# initialize beta and beta/alpha_s schedule
beta = directives.BetaEstimate_ByEig(beta0_ratio=1e-4)
betaIt = directives.PGI_BetaAlphaSchedule(
verbose=True,
coolingFactor=2.0,
tolerance=0.2,
progress=0.2,
)
# geophy. and petro. target misfits
targets = directives.MultiTargetMisfits(
verbose=True,
chiSmall=0.5, # ask for twice as much clustering (target value is /2)
)
# add learned mref in smooth once stable
MrefInSmooth = directives.PGI_AddMrefInSmooth(
wait_till_stable=True,
verbose=True,
)
# update the parameters in smallness (L2-approx of PGI)
update_smallness = directives.PGI_UpdateParameters(
update_gmm=True, # update the GMM each iteration
kappa=np.c_[ # confidences in each mean phys. prop. of each cluster
1e10 * np.ones(
2
), # fixed background at 0 density, 0 mag. susc. (high confidences of 1e10)
[
0,
1e10,
], # density-contrasting cluster: updatable density mean, fixed mag. susc.
[
1e10,
0,
invProb = inverse_problem.BaseInvProblem(dmis, reg, opt)
# directives
Alphas = directives.AlphasSmoothEstimate_ByEig(alpha0_ratio=10.0, verbose=True)
beta = directives.BetaEstimate_ByEig(beta0_ratio=1e-6)
betaIt = directives.PGI_BetaAlphaSchedule(
verbose=True,
coolingFactor=2.0,
warmingFactor=1.0,
tolerance=0.1,
update_rate=1,
progress=0.2,
)
targets = directives.MultiTargetMisfits(verbose=True)
petrodir = directives.PGI_UpdateParameters()
addmref = directives.PGI_AddMrefInSmooth(verbose=True)
# Setup Inversion
inv = inversion.BaseInversion(
invProb, directiveList=[Alphas, beta, petrodir, targets, addmref, betaIt])
# Initial model same as for Tikhonov
mcluster = inv.run(m0)
# Final Plot
fig, axes = plt.subplots(1, 3, figsize=(12 * 1.2, 4 * 1.2))
for i in range(prob.G.shape[0]):
axes[0].plot(prob.G[i, :])
axes[0].set_title("Columns of matrix G")
axes[1].hist(mtrue, bins=20, linewidth=3.0, density=True, color="k")