From 995bedb4ca947b599300813d7e91eeec7b8c391b Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Fri, 16 May 2025 23:59:27 -0400
Subject: [PATCH] use default RNG object for mt19937_64 everywhere

---
 gtsam/linear/GaussianBayesNet.cpp | 12 ------------
 gtsam/linear/GaussianBayesNet.h   | 10 ++--------
 gtsam/linear/linear.i             | 12 +++++++-----
 3 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/gtsam/linear/GaussianBayesNet.cpp b/gtsam/linear/GaussianBayesNet.cpp
index f8c4ddc4c..aa11ca911 100644
--- a/gtsam/linear/GaussianBayesNet.cpp
+++ b/gtsam/linear/GaussianBayesNet.cpp
@@ -26,9 +26,6 @@
 using namespace std;
 using namespace gtsam;
 
-// In Wrappers we have no access to this so have a default ready
-static std::mt19937_64 kRandomNumberGenerator(42);
-
 namespace gtsam {
 
   // Instantiate base class
@@ -76,15 +73,6 @@ namespace gtsam {
     return result;
   }
 
-  /* ************************************************************************ */
-  VectorValues GaussianBayesNet::sample() const {
-    return sample(&kRandomNumberGenerator);
-  }
-
-  VectorValues GaussianBayesNet::sample(const VectorValues& given) const {
-    return sample(given, &kRandomNumberGenerator);
-  }
-
   /* ************************************************************************ */
   VectorValues GaussianBayesNet::optimizeGradientSearch() const
   {
diff --git a/gtsam/linear/GaussianBayesNet.h b/gtsam/linear/GaussianBayesNet.h
index 538d1532e..8d22826f8 100644
--- a/gtsam/linear/GaussianBayesNet.h
+++ b/gtsam/linear/GaussianBayesNet.h
@@ -131,7 +131,7 @@ namespace gtsam {
      *   std::mt19937_64 rng(42);
      *   auto sample = gbn.sample(&rng);
      */
-    VectorValues sample(std::mt19937_64* rng) const;
+    VectorValues sample(std::mt19937_64* rng = nullptr) const;
 
     /**
      * Sample from an incomplete BayesNet, given missing variables
@@ -140,13 +140,7 @@ namespace gtsam {
      *   VectorValues given = ...;
      *   auto sample = gbn.sample(given, &rng);
      */
-    VectorValues sample(const VectorValues& given, std::mt19937_64* rng) const;
-
-    /// Sample using ancestral sampling, use default rng
-    VectorValues sample() const;
-
-    /// Sample from an incomplete BayesNet, use default rng
-    VectorValues sample(const VectorValues& given) const;
+    VectorValues sample(const VectorValues& given, std::mt19937_64* rng = nullptr) const;
 
     /**
      * Return ordering corresponding to a topological sort.
diff --git a/gtsam/linear/linear.i b/gtsam/linear/linear.i
index dcd6c6f3f..6f4524b27 100644
--- a/gtsam/linear/linear.i
+++ b/gtsam/linear/linear.i
@@ -560,8 +560,9 @@ virtual class GaussianConditional : gtsam::JacobianFactor {
       const gtsam::VectorValues& frontalValues) const;
   gtsam::JacobianFactor* likelihood(gtsam::Vector frontal) const;
 
-  gtsam::VectorValues sample(std::mt19937_64@ rng = nullptr) const;
-  gtsam::VectorValues sample(const gtsam::VectorValues& parents, std::mt19937_64@ rng = nullptr) const;
+  gtsam::VectorValues sample(std::mt19937_64 @rng = nullptr) const;
+  gtsam::VectorValues sample(const gtsam::VectorValues& parents,
+                             std::mt19937_64 @rng = nullptr) const;
 
   // Advanced Interface
   gtsam::VectorValues solveOtherRHS(const gtsam::VectorValues& parents,
@@ -627,9 +628,10 @@ virtual class GaussianBayesNet {
   gtsam::VectorValues optimize() const;
   gtsam::VectorValues optimize(const gtsam::VectorValues& given) const;
   gtsam::VectorValues optimizeGradientSearch() const;
-  
-  gtsam::VectorValues sample(const gtsam::VectorValues& given) const;
-  gtsam::VectorValues sample() const;
+
+  gtsam::VectorValues sample(const gtsam::VectorValues& given,
+                             std::mt19937_64 @rng = nullptr) const;
+  gtsam::VectorValues sample(std::mt19937_64 @rng = nullptr) const;
   gtsam::VectorValues backSubstitute(const gtsam::VectorValues& gx) const;
   gtsam::VectorValues backSubstituteTranspose(const gtsam::VectorValues& gx) const;