Multiple StellarPopulation instances

Because parameter state and dirtiness is specific to each instance, but the computed model is held by the module level driver object, having multiple StellarPopulation instances can cause a model to not be recomputed even though it should be (example code below) This might also cause problems with shared memory multiprocessing.

Some documentation advising only a single sps instance per program might be a good idea.

from numpy.testing import assert_allclose
import fsps
sps = fsps.StellarPopulation(zcontinuous=1, vactoair_flag=False)
pop = fsps.StellarPopulation(zcontinuous=1, vactoair_flag=False)
w1, s1 = sps.get_spectrum(tage=10.0)
w, s = pop.get_spectrum(tage=1.0)
w2, s2 = sps.get_spectrum(tage=10.0)
assert_allclose(s, s2) # this should not pass, but does
assert_allclose(s1, s2) # this should not fail, but does

StellarPopulation.get_spectrum と、issue で説明されているモジュールレベルの driver state から始めます。2 つのインスタンスで提示されたシーケンスを再現し、その後、パラメータの dirty 状態とモデルの再計算がどのように共有されるかを追跡します。各インスタンスが自身のパラメータと整合する結果を返し、例にある 2 つの assertions も満たせば完了です。