check_layout_generation
                        This is a wrapper function of check layout
                        generation
density_check           Internal function for density check of check
                        layout
diagSet_check_by_density
                        Generate a spatial layout of checks by diagonal
                        design (settle for density = .1 - .35
diag_extract            Extract the designed diagonal pattern from the
                        system data file (Internal functions)
diagonal_check_by_density
                        Generate a spatial layout of checks by diagonal
                        design
equal_check_by_plot     Generate a spatial layout of checks by every #
                        of plots
equal_space_check_by_density
                        Generate a spatial layout of checks by density
iso_simulation_by_heriability
                        A simulation fucntion for isotrophic spatial
                        data
iso_simulation_p_rep    A simulation fucntion for isotrophic spatial
                        data wrt/ p-rep data
iso_spatial_cov         Isotropic spatial var-cov wrapper
iso_spatial_exp         Isotropic spatial simulation by exponential
                        function
iso_spatial_floor       Isotropic spatial simulation wrapper
iso_spatial_gau         Isotropic spatial simulation by Gaussian
                        function
p_rep_check_by_density
                        Generate a spatial layout of checks by density:
                        p rep design with checks
random_check_by_density
                        Generate a random spatial layout of check
spatial_dist            Distance matrix calculation
