[ANN] Gridap.jl: A feature-rich Finite Element ecosystem 100% in Julia

The answer is yes, yes.

For periodic conditions (now only for Cartesian meshes)

dimain = (0,1,0,1,0,0.01)
cells = (4,4,3)
model = CartesianDiscreteModel(domain,cells;isperiodic=(false,false,true))

For linear DOF constraints:

https://github.com/gridap/Gridap.jl/blob/master/test/FESpacesTests/FESpacesWithLinearConstraintsTests.jl

hope it helps