gudhi is failing test_ripser_interfaces during autopkgtest (debci)
tests on ppc64el:

 98s =================================== FAILURES ===================================
 98s ____________________________ test_ripser_interfaces ____________________________
 98s
 98s     def test_ripser_interfaces():
 98s >       cmp_rips(points.sphere(n_samples=random.randint(100, 150), ambient_dim=2))
 98s
 98s test/test_sklearn_rips_persistence.py:163:
 98s _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
 98s
 98s point_cloud = array([[-0.21236015,  0.97719147],
 98s        [ 0.9453926 ,  0.32593379],
 98s        [-0.93585084, -0.35239638],
 98s        [-0.91...-0.97009724],
 98s        [ 0.43737629,  0.89927859],
 98s        [ 0.99975938, -0.02193595],
 98s        [-0.57846424, -0.81570774]])
 98s
 98s     def cmp_rips(point_cloud):
 98s         primes = [2, 3, 11, 17, 29]  # Small list so 2 is often selected
 98s         field = random.choice(primes)
 98s         print(f"random prime = {field}")
 98s
 98s         print(f"nb points = {len(point_cloud)}, dim = {point_cloud.shape[1]}")
 98s         dists = cdist(point_cloud, point_cloud)
 98s
 98s         # Check cone radius
 98s         cr = dists.max(-1).min()
 98s         assert cr == _lower_cone_radius(dists)
 98s         assert cr < 2.0
 98s
 98s         ## Compute with the SimplexTree
 98s         stree = RipsComplex(distance_matrix=dists).create_simplex_tree(max_dimension=2)
 98s         stree.compute_persistence(homology_coeff_field=field, persistence_dim_max=True)
 98s         dgm0 = stree.persistence_intervals_in_dimension(0)
 98s         dgm1 = stree.persistence_intervals_in_dimension(1)
 98s
 98s         # Compute with Ripser
 98s         dgm = _full(dists, max_dimension=1, max_edge_length=float("inf"), homology_coeff_field=field)
 98s         # The order of the intervals may differ, so we cannot compare the arrays with np.testing.assert_almost_equal
 98s         assert bottleneck_distance(dgm0, dgm[0]) < 1e-8
 98s >       assert bottleneck_distance(dgm1, dgm[1]) < 1e-8
 98s E       assert 0.3300548399501084 < 1e-08
 98s E        +  where 0.3300548399501084 = bottleneck_distance(array([[0.23748386, 1.73508822]]), array([[0.23748386, 1.40503338]]))
 98s
 98s test/test_sklearn_rips_persistence.py:120: AssertionError


The test failure interferes with migration to testing of dependencies, like scipy

test_ripser_interfaces passed eventually in testing, so scipy was able
to migrate. However, the test is still failing in unstable.

Hence reducing severity to important, but the situation should be kept
under review.