Move the function reading input data to a filereader.hh

dune/gfe/filereader.hh

+#ifndef DUNE_GFE_FILEREADER_HH
+#define DUNE_GFE_FILEREADER_HH
+
+#include <iostream>
+#include <fstream>
+
+#include <dune/common/fvector.hh>
+// This is a custom file format parser which reads in a grid deformation file
+// The file must contain lines of the format <grid vertex>:<displacement or rotation>
+// !!! THIS IS A TEMPORARY SOLUTION AND WILL BE REPLACED BY THE Dune::VtkReader in dune-vtk/dune/vtk/vtkreader.hh !!!
+namespace Dune {
+  namespace GFE {
+    // Convert the pairs {grid vertex, vector of dimension d} in the given file to a map
+    template <int d>
+    static std::unordered_map<std::string, FieldVector<double,d>> transformFileToMap(std::string pathToFile) {
+
+        std::unordered_map<std::string, FieldVector<double,d>> map;
+
+        std::string line, displacement, entry;
+
+        std::ifstream file(pathToFile, std::ios::in);
+
+        if (file.is_open()) {
+          while (std::getline(file, line)) {
+            size_t j = 0;
+            size_t pos = line.find(":");
+            displacement = line.substr(pos + 1);
+            line.erase(pos);
+            std::stringstream entries(displacement);
+            FieldVector<double,d> vector(0);
+            while(entries >> entry)
+              vector[j++] = std::stod(entry);
+            map.insert({line,vector});
+          }
+          file.close();
+        } else {
+          DUNE_THROW(Exception, "Error: Could not open the file " + pathToFile + " !");
+        }
+      return map;
+    }
+  }
+}
+#endif
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