AsciiDataLayered: remove redundant data_dir

This class is derived from AsciiDataBase that already contains and parses data_directory.

Author: tjhei

include/aspect/structured_data.h

@@ -685,12 +685,6 @@ namespace aspect
         std::vector<std::unique_ptr<aspect::Utilities::StructuredDataLookup<dim-1>>> lookups;
 
       private:
-
-        /**
-         * Directory in which the data files are present.
-         */
-        std::string data_directory;
-
         /**
          * Filenames of data files.
          */

source/structured_data.cc

@@ -1677,20 +1677,6 @@ namespace aspect
 
       prm.enter_subsection (subsection_name);
       {
-        prm.declare_entry ("Data directory",
-                           default_directory,
-                           Patterns::DirectoryName (),
-                           "The name of a directory that contains the model data. This path "
-                           "may either be absolute (if starting with a `/') or relative to "
-                           "the current directory. The path may also include the special "
-                           "text `$ASPECT_SOURCE_DIR' which will be interpreted as the path "
-                           "in which the ASPECT source files were located when ASPECT was "
-                           "compiled. This interpretation allows, for example, to reference "
-                           "files located in the `data/' subdirectory of ASPECT. A trailing "
-                           "slash at the end of the directory path is optional; the plugin "
-                           "will automatically append a '/' when the parameters are parsed if "
-                           "it is missing. ");
-
         prm.declare_entry ("Data file names",
                            default_filename,
                            Patterns::List (Patterns::Anything()),
@@ -1719,10 +1705,6 @@ namespace aspect
 
       prm.enter_subsection(subsection_name);
       {
-        data_directory = Utilities::expand_ASPECT_SOURCE_DIR(prm.get ("Data directory"));
-        // ensure directory ends with a slash so callers can safely do data_directory + filename
-        if (!data_directory.empty() && data_directory.back() != '/')
-          data_directory.push_back('/');
         data_file_names = Utilities::split_string_list(prm.get ("Data file names"), ',');
         interpolation_scheme = prm.get("Interpolation scheme");
       }