From f2c086ccaf78f4df274ac5784771c942a477926f Mon Sep 17 00:00:00 2001
From: regislebrun <regis.lebrun@m4x.org>
Date: Sun, 10 Dec 2023 16:30:18 +0100
Subject: [PATCH] Cosmetic

Slightly simplified LevelSetMesher logic
---
 lib/src/Base/Geom/LevelSetMesher.cxx | 37 ++++++++--------------------
 1 file changed, 10 insertions(+), 27 deletions(-)

diff --git a/lib/src/Base/Geom/LevelSetMesher.cxx b/lib/src/Base/Geom/LevelSetMesher.cxx
index 35af9a96f9..2767dd41a3 100644
--- a/lib/src/Base/Geom/LevelSetMesher.cxx
+++ b/lib/src/Base/Geom/LevelSetMesher.cxx
@@ -242,47 +242,30 @@ Mesh LevelSetMesher::build(const LevelSet & levelSet,
                 OptimizationAlgorithm solver(solver_);
                 solver.setStartingPoint(delta);
                 solver.setProblem(problem);
-                OptimizationResult result;
-                // Here we have to catch exceptions raised by the gradient
+                // Here we have to catch exceptions raised by the algorithm (may be due to e.g the gradient)
                 try
                 {
                   solver.run();
-                  result = solver.getResult();
+                  movedVertices.add(currentVertex + solver.getResult().getOptimalPoint());
                 }
                 catch(...)
                 {
-                  LOGDEBUG(OSS() << "Problem to project point=" << currentVertex << " with solver=" << solver_ << ", using finite differences for gradient");
-                  // Here we may have to fix the gradient eg in the case of analytical functions, when Ev3 does not handle the expression.
-                  const Scalar epsilon = ResourceMap::GetAsScalar("CenteredFiniteDifferenceGradient-DefaultEpsilon");
-                  levelFunction.setGradient(CenteredFiniteDifferenceGradient((localVertices.getMin() - localVertices.getMax()) * epsilon + Point(dimension, epsilon), levelFunction.getEvaluation()).clone());
-                  problem.setLevelFunction(levelFunction);
-                  solver.setProblem(problem);
-                  // Try with the new gradients
+                  // There is a problem with this vertex. Try a gradient-free solver
+                  Cobyla cobyla(solver.getProblem());
+                  cobyla.setStartingPoint(delta);
+                  LOGDEBUG(OSS() << "Problem to project point=" << currentVertex << " with solver=" << solver << " and finite differences for gradient, switching to solver=" << cobyla);
                   try
-                  {
-                    solver.run();
-                    result = solver.getResult();
-                    movedVertices.add(currentVertex + result.getOptimalPoint());
-                  }
-                  catch(...)
-                  {
-                    // There is definitely a problem with this vertex. Try a gradient-free solver
-                    Cobyla cobyla(solver.getProblem());
-                    cobyla.setStartingPoint(solver.getStartingPoint());
-                    LOGDEBUG(OSS() << "Problem to project point=" << currentVertex << " with solver=" << solver << " and finite differences for gradient, switching to solver=" << cobyla);
-                    try
                     {
                       cobyla.run();
-                      result = cobyla.getResult();
-                      movedVertices.add(currentVertex + result.getOptimalPoint());
+                      movedVertices.add(currentVertex + cobyla.getResult().getOptimalPoint());
                     }
-                    catch(...)
+                  catch(...)
                     {
                       LOGDEBUG(OSS() << "Problem to project point=" << currentVertex << " with solver=" << cobyla << ", use basic linear interpolation");
                       movedVertices.add(currentVertex + delta);
                     }
-                  } // Even finite differences gradient failed?
-                } // Gradient failed ?
+                } // User-defined solver failed ?
+                // Restore the use of solve-the-equation if we used minimization due to a difficult vertex
                 minimizeDistance = !solveEquation;
               } // minimizeDistance
             } // project