Important differences between PyClaw and Clawpack

PyClaw incorporates some important changes relative to Clawpack. Most of these are planned for inclusion in Clawpack 5.0.

Interleaved arrays

PyClaw uses a different array indexing than Clawpack. In PetClaw, the value of the $m$th conserved quantity at $(x_i,y_j)$ is

q[m,i,j]

That is, the index $m$ comes first, whereas in Clawpack it comes last. This “interleaved” array layout is potentially more cache-efficient. The next version of Clawpack (5.0) will also use interleaved arrays.