, ÿÿÿÿ 9S    @  @      í   /    differentiate_center2 1  0ff_dx_sf        `  ff_dx_sf
    @  €                        var
 A      €                       ff_dz_fs         `  ff_dz_fs
    @  €                        var
 A      €                       sf_dz_ss         `  sf_dz_ss
    @  €                        var
 A      €                       sf_dx_ff         `  sf_dx_ff
    @  €                        var
 A      €                       fs_dz_ff         `  fs_dz_ff
    @  €                        var
 A      €                       fs_dx_ss         `  fs_dx_ss
    @  €                        var
 A      €                       ss_dz_sf         `  ss_dz_sf
    @  €                        var
 A      €                       ss_dx_fs         `  ss_dx_fs
    @  €                        var
 A      €                        $ ff_dx_sfff_dx_sfff_dx_sfdifferentiate_center2  $ ff_dz_fsff_dz_fsff_dz_fsdifferentiate_center2  $ sf_dz_sssf_dz_sssf_dz_ssdifferentiate_center2  $ sf_dx_ffsf_dx_ffsf_dx_ffdifferentiate_center2  $ fs_dz_fffs_dz_fffs_dz_ffdifferentiate_center2  $ fs_dx_ssfs_dx_ssfs_dx_ssdifferentiate_center2  $ ss_dz_sfss_dz_sfss_dz_sfdifferentiate_center2  $ ss_dx_fsss_dx_fsss_dx_fsdifferentiate_center2  