addressed final comments by Frank

gtsam/nonlinear/GncOptimizer.h

@@ -57,39 +57,25 @@ class GncOptimizer {
       if (graph[i]) {
         NoiseModelFactor::shared_ptr factor = boost::dynamic_pointer_cast<
             NoiseModelFactor>(graph[i]);
-        noiseModel::Robust::shared_ptr robust = boost::dynamic_pointer_cast<
+        auto robust = boost::dynamic_pointer_cast<
             noiseModel::Robust>(factor->noiseModel());
-        if (robust) {  // if the factor has a robust loss, we have to change it:
+        // if the factor has a robust loss, we remove the robust loss
-          SharedNoiseModel gaussianNoise = robust->noise();
+        nfg_[i] = robust ? factor-> cloneWithNewNoiseModel(robust->noise()) : factor;
-          NoiseModelFactor::shared_ptr gaussianFactor = factor
-              ->cloneWithNewNoiseModel(gaussianNoise);
-          nfg_[i] = gaussianFactor;
-        } else {  // else we directly push it back
-          nfg_[i] = factor;
-        }
       }
     }
   }
 
   /// Access a copy of the internal factor graph.
-  NonlinearFactorGraph getFactors() const {
+  const NonlinearFactorGraph& getFactors() const { return nfg_; }
-    return NonlinearFactorGraph(nfg_);
-  }
 
   /// Access a copy of the internal values.
-  Values getState() const {
+  const Values& getState() const { return state_; }
-    return Values(state_);
-  }
 
   /// Access a copy of the parameters.
-  GncParameters getParams() const {
+  const GncParameters& getParams() const { return params_;}
-    return GncParameters(params_);
-  }
 
   /// Access a copy of the GNC weights.
-  Vector getWeights() const {
+  const Vector& getWeights() const { return weights_;}
-    return weights_;
-  }
 
   /// Compute optimal solution using graduated non-convexity.
   Values optimize() {
@@ -279,15 +265,14 @@ class GncOptimizer {
     newGraph.resize(nfg_.size());
     for (size_t i = 0; i < nfg_.size(); i++) {
       if (nfg_[i]) {
-        NoiseModelFactor::shared_ptr factor = boost::dynamic_pointer_cast<
+        auto factor = boost::dynamic_pointer_cast<
             NoiseModelFactor>(nfg_[i]);
-        noiseModel::Gaussian::shared_ptr noiseModel =
+        auto noiseModel =
             boost::dynamic_pointer_cast<noiseModel::Gaussian>(
                 factor->noiseModel());
         if (noiseModel) {
           Matrix newInfo = weights[i] * noiseModel->information();
-          SharedNoiseModel newNoiseModel = noiseModel::Gaussian::Information(
+          auto newNoiseModel = noiseModel::Gaussian::Information(newInfo);
-              newInfo);
           newGraph[i] = factor->cloneWithNewNoiseModel(newNoiseModel);
         } else {
           throw std::runtime_error(

gtsam/nonlinear/GncParams.h

@@ -77,6 +77,7 @@ class GncParams {
   void setLossType(const GncLossType type) {
     lossType = type;
   }
+
   /// Set the maximum number of iterations in GNC (changing the max nr of iters might lead to less accurate solutions and is not recommended).
   void setMaxIterations(const size_t maxIter) {
     std::cout
@@ -84,6 +85,7 @@ class GncParams {
         << std::endl;
     maxIterations = maxIter;
   }
+
   /** Set the maximum weighted residual error for an inlier. For a factor in the form f(x) = 0.5 * || r(x) ||^2_Omega,
    * the inlier threshold is the largest value of f(x) for the corresponding measurement to be considered an inlier.
    * In other words, an inlier at x is such that 0.5 * || r(x) ||^2_Omega <= barcSq.
@@ -93,22 +95,27 @@ class GncParams {
   void setInlierCostThreshold(const double inth) {
     barcSq = inth;
   }
+
   /// Set the graduated non-convexity step: at each GNC iteration, mu is updated as mu <- mu * muStep.
   void setMuStep(const double step) {
     muStep = step;
   }
+
   /// Set the maximum relative difference in mu values to stop iterating.
   void setRelativeCostTol(double value) {
     relativeCostTol = value;
   }
+
   /// Set the maximum difference between the weights and their rounding in {0,1} to stop iterating.
   void setWeightsTol(double value) {
     weightsTol = value;
   }
+
   /// Set the verbosity level.
   void setVerbosityGNC(const Verbosity value) {
     verbosity = value;
   }
+
   /** (Optional) Provide a vector of measurements that must be considered inliers. The enties in the vector
    * corresponds to the slots in the factor graph. For instance, if you have a nonlinear factor graph nfg,
    * and you provide  knownIn = {0, 2, 15}, GNC will not apply outlier rejection to nfg[0], nfg[2], and nfg[15].
@@ -119,6 +126,7 @@ class GncParams {
     for (size_t i = 0; i < knownIn.size(); i++)
       knownInliers.push_back(knownIn[i]);
   }
+
   /// Equals.
   bool equals(const GncParams& other, double tol = 1e-9) const {
     return baseOptimizerParams.equals(other.baseOptimizerParams)
@@ -127,6 +135,7 @@ class GncParams {
         && std::fabs(muStep - other.muStep) <= tol
         && verbosity == other.verbosity && knownInliers == other.knownInliers;
   }
+
   /// Print.
   void print(const std::string& str) const {
     std::cout << str << "\n";