Example #1
0
def independence_chain(T, T0, sigma=1.): 
    nparmas = T.param.size
    T2 = Affine(subtype=T.subtype, flag2d=T.flag2d)
    T2.param = T0.param + sigma*np.random.normal(size=nparams)
    sigma_ = np.maximum(sigma, 1e-20)
    tmp = (T2.param/sigma_)**2-(T.param/sigma_)**2
    r = np.exp(-.5*tmp.sum()) 
    return T2, r
Example #2
0
def random_walk(T, T0, sigma=1.): 
    nparams = T.param.size
    T2 = Affine(subtype=T.subtype, flag2d=T.flag2d)
    T2.param = T.param + sigma*np.random.normal(size=nparams)
    return T2, 1.