# Increment time control/setting

**URL:** <https://prepomax.discourse.group/t/increment-time-control-setting/338>\
**Category:** General Questions\
**Created:** [August 4, 2022, 1:25am UTC](https://prepomax.discourse.group/t/increment-time-control-setting/338 "2022-08-04T01:25:52Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![PaoPao1970](https://avatars.discourse-cdn.com/v4/letter/p/d9b06d/32.png) [@PaoPao1970](https://prepomax.discourse.group/u/PaoPao1970)\
**Post date:** [August 4, 2022, 1:25am UTC](https://prepomax.discourse.group/t/increment-time-control-setting/338/1 "2022-08-04T01:25:52Z")

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I would like to set increment time as follows  
Increment time is 0.005 at 0.25~0.40 and 0.60~0.75  
Because this area is easy to occur calculation error  
Could you help me how to setting ?

 ![increment](https://global.discourse-cdn.com/free1/uploads/prepomax/original/1X/e891edb446f9bc5cc0a041f19914132a9a916e75.jpeg)

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [August 4, 2022, 7:00am UTC](https://prepomax.discourse.group/t/increment-time-control-setting/338/2 "2022-08-04T07:00:32Z")

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With the default automatic incrementation CalculiX will adjust the increment size based on convergence. Fixed incrementation is usually not recommended. However, you can request output at specific time points for increased accuracy around a specific moment in time. Use the \*TIME POINTS keyword for this purpose.

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<div class="post-metadata">

**Author:** ![PaoPao1970](https://avatars.discourse-cdn.com/v4/letter/p/d9b06d/32.png) [@PaoPao1970](https://prepomax.discourse.group/u/PaoPao1970)\
**Post date:** [August 21, 2022, 12:49pm UTC](https://prepomax.discourse.group/t/increment-time-control-setting/338/3 "2022-08-21T12:49:34Z")

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“Automatic” is set on Incrementation  
“Max time increment” of my analysis model need 0.005s  
If 0.01 set , prepomax will occur convergence error.  
Time period is 1 s  
Convergence error occur 0.25~0.40 and 0.60~0.75 period.  
therefore i would like to set “Max time increment 0.005” among 0.25~0.40 and 0.60~0.75  
But i would like to short total analysis total time.  
Therefore i would like to set “Max time increment 0.01” among 0.0~0.25 and 0.40~0.60 and 0.75~1.0

 ![Max_time_increment](https://global.discourse-cdn.com/free1/uploads/prepomax/original/1X/b864503f7c9ebbd5049c775ac7df85463c78c9f9.jpeg)

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<div class="post-metadata">

**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [August 22, 2022, 9:54am UTC](https://prepomax.discourse.group/t/increment-time-control-setting/338/4 "2022-08-22T09:54:02Z")

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CalculiX should use the maximum increment only if convergence is good enough to allow for this. Minimum time increment is used if convergence is really poor. So theoretically, the solver should drop the time increment down (but not lower than allowed by minimum time increment) when it encounters convergence issues and raise it (but not higher than allowed by maximum time increment) when convergence behavior improves. However, there seems to be an issue with minimum time increment definitions: [Minimum time increment can't be lower than 1e-5 - CalculiX](https://calculix.discourse.group/t/minimum-time-increment-cant-be-lower-than-1e-5/1201)

Also, you should be careful with max increments value - CalculiX won’t exceed the number of increments specified there so it’s often better to increase it to e.g. 1000.