def check_convergence(datasets, expected_rate, tol=0.2):
"""For a set of convergence test check that the rate of convergence as dt
and h -> 0 is as expected. dt and h are linked so it is enough to
test only for dt.
"""
rate = mm.convergence_rate(datasets, error_norm_norm=max)
# Check if near to expected value
ok = abs(rate - expected_rate) < tol
# Print messages, identify by first dataset for simplicity.
dataid = _default_label(datasets[0])
if ok:
mm.okprint("convergence rate", rate, "ok in", dataid)
else:
mm.badprint("convergence rate", rate,
"but expected", expected_rate, "+/-", tol,
"in", dataid)
# ??ds check goodness of fit?
return ok