LDA implementation with pymc3

Questions
18

For ADVI I tried using :

def log_lda(theta,phi):
    def ll_lda(value):  
        dixs, vixs = value.nonzero()
        vfreqs = value[dixs, vixs]
        ll =vfreqs* pm.math.logsumexp(t.log(theta[dixs]) + t.log(phi.T[vixs]), axis = 1).ravel()
        return t.sum(ll) 
    return ll_lda

with model: 
    theta = pm.Dirichlet("thetas", a=alpha, shape=(D, K))
    phi = pm.Dirichlet("phis", a=beta, shape=(K, V))
    doc = pm.DensityDist('doc', log_lda(theta,phi), observed=doc_t)