4 Tool functions
  
  
  4.1 Read and write matrix
  
  4.1-1 4ti2Interface_Read_Matrix_From_File
  
  4ti2Interface_Read_Matrix_From_File( arg )  function
  Returns:  a list of vectors
  
  The  argument must be a string, representing a filename of a matrix to read.
  Numbers  must  be seperated by whitespace, and the first two numbers must be
  the number of rows and columns. The function then returns the matrix as list
  of lists.
  
  4.1-2 4ti2Interface_Write_Matrix_To_File
  
  4ti2Interface_Write_Matrix_To_File( arg )  function
  Returns:  nothing
  
  First  argument  must  be  a matrix, i.e. a list of list of integers. Second
  argument  has  to  be a filename. The method stores the matrix in this file,
  seperated  by whitespace, line by line. The content of the file, if there is
  any, will be deleted.
  
  4.1-3 4ti2Interface_Cut_Vector
  
  4ti2Interface_Cut_Vector( vec, d )  function
  Returns:  a matrix
  
  Takes the vector vec and produces a matrix with d columns out of the entries
  of the vector.