[petsc-users] basis functions of high order approximation (FE)

Yann Jobic yann.jobic at univ-amu.fr
Tue Jan 8 03:31:58 CST 2019


Dear Petsc Users,

I've been playing with the option "space_degree", in 2D, for a space 
discretisation of 4 cells (2x2), for a poisson problem, and i wonder 
what are the underlying concepts.

With a space degree 2, i get a    9x9   algebraic system, and i've got a 
solution convergence order of 3.

With a space degree 3, i get a 25x25 algebraic system, and i've got a 
solution convergence order of 4.

So my question is : what are the basis functions associated with each 
space degree ?

Are they lagrange polynomials or something else ?

Thanks!

Yann



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