# Material Properties are assigned to 0

**URL:** <https://community.freefem.org/t/material-properties-are-assigned-to-0/827>\
**Category:** General Discussion\
**Created:** [February 25, 2021, 7:49am UTC](https://community.freefem.org/t/material-properties-are-assigned-to-0/827 "2021-02-25T07:49:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Mik](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mik](https://community.freefem.org/u/Mik)\
**Post date:** [February 25, 2021, 7:49am UTC](https://community.freefem.org/t/material-properties-are-assigned-to-0/827/1 "2021-02-25T07:49:12Z")

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Dear Community,

In my thermal problem, I am assigning the material property to 0 at a certain section of my mesh in order to not have any influence of this section in my computation. My code and results everything is perfect thanks to freefem.

However, I have a more general question. As around 20% of my mesh has thermal property as 0, so it might give a highly sparse matrix. Other commercial codes generally crash doing such type of simulation, however, freefem is working perfectly. I wonder what is the justification behind this?

Thanks in advance;

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**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\
**Post date:** [March 1, 2021, 9:10am UTC](https://community.freefem.org/t/material-properties-are-assigned-to-0/827/2 "2021-03-01T09:10:32Z")

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It is hard to given a answer without the math. formulation.