From 5556db54200d19e453b87b7ba2eea1da106f3b78 Mon Sep 17 00:00:00 2001
From: Binit Shah <binitpshah@gmail.com>
Date: Sat, 30 May 2020 17:35:22 -0400
Subject: [PATCH] Using optional sampler outside loop

---
 gtsam/slam/dataset.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/gtsam/slam/dataset.cpp b/gtsam/slam/dataset.cpp
index 0ed958869..66e8fc4c0 100644
--- a/gtsam/slam/dataset.cpp
+++ b/gtsam/slam/dataset.cpp
@@ -37,6 +37,7 @@
 #include <boost/assign/list_inserter.hpp>
 #include <boost/filesystem/operations.hpp>
 #include <boost/filesystem/path.hpp>
+#include <boost/optional.hpp>
 
 #include <cmath>
 #include <fstream>
@@ -546,6 +547,11 @@ BetweenFactorPose3s parse3DFactors(const string& filename,
   ifstream is(filename.c_str());
   if (!is) throw invalid_argument("parse3DFactors: can not find file " + filename);
 
+  boost::optional<Sampler> sampler;
+  if (corruptingNoise) {
+    sampler = Sampler(corruptingNoise);
+  }
+
   std::vector<BetweenFactor<Pose3>::shared_ptr> factors;
   while (!is.eof()) {
     char buf[LINESIZE];
@@ -587,9 +593,8 @@ BetweenFactorPose3s parse3DFactors(const string& filename,
 
       SharedNoiseModel model = noiseModel::Gaussian::Information(mgtsam);
       auto R12 = Rot3::Quaternion(qw, qx, qy, qz);
-      if (corruptingNoise) {
-        Sampler sampler(corruptingNoise);
-        R12 = R12.retract(sampler.sample());
+      if (sampler) {
+        R12 = R12.retract(sampler->sample());
       }
 
       factors.emplace_back(new BetweenFactor<Pose3>(