Subdivision mask
= Subdivision mask
{title2=$q_j=\sum_i a_{j-2i}p_i$}
A stationary binary <subdivision mask> $a$ specifies a refinement operator $q_j=\sum_i a_{j-2i}p_i$. Indices may be vectors for a surface. Coefficients restricted to a parity class give the stencil for one type of refined vertex.
// Target: analysis.bigb