added flexibility

src/utils/io.cpp

@@ -193,3 +193,33 @@ void save_data_to_file(
         }
     }
 }
+
+void save_data_to_file(
+    const std::string& resulttype,
+    const std::string& motiontype,
+    const std::string& disttype,
+    const std::vector<double>& x,
+    const std::vector<double>& y,
+    std::unordered_map<std::string, double>& optional
+    ) {
+    // make file name
+    std::ostringstream datafile_name;
+    datafile_name << resulttype << "_" << motiontype << "_" << disttype;
+    datafile_name << std::setprecision(6) << std::scientific;
+    for (const auto& [key, value]: optional) {
+        datafile_name << "_" << key << "=" << value;
+    }
+    datafile_name << ".dat";
+
+    {
+        // write data to file, columns are secondary axis (echo delay, evolution times)
+        std::string datafile = datafile_name.str();
+        std::ofstream filestream(datafile, std::ios::out);
+
+        // write values to file
+        auto size = x.size();
+        for (unsigned int i = 0; i < size; i++) {
+            filestream << x[i] << "\t" << y[i] << "\n";
+        }
+    }
+}