text: 
  #include "LTF/LTF.h"
  
  #include <fstream>
  #include <string>
  #include <vector>
  #include <map>
  #include <set>
  
  class LTF_Tools {
  public:
  
  // _____________________________________________________________________________________ //
  //! 
  //!  read_correlations
  //!
  //!  Read a matrix from a simple ascii file
  //!
  static
     std::vector<std::vector<double > > read_correlations(std::string filename, int ncol, bool DoCorrTest=false);
  
  
  // _____________________________________________________________________________________ //
  //! 
  //!  corr_to_cov
  //!
  //!  calculate a covariance matrix from a correlation matrix and uncertainties
  //!
  static
  std::vector<std::vector<double > > corr_to_cov( const std::vector<std::vector<double > >& corr, const std::vector<double >& percenterr, const std::vector<double >& data);
  
  
  // _____________________________________________________________________________________ //
  //! 
  //!  read_input_table
  //!
  //! read input data table from file and return it as a map
  //!
  static
  std::map < std::string, std::vector<double> > read_input_table(std::string filename, int ncol );
  
  };
  