# Error operation in integration

**URL:** https://community.freefem.org/t/error-operation-in-integration/293
**Category:** General Discussion
**Created:** [March 7, 2020, 5:03am UTC](https://community.freefem.org/t/error-operation-in-integration/293 "2020-03-07T05:03:10Z")
**Posts on this page:** 1
**Showing post:** 3

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### Author: ![sumantkr](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/sumantkr/32/2681_2.png) [@sumantkr](https://community.freefem.org/u/sumantkr)
#### Post date: [March 12, 2020, 9:24am UTC](https://community.freefem.org/t/error-operation-in-integration/293/3 "2020-03-12T09:24:17Z")

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Thanks for identifying the error,

can we implement the boundary condition of time variable.

like f= 20+30\*t; in Neumann BC or Dirichlet BC, and that would change regularly with time increment.

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