For some test structures the phase error (the difference) between the direct methods phases and the true phases) corresponding to the EXPO traditional Le Bail extraction run (
ERR1) and to the use of the random procedure (ERR2) are given Code
ERR1 ([degrees]) ERR2 ([degrees]) ANDI 29.87 20.68 DADA 48.33 23.32 GAPO 37.18 29.90 LEV 73.55 32.53 UTMI 66.80 23.02 YURI 28.24 22.50 Table 8.
if err1 [much greater than] err2 then {small step size: quick convergence)
else if err1 [is greater than] err2 then {slow convergence}
The value of r is m - 1 or m depending on whether the error estimate err comes from err1 or err2, respectively (see Algorithm 2).