def test_inference():
# Test inference with different weights in different directions
X, Y = toy.generate_blocks_multinomial(noise=2, n_samples=1, seed=1)
x, y = X[0], Y[0]
n_states = x.shape[-1]
edges = _make_grid_edges(x, neighborhood=4)
edge_list = _make_grid_edges(x, 4, return_lists=True)
edges = np.vstack(edge_list)
pw_horz = -1 * np.eye(n_states)
xx, yy = np.indices(pw_horz.shape)
# linear ordering constraint horizontally
pw_horz[xx > yy] = 1
# high cost for unequal labels vertically
pw_vert = -1 * np.eye(n_states)
pw_vert[xx != yy] = 1
pw_vert *= 10
# generate edge weights
edge_weights_horizontal = np.repeat(pw_horz[np.newaxis, :, :],
edge_list[0].shape[0], axis=0)
edge_weights_vertical = np.repeat(pw_vert[np.newaxis, :, :],
edge_list[1].shape[0], axis=0)
edge_weights = np.vstack([edge_weights_horizontal, edge_weights_vertical])
# do inference
res = lp_general_graph(-x.reshape(-1, n_states), edges, edge_weights,
exact=False)
# same inference through CRF inferface
crf = DirectionalGridCRF(n_states=3, inference_method='lp')
w = np.hstack([np.ones(3), -pw_horz.ravel(), -pw_vert.ravel()])
y_pred = crf.inference(x, w, relaxed=True)
assert_array_almost_equal(res[0], y_pred[0].reshape(-1, n_states))
assert_array_almost_equal(res[1], y_pred[1])
assert_array_equal(y, np.argmax(y_pred[0], axis=-1))
def test_energy():
# make sure that energy as computed by ssvm is the same as by lp
np.random.seed(0)
found_fractional = False
while not found_fractional:
x = np.random.normal(size=(2, 2, 3))
unary_params = np.ones(3)
pairwise_params = np.random.normal() * np.eye(3)
edges = _make_grid_edges(x)
# check map inference
inf_res, energy_lp = _inference_lp(
x, unary_params, pairwise_params, edges=edges, relaxed=True, return_energy=True, exact=True
)
found_fractional = np.any(np.max(inf_res[0], axis=-1) != 1)
energy_svm = compute_energy(x, inf_res, unary_params, pairwise_params, neighborhood=4)
assert_almost_equal(energy_lp, -energy_svm)
