Symbolic coefficient erroring due to factorization

[mloubout]

Symbolic coefficient cannot be applied to p.dx2 + q.dx2 because it is factorized as (p+q).dx2.

MFE:

from devito import Eq, Grid, Operator, TimeFunction, Coefficient, Substitutions
import numpy as np
from sympy import finite_diff_weights

grid = Grid(shape=(100,100,100))
p = TimeFunction(name='p', grid=grid, #save=tt.num,
                        space_order=8, time_order=2,
                        coefficients='symbolic' )  # the customized coefficients

q = TimeFunction(name='q', grid=grid, #save=tt.num,
                        space_order=8, time_order=2,
                        coefficients='symbolic' )  # the customized coefficients

OP = Operator( [ Eq(p.forward, p.dx2 + q.dx2)] )