Validation for QuadrilaturalElement

[epsi1on]

add some validation for QuadrilaturalElement

https://github.com/BriefFiniteElementNet/BriefFiniteElement.Net/blob/master/BriefFiniteElementNet.CustomElements/Elements/QuadrilaturalElement.cs

and
https://github.com/BriefFiniteElementNet/BriefFiniteElement.Net/blob/master/BriefFiniteElementNet.CustomElements.Test/QuadrilaturalElementTests.cs

[xyont]

hello, the link above is not active. please updates.

[epsi1on]

QuadElement is in here now (after some replacements)
https://github.com/BriefFiniteElementNet/BriefFiniteElement.Net/tree/master/Sources/CustomElements/Elements
edit: you could also use the search bar on top of page

[epsi1on]

hello, the link above is not active. please updates.

I suggest you to use triangle element, unless you do some validation for quadrilatural results for making sure it works as you do expect. I'm not sure quad element's results are tested yet