def update_config(self):
        """
        Update the configuration files according to the current
        in-memory SExtractor configuration.
        """

        # -- Write filter configuration file

        # First check the filter itself

        filter = self.config['FILTER_MASK']
        rows = len(filter)
        cols = len(filter[0])   # May raise ValueError, OK

        filter_f = __builtin__.open(self.config['FILTER_NAME'], 'w')
        filter_f.write("CONV NORM\n")
        filter_f.write("# %dx%d Generated from sextractor.py module.\n" %
                       (rows, cols))
        for row in filter:
            filter_f.write(" ".join(map(repr, row)))
            filter_f.write("\n")

        filter_f.close()

        # -- Write parameter list file

        parameters_f = __builtin__.open(self.config['PARAMETERS_NAME'], 'w')
        for parameter in self.config['PARAMETERS_LIST']:
            print(parameter, file=parameters_f)

        parameters_f.close()

        # -- Write NNW configuration file

        nnw_f = __builtin__.open(self.config['STARNNW_NAME'], 'w')
        nnw_f.write(nnw_config)
        nnw_f.close()

        # -- Write main configuration file

        main_f = __builtin__.open(self.config['CONFIG_FILE'], 'w')

        for key in self.config.keys():
            if (key in SExtractor._SE_config_special_keys):
                continue

            if (key == "PHOT_AUTOPARAMS"):  # tuple instead of a single value
                value = " ".join(map(str, self.config[key]))
            else:
                value = str(self.config[key])

            print(("%-16s       %-16s # %s" % (key, value, SExtractor._SE_config[key]['comment'])), file=main_f)

        main_f.close()
Update the configuration files according to the current
        in-memory SExtractor configuration.