Note that convergence will usually only take 10 to 20 iterations if the starting model is reasonable. The largest relative change in that will be accepted as showing that the process has converged. Other criteria must also be met so that the program is sure that a true minimum has been reached. The distance in scaled parameter space that is used to test whether the parameters are close enough to their optimum values for the process to have converged. The scaling factors vary dynamically during the fit so this value can not be set from a set of accuracy requirements.
Large numbers are less stringent.
A parameter used in the false convergence test. Smaller numbers make false convergence less likely but the default value is only 100 times the machine precision, giving little scope for significant reductions. Click on OK or Apply to make any changes take effect. The dialogue will be dismissed if you click on OK but will remain in place if you click on Apply . Click on Cancel to dismiss the dialogue without changing the convergence parameters.