(feat) Add ability to save which elements are on old tag

This is usefull to generate sections in BLASTER by identifying upper and lower sides

tbox/src/wMshCrack.cpp

@@ -24,6 +24,8 @@
 #include "wLine2.h"
 #include "wTri3.h"
 
+#include <fstream>
+
 using namespace tbox;
 
 MshCrack::MshCrack(std::shared_ptr<MshData> _msh, int _nDim) : wSharedObject(), msh(_msh), nDim(_nDim)
@@ -337,14 +339,21 @@ void MshCrack::mergeTags(std::vector<Groups *> &grps)
         // Merge tags
         Tag *refTag = gs->groups[0]->tag;
         Tag *oldTag = gs->groups[1]->tag;
+
+        std::vector<int> elems_oldTag;
         // Modify element tags
         for (auto e : gs->groups[1]->tag->elems)
+        {
+            elems_oldTag.push_back(e->no);
             e->ptag = refTag;
+        }
         // Append elements to new tag
         refTag->elems.insert(refTag->elems.end(), oldTag->elems.begin(), oldTag->elems.end());
         // Delete old tag and remove from mesh maps
         msh->ptags.erase(oldTag->no);
         msh->ntags.erase(oldTag->name);
+
+        this->writeElems(elems_oldTag, oldTag->name + ".dat");
         delete oldTag;
     }
 }
@@ -410,3 +419,16 @@ void MshCrack::write(std::ostream &out) const
 {
     out << "MshCrack on " << msh << std::endl;
 }
+
+void MshCrack::writeElems(std::vector<int> const &elmsNo, std::string const filename) const
+{
+    std::ofstream outFile(filename);
+    if (outFile.is_open())
+    {
+        for (const auto &elem : elmsNo)
+            outFile << elem << '\n';
+        outFile.close();
+    }
+    else
+        std::cerr << "Unable to open file: " << filename << std::endl;
+}

tbox/src/wMshCrack.h

@@ -56,6 +56,7 @@ private:
     size_t findClosest(std::vector<Eigen::Vector3d> const &cga, Eigen::Vector3d const &cgb);
     void mergeTags(std::vector<Groups *> &grps);
     void swapNodes(std::vector<Element *> &elms);
+    void writeElems(std::vector<int> const &elmsNo, std::string const filename) const;
 
 public:
     MshCrack(std::shared_ptr<MshData> _msh, int _nDim);