Add fallback for numerically unstable triple points.

This change modifies the LinearInterfaceCalculator to fallback to
computing triple points as barycentric points when the indicator
function produces numerically unstable coordinates.

TetMesh angles output now only prints out degenerate tetes.
Previously, it printed all tets after the first degenerate tet.
Additionally, the number of bad tets is printed in the summary.

src/lib/cleaver/LinearInterfaceCalculator.cpp

@@ -324,11 +324,9 @@ void LinearInterfaceCalculator::computeTripleForFace(HalfFace *face) {
     bool success = planeIntersect(v1, v2, v3, origin, ray, result);
     if (!success)
     {
-      //std::cout << "Failed to Project Triple BACK into 3D: Using Barycenter" << std::endl;
-      //result = (1.0/3.0)*(v1->pos() + v2->pos() + v3->pos());
-      //axis = 2;
-      std::cout << "Failed Axis==1, the most likely candidate to succeeed..." << std::endl;
-      exit(0);
+      std::cout << "Numerical Failure projecting triple into 3D: Fall back to Barycenter" << std::endl;
+      result = (1.0/3.0)*(v1->pos() + v2->pos() + v3->pos());
+      // std::cout << "Failed Axis==1, the most likely candidate to succeeed..." << std::endl;
     }
 
   } else if (axis == 2)
@@ -378,9 +376,9 @@ void LinearInterfaceCalculator::computeTripleForFace(HalfFace *face) {
     bool success = planeIntersect(v1, v2, v3, origin, ray, result);
     if (!success)
     {
-      //axis = 3;
-      std::cout << "Failed Axis==2, the most likely candidate to succeeed..." << std::endl;
-      exit(0);
+      std::cout << "Numerical Failure projecting triple into 3D: Fall back to Barycenter" << std::endl;
+      result = (1.0/3.0)*(v1->pos() + v2->pos() + v3->pos());
+      // std::cout << "Failed Axis==2, the most likely candidate to succeeed..." << std::endl;
     }
   } else if (axis == 3)
   {
@@ -429,8 +427,9 @@ void LinearInterfaceCalculator::computeTripleForFace(HalfFace *face) {
     bool success = planeIntersect(v1, v2, v3, origin, ray, result);
     if (!success)
     {
-      std::cout << "Failed Axis==3, the most likely candidate to succeeed..." << std::endl;
-      exit(0);
+      std::cout << "Numerical Failure projecting triple into 3D: Fall back to Barycenter" << std::endl;
+      result = (1.0/3.0)*(v1->pos() + v2->pos() + v3->pos());
+      // std::cout << "Failed Axis==3, the most likely candidate to succeeed..." << std::endl;
     }
   }
 

src/lib/cleaver/TetMesh.cpp

@@ -1149,7 +1149,7 @@ namespace cleaver
       }
 
       // DEBUG for flat tets
-      if(max == 180){
+      if(local_max == 180){
         if (bad_tets > 0)
           debug_dump << "," << std::endl;
         bad_tets++;
@@ -1180,6 +1180,9 @@ namespace cleaver
     debug_dump << "]}" << std::endl;
     debug_dump.close();
     status.done();
+    if (bad_tets > 0) {
+      std::cout << "Errors: " << bad_tets << " degenerate tets." << std::endl;
+    }
 
     min_angle = min;
     max_angle = max;