Fix floating pt error in simulation

[teubert]

Fix issue where floating pt errors can occur with very small timesteps sometimes produced by 'auto'

[github-actions[bot]]

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[codecov-commenter]

Codecov Report

Merging #4 (dfe2333) into dev (dfe2333) will not change coverage. The diff coverage is n/a.

:exclamation: Current head dfe2333 differs from pull request most recent head a9eb35a. Consider uploading reports for the commit a9eb35a to get more accurate results

@@           Coverage Diff           @@
##              dev       #4   +/-   ##
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  Coverage   84.17%   84.17%           
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  Files          99       99           
  Lines       10105    10105           
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  Hits         8506     8506           
  Misses       1599     1599