Write data set to file
brif_write_data(df, resp_col_num = 1, outfile = "data")
a list of four elements. n: number of rows, p: number of predictors, data_file: name of the data file, config_file: name of the configuration file
a data frame
an integer indicating the column number (in df) of the response variable. For test data without the response column, use 0 here.
a character string specifying the file name prefix of output files