rho = 0
for l in range(len(layers)):
m = wherePositive(z -
z_bottom) * whereNonPositive(z -
(z_bottom + layers[l]))
v_p = v_p * (1 - m) + v_Ps[l] * m
v_s = v_s * (1 - m) + v_Ss[l] * m
rho = rho * (1 - m) + rhos[l] * m
vareps = vareps * (1 - m) + epss[l] * m
gamma = gamma * (1 - m) + gammas[l] * m
delta = delta * (1 - m) + deltas[l] * m
z_bottom += layers[l]
wl = Ricker(frq)
dt = min((1. / 5.) *
min(inf(domain.getSize() / v_p), inf(domain.getSize() / v_s)),
wl.getTimeScale())
sw = HTIWave(domain,
v_p,
v_s,
wl,
src_tags[0],
source_vector=src_dir,
eps=vareps,
gamma=gamma,
delta=delta,
rho=rho,
absorption_zone=None,
absorption_cut=1e-2,
lumping=True,
