Fix case value is negative due to numeric instability

micmacIGN · Aug 21, 2024 · 991dfed · 991dfed
1 parent 5e30bc4
commit 991dfed
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/MMVII/src/Geom3D/GeomsBase3D.cpp b/MMVII/src/Geom3D/GeomsBase3D.cpp
@@ -548,8 +548,9 @@ tREAL8 L2_DegenerateIndex(const std::vector<cPt3dr> & aVPt,size_t aNumEigV)
             aStat.Add(aP3.ToVect());
     aStat.Normalise();
     const cDenseVect<tREAL8> anEV = aStat.DoEigen().EigenValues() ;
-
-    if (anEV(2)==0)  return 0.0;
+    // theoretically eigenvalues can't be negavive => treat <0 as =0
+    if (anEV(2)<=0)  return 0.0;
+    if (anEV(aNumEigV)<0)  return 0.0;
 
     return Sqrt(SafeDiv(anEV(aNumEigV),anEV(2)));
 }