample.hpp
index 423c8c8ea4..85d3127403 100644
--- a/src/stan/services/optimize/laplace_sample.hpp
+++ b/src/stan/services/optimize/laplace_sample.hpp
@@ -54,12 +54,10 @@ void laplace_sample(const Model& model, const Eigen::VectorXd& theta_hat,
 
   // create log density functor for vars and vals
   std::stringstream log_density_msgs;
-  auto log_density_fun
-      = [&](const Eigen::Matrix<stan::math::var, -1, 1>& theta) {
-          return model.template log_prob<true, jacobian, stan::math::var>(
-              const_cast<Eigen::Matrix<stan::math::var, -1, 1>&>(theta),
-              &log_density_msgs);
-        };
+  auto log_density_fun = [&](auto&& theta) {
+    return model.template log_prob<true, jacobian, stan::math::var>(
+        theta, &log_density_msgs);
+  };
 
   // calculate inverse negative Hessian's Cholesky factor
   if (refresh > 0) {
@@ -123,7 +121,8 @@ void laplace_sample(const Model& model, const Eigen::VectorXd& theta_hat,
     if (calculate_lp) {
       // clean up created vars after scope exit
       stan::math::nested_rev_autodiff stack;
-      log_p = log_density_fun(unc_draw).val();
+      auto theta = unc_draw.cast<stan::math::var>().eval();
+      log_p = log_density_fun(theta).val();
     } else {
       log_p = std::numeric_limits<double>::quiet_NaN();
     }