# The elasticity problem with "varf"

**URL:** <https://community.freefem.org/t/the-elasticity-problem-with-varf/2057>\
**Category:** General Discussion\
**Created:** [October 12, 2022, 9:03am UTC](https://community.freefem.org/t/the-elasticity-problem-with-varf/2057 "2022-10-12T09:03:18Z")\
**Posts on this page:** 4\
**Page:** 2

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**Author:** ![SHENG](https://avatars.discourse-cdn.com/v4/letter/s/839c29/32.png) [@SHENG](https://community.freefem.org/u/SHENG)\
**Post date:** [October 19, 2022, 10:03am UTC](https://community.freefem.org/t/the-elasticity-problem-with-varf/2057/21 "2022-10-19T10:03:55Z")

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Sorry professor, I do not understand. Do you mean that In the latest code, I changed the sign in front of all terms linear form, and no sign change in front of the terms in the bilinear form? But the results are wrong, right? Or, you mean that I should change the sign in front of all terms in the right linear form? Sorry Professor, I really do not understand your mean.

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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [October 19, 2022, 10:07am UTC](https://community.freefem.org/t/the-elasticity-problem-with-varf/2057/22 "2022-10-19T10:07:28Z")

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Go back to the files from [The elasticity problem with "varf" - #8 by SHENG](https://community.freefem.org/t/the-elasticity-problem-with-varf/2057/8), and change _only_ the `+` to `-` (and vice versa) in front of linear terms, _not_ bilinear terms. If this still does not work, send your update file.

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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [October 19, 2022, 10:09am UTC](https://community.freefem.org/t/the-elasticity-problem-with-varf/2057/23 "2022-10-19T10:09:29Z")

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If this is not clear to your, linear terms are terms with no references to `u1` or `u2` whatsoever. Please take your time, read your code carefully. There is no magic here, try to understand what you are doing instead of switching signs randomly…

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**Author:** ![SHENG](https://avatars.discourse-cdn.com/v4/letter/s/839c29/32.png) [@SHENG](https://community.freefem.org/u/SHENG)\
**Post date:** [October 19, 2022, 10:13am UTC](https://community.freefem.org/t/the-elasticity-problem-with-varf/2057/24 "2022-10-19T10:13:13Z")

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Ok, professor,

Many thanks for your patient help. I will do that according to your advice.  
Best,  
Liu

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