Algorithm 1.

Fine-to-coarse mesh refinement

Initialize set of coarse mesh elements C with tetrahedral elements from mesh generation

for each c ∈ C do

compute V(c), the volume of c

compute N(c), the list of nearest neighbors of c

initialize L(c), the list of tetrahedral elements comprising   c

end for

for each c ∈ C such that V (c) < Vt do

Merge c with the member of N(c) with the largest   volume, m

Remove c from C

Update N(m) to include N(c):

Update members of N(c) to include m

Update members of N(c) to remove c

Update V (m) = V (c) + V (m)

Update L(m) = L(m) ∪ L(c)

end for