# Back and forth on step length never finished

**URL:** <https://forum.dynare.org/t/back-and-forth-on-step-length-never-finished/11117>\
**Category:** Dynare help (legacy posts)\
**Created:** [16 December 2017 18:30 UTC](https://forum.dynare.org/t/back-and-forth-on-step-length-never-finished/11117 "2017-12-16T18:30:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Leonid\_65](https://forum.dynare.org/letter_avatar_proxy/v4/letter/l/85e7bf/32.png) [@Leonid\_65](https://forum.dynare.org/u/Leonid_65)\
**Post date:** [16 December 2017 18:30 UTC](https://forum.dynare.org/t/back-and-forth-on-step-length-never-finished/11117/1 "2017-12-16T18:30:17Z")

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Hi Prof. Pfeifer and to all,  
What does it mean when evaluating parameters in a Dynare lines “smallest step still improving too slow”,  
and “back and forth on step length never finished”?  
How critical is this?  
I really appreciate any help you can provide.

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**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\
**Post date:** [16 December 2017 20:08 UTC](https://forum.dynare.org/t/back-and-forth-on-step-length-never-finished/11117/2 "2017-12-16T20:08:27Z")

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That means your mode-finder did not terminate with a proper exit code that would suggest a minimum. That might be an issue. You need to check the mode\_check plots and the convergence diagnostics.