step size too small

G. Perhar
  • G. Perhar

    G. Perhar - 2008-05-26

    Hello all.

    I'm running a system of five differential equations, and when computing bifurcation diagrams, some parameterizations return an error message reading: "step size too small"

    Question: is this my model crashing, or can i tweak some settings to correct this?

    I have played with the three step size settings, but it always happens at the same spot, with the same parameter values.

    Any help and all feedback is greatly appreciated!

    • Govaerts

      Govaerts - 2008-05-27

      Dear colleague,

      The message means that a (pseudo-) Newton iteration has failed to converge. There can be many reasons for this, but there is a good chance that you can solve the problem by relaxing the constraints on convergence, i.e. by increasing the values of FunTolerance, VarTolerance or both.

      Best regards,

      Willy Govaerts

  • mik2562

    mik2562 - 2011-06-03


    i have a similar problem continuing a LPC-line from a GH-point in a three equation fitzhugh-nagumo model.
    i didn't succeed by increasing the tolerances and varying the minimal step size.
    is there a chance to fix this somehow?
    if not, what could be the reasons?

    kind regards,

  • EdR

    EdR - 2011-08-18

    I have had the same exact issue and am not sure how to proceed. Tried varying all the tolerances and the minimal step size, but to no avail. Is there any way to fix this?


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