class TestFeaturizer(unittest.TestCase):
def setUp(self):
self.pdbfile = pdbfile
self.traj = mdtraj.load(xtcfile, top=self.pdbfile)
self.feat = MDFeaturizer(self.pdbfile)
def test_select_backbone(self):
inds = self.feat.select_Backbone()
def test_select_all(self):
self.feat.add_all()
assert (self.feat.dimension() == self.traj.n_atoms * 3)
refmap = np.reshape(self.traj.xyz,
(len(self.traj), self.traj.n_atoms * 3))
assert (np.all(refmap == self.feat.map(self.traj)))
def test_select(self):
sel = np.array([1, 2, 5, 20], dtype=int)
self.feat.add_selection(sel)
assert (self.feat.dimension() == sel.shape[0] * 3)
refmap = np.reshape(self.traj.xyz[:, sel, :],
(len(self.traj), sel.shape[0] * 3))
assert (np.all(refmap == self.feat.map(self.traj)))
def test_distances(self):
sel = np.array([1, 2, 5, 20], dtype=int)
pairs_expected = np.array([[1, 5], [1, 20], [2, 5], [2, 20], [5, 20]])
pairs = self.feat.pairs(sel)
assert (pairs.shape == pairs_expected.shape)
assert (np.all(pairs == pairs_expected))
self.feat.add_distances(
pairs,
periodic=False) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs_expected.shape[0])
X = self.traj.xyz[:, pairs_expected[:, 0], :]
Y = self.traj.xyz[:, pairs_expected[:, 1], :]
D = np.sqrt(np.sum((X - Y)**2, axis=2))
assert (np.allclose(D, self.feat.map(self.traj)))
def test_inverse_distances(self):
sel = np.array([1, 2, 5, 20], dtype=int)
pairs_expected = np.array([[1, 5], [1, 20], [2, 5], [2, 20], [5, 20]])
pairs = self.feat.pairs(sel)
assert (pairs.shape == pairs_expected.shape)
assert (np.all(pairs == pairs_expected))
self.feat.add_inverse_distances(
pairs,
periodic=False) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs_expected.shape[0])
X = self.traj.xyz[:, pairs_expected[:, 0], :]
Y = self.traj.xyz[:, pairs_expected[:, 1], :]
Dinv = 1.0 / np.sqrt(np.sum((X - Y)**2, axis=2))
assert (np.allclose(Dinv, self.feat.map(self.traj)))
def test_ca_distances(self):
sel = self.feat.select_Ca()
assert (np.all(sel == range(self.traj.n_atoms))
) # should be all for this Ca-traj
pairs = self.feat.pairs(sel)
self.feat.add_distances_ca(
periodic=False) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs.shape[0])
X = self.traj.xyz[:, pairs[:, 0], :]
Y = self.traj.xyz[:, pairs[:, 1], :]
D = np.sqrt(np.sum((X - Y)**2, axis=2))
assert (np.allclose(D, self.feat.map(self.traj)))
def test_contacts(self):
sel = np.array([1, 2, 5, 20], dtype=int)
pairs_expected = np.array([[1, 5], [1, 20], [2, 5], [2, 20], [5, 20]])
pairs = self.feat.pairs(sel)
assert (pairs.shape == pairs_expected.shape)
assert (np.all(pairs == pairs_expected))
self.feat.add_contacts(
pairs, threshold=0.5,
periodic=False) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs_expected.shape[0])
X = self.traj.xyz[:, pairs_expected[:, 0], :]
Y = self.traj.xyz[:, pairs_expected[:, 1], :]
D = np.sqrt(np.sum((X - Y)**2, axis=2))
C = np.zeros(D.shape)
I = np.argwhere(D <= 0.5)
C[I[:, 0], I[:, 1]] = 1.0
assert (np.allclose(C, self.feat.map(self.traj)))
def test_angles(self):
sel = np.array([[1, 2, 5], [1, 3, 8], [2, 9, 10]], dtype=int)
self.feat.add_angles(sel)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.map(self.traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
def test_angles_deg(self):
sel = np.array([[1, 2, 5], [1, 3, 8], [2, 9, 10]], dtype=int)
self.feat.add_angles(sel, deg=True)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.map(self.traj)
assert (np.alltrue(Y >= -180.0))
assert (np.alltrue(Y <= 180.0))
def test_dihedrals(self):
sel = np.array([[1, 2, 5, 6], [1, 3, 8, 9], [2, 9, 10, 12]], dtype=int)
self.feat.add_dihedrals(sel)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.map(self.traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
def test_dihedrals_deg(self):
sel = np.array([[1, 2, 5, 6], [1, 3, 8, 9], [2, 9, 10, 12]], dtype=int)
self.feat.add_dihedrals(sel, deg=True)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.map(self.traj)
assert (np.alltrue(Y >= -180.0))
assert (np.alltrue(Y <= 180.0))
def test_backbone_dihedrals(self):
# TODO: test me
pass
def test_backbone_dihedrals_deg(self):
# TODO: test me
pass
def test_custom_feature(self):
# TODO: test me
pass
class TestFeaturizer(unittest.TestCase):
@classmethod
def setUpClass(cls):
import tempfile
cls.asn_leu_pdbfile = tempfile.mkstemp(suffix=".pdb")[1]
with open(cls.asn_leu_pdbfile, 'w') as fh:
fh.write(asn_leu_pdb)
cls.asn_leu_traj = tempfile.mktemp(suffix='.xtc')
# create traj for asn_leu
n_frames = 4001
traj = mdtraj.load(cls.asn_leu_pdbfile)
ref = traj.xyz
new_xyz = np.empty((n_frames, ref.shape[1], 3))
noise = np.random.random(new_xyz.shape)
new_xyz[:, :, :] = noise + ref
traj.xyz = new_xyz
traj.time = np.arange(n_frames)
traj.save(cls.asn_leu_traj)
super(TestFeaturizer, cls).setUpClass()
@classmethod
def tearDownClass(cls):
try:
os.unlink(cls.asn_leu_pdbfile)
except EnvironmentError:
pass
super(TestFeaturizer, cls).tearDownClass()
def setUp(self):
self.pdbfile = pdbfile
self.traj = mdtraj.load(xtcfile, top=self.pdbfile)
self.feat = MDFeaturizer(self.pdbfile)
self.atol = 1e-5
self.ref_frame = 0
self.atom_indices = np.arange(0, self.traj.n_atoms / 2)
def test_select_backbone(self):
inds = self.feat.select_Backbone()
def test_select_all(self):
self.feat.add_all()
assert (self.feat.dimension() == self.traj.n_atoms * 3)
refmap = np.reshape(self.traj.xyz,
(len(self.traj), self.traj.n_atoms * 3))
assert (np.all(refmap == self.feat.transform(self.traj)))
def test_select(self):
sel = np.array([1, 2, 5, 20], dtype=int)
self.feat.add_selection(sel)
assert (self.feat.dimension() == sel.shape[0] * 3)
refmap = np.reshape(self.traj.xyz[:, sel, :],
(len(self.traj), sel.shape[0] * 3))
assert (np.all(refmap == self.feat.transform(self.traj)))
def test_distances(self):
sel = np.array([1, 2, 5, 20], dtype=int)
pairs_expected = np.array([[1, 5], [1, 20], [2, 5], [2, 20], [5, 20]])
pairs = self.feat.pairs(sel, excluded_neighbors=2)
assert (pairs.shape == pairs_expected.shape)
assert (np.all(pairs == pairs_expected))
self.feat.add_distances(
pairs,
periodic=False) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs_expected.shape[0])
X = self.traj.xyz[:, pairs_expected[:, 0], :]
Y = self.traj.xyz[:, pairs_expected[:, 1], :]
D = np.sqrt(np.sum((X - Y)**2, axis=2))
assert (np.allclose(D, self.feat.transform(self.traj)))
def test_inverse_distances(self):
sel = np.array([1, 2, 5, 20], dtype=int)
pairs_expected = np.array([[1, 5], [1, 20], [2, 5], [2, 20], [5, 20]])
pairs = self.feat.pairs(sel, excluded_neighbors=2)
assert (pairs.shape == pairs_expected.shape)
assert (np.all(pairs == pairs_expected))
self.feat.add_inverse_distances(
pairs,
periodic=False) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs_expected.shape[0])
X = self.traj.xyz[:, pairs_expected[:, 0], :]
Y = self.traj.xyz[:, pairs_expected[:, 1], :]
Dinv = 1.0 / np.sqrt(np.sum((X - Y)**2, axis=2))
assert (np.allclose(Dinv, self.feat.transform(self.traj)))
def test_ca_distances(self):
sel = self.feat.select_Ca()
assert (np.all(sel == list(range(self.traj.n_atoms)))
) # should be all for this Ca-traj
pairs = self.feat.pairs(sel, excluded_neighbors=0)
self.feat.add_distances_ca(
periodic=False, excluded_neighbors=0
) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs.shape[0])
X = self.traj.xyz[:, pairs[:, 0], :]
Y = self.traj.xyz[:, pairs[:, 1], :]
D = np.sqrt(np.sum((X - Y)**2, axis=2))
assert (np.allclose(D, self.feat.transform(self.traj)))
def test_ca_distances_with_all_atom_geometries(self):
feat = MDFeaturizer(pdbfile_ops_aa)
feat.add_distances_ca(excluded_neighbors=0)
D_aa = feat.transform(mdtraj.load(pdbfile_ops_aa))
# Create a reference
feat_just_ca = MDFeaturizer(pdbfile_ops_Ca)
feat_just_ca.add_distances(np.arange(feat_just_ca.topology.n_atoms))
D_ca = feat_just_ca.transform(mdtraj.load(pdbfile_ops_Ca))
assert (np.allclose(D_aa, D_ca))
def test_ca_distances_with_all_atom_geometries_and_exclusions(self):
feat = MDFeaturizer(pdbfile_ops_aa)
feat.add_distances_ca(excluded_neighbors=2)
D_aa = feat.transform(mdtraj.load(pdbfile_ops_aa))
# Create a reference
feat_just_ca = MDFeaturizer(pdbfile_ops_Ca)
ca_pairs = feat.pairs(feat_just_ca.select_Ca(), excluded_neighbors=2)
feat_just_ca.add_distances(ca_pairs)
D_ca = feat_just_ca.transform(mdtraj.load(pdbfile_ops_Ca))
assert (np.allclose(D_aa, D_ca))
def test_contacts(self):
sel = np.array([1, 2, 5, 20], dtype=int)
pairs_expected = np.array([[1, 5], [1, 20], [2, 5], [2, 20], [5, 20]])
pairs = self.feat.pairs(sel, excluded_neighbors=2)
assert (pairs.shape == pairs_expected.shape)
assert (np.all(pairs == pairs_expected))
self.feat.add_contacts(
pairs, threshold=0.5,
periodic=False) # unperiodic distances such that we can compare
assert (self.feat.dimension() == pairs_expected.shape[0])
X = self.traj.xyz[:, pairs_expected[:, 0], :]
Y = self.traj.xyz[:, pairs_expected[:, 1], :]
D = np.sqrt(np.sum((X - Y)**2, axis=2))
C = np.zeros(D.shape)
I = np.argwhere(D <= 0.5)
C[I[:, 0], I[:, 1]] = 1.0
assert (np.allclose(C, self.feat.transform(self.traj)))
def test_contacts_count_contacts(self):
sel = np.array([1, 2, 5, 20], dtype=int)
pairs_expected = np.array([[1, 5], [1, 20], [2, 5], [2, 20], [5, 20]])
pairs = self.feat.pairs(sel, excluded_neighbors=2)
assert (pairs.shape == pairs_expected.shape)
assert (np.all(pairs == pairs_expected))
self.feat.add_contacts(
pairs, threshold=0.5, periodic=False, count_contacts=True
) # unperiodic distances such that we can compare
# The dimensionality of the feature is now one
assert (self.feat.dimension() == 1)
X = self.traj.xyz[:, pairs_expected[:, 0], :]
Y = self.traj.xyz[:, pairs_expected[:, 1], :]
D = np.sqrt(np.sum((X - Y)**2, axis=2))
C = np.zeros(D.shape)
I = np.argwhere(D <= 0.5)
C[I[:, 0], I[:, 1]] = 1.0
# Count the contacts
C = C.sum(1, keepdims=True)
assert (np.allclose(C, self.feat.transform(self.traj)))
def test_angles(self):
sel = np.array([[1, 2, 5], [1, 3, 8], [2, 9, 10]], dtype=int)
self.feat.add_angles(sel)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.transform(self.traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
self.assertEqual(len(self.feat.describe()), self.feat.dimension())
def test_angles_deg(self):
sel = np.array([[1, 2, 5], [1, 3, 8], [2, 9, 10]], dtype=int)
self.feat.add_angles(sel, deg=True)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.transform(self.traj)
assert (np.alltrue(Y >= -180.0))
assert (np.alltrue(Y <= 180.0))
def test_angles_cossin(self):
sel = np.array([[1, 2, 5], [1, 3, 8], [2, 9, 10]], dtype=int)
self.feat.add_angles(sel, cossin=True)
assert (self.feat.dimension() == 2 * sel.shape[0])
Y = self.feat.transform(self.traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
desc = self.feat.describe()
self.assertEqual(len(desc), self.feat.dimension())
def test_dihedrals(self):
sel = np.array([[1, 2, 5, 6], [1, 3, 8, 9], [2, 9, 10, 12]], dtype=int)
self.feat.add_dihedrals(sel)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.transform(self.traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
self.assertEqual(len(self.feat.describe()), self.feat.dimension())
def test_dihedrals_deg(self):
sel = np.array([[1, 2, 5, 6], [1, 3, 8, 9], [2, 9, 10, 12]], dtype=int)
self.feat.add_dihedrals(sel, deg=True)
assert (self.feat.dimension() == sel.shape[0])
Y = self.feat.transform(self.traj)
assert (np.alltrue(Y >= -180.0))
assert (np.alltrue(Y <= 180.0))
self.assertEqual(len(self.feat.describe()), self.feat.dimension())
def test_dihedrials_cossin(self):
sel = np.array([[1, 2, 5, 6], [1, 3, 8, 9], [2, 9, 10, 12]], dtype=int)
self.feat.add_dihedrals(sel, cossin=True)
assert (self.feat.dimension() == 2 * sel.shape[0])
Y = self.feat.transform(self.traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
desc = self.feat.describe()
self.assertEqual(len(desc), self.feat.dimension())
def test_backbone_dihedrals(self):
self.feat = MDFeaturizer(topfile=self.asn_leu_pdbfile)
self.feat.add_backbone_torsions()
traj = mdtraj.load(self.asn_leu_pdbfile)
Y = self.feat.transform(traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
desc = self.feat.describe()
self.assertEqual(len(desc), self.feat.dimension())
def test_backbone_dihedrals_deg(self):
self.feat = MDFeaturizer(topfile=self.asn_leu_pdbfile)
self.feat.add_backbone_torsions(deg=True)
traj = mdtraj.load(self.asn_leu_pdbfile)
Y = self.feat.transform(traj)
assert (np.alltrue(Y >= -180.0))
assert (np.alltrue(Y <= 180.0))
desc = self.feat.describe()
self.assertEqual(len(desc), self.feat.dimension())
def test_backbone_dihedrals_cossin(self):
self.feat = MDFeaturizer(topfile=self.asn_leu_pdbfile)
self.feat.add_backbone_torsions(cossin=True)
traj = mdtraj.load(self.asn_leu_traj, top=self.asn_leu_pdbfile)
Y = self.feat.transform(traj)
self.assertEqual(Y.shape,
(len(traj), 3 * 4)) # (3 phi + 3 psi)*2 [cos, sin]
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
desc = self.feat.describe()
assert "COS" in desc[0]
assert "SIN" in desc[1]
self.assertEqual(len(desc), self.feat.dimension())
def test_backbone_dihedrials_chi(self):
self.feat = MDFeaturizer(topfile=self.asn_leu_pdbfile)
self.feat.add_chi1_torsions()
traj = mdtraj.load(self.asn_leu_pdbfile)
Y = self.feat.transform(traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
desc = self.feat.describe()
self.assertEqual(len(desc), self.feat.dimension())
def test_backbone_dihedrials_chi_cossin(self):
self.feat = MDFeaturizer(topfile=self.asn_leu_pdbfile)
self.feat.add_chi1_torsions(cossin=True)
traj = mdtraj.load(self.asn_leu_pdbfile)
Y = self.feat.transform(traj)
assert (np.alltrue(Y >= -np.pi))
assert (np.alltrue(Y <= np.pi))
desc = self.feat.describe()
assert "COS" in desc[0]
assert "SIN" in desc[1]
self.assertEqual(len(desc), self.feat.dimension())
def test_custom_feature(self):
# TODO: test me
pass
def test_MinRmsd(self):
# Test the Trajectory-input variant
self.feat.add_minrmsd_to_ref(self.traj[self.ref_frame])
# and the file-input variant
self.feat.add_minrmsd_to_ref(xtcfile, ref_frame=self.ref_frame)
test_Y = self.feat.transform(self.traj).squeeze()
# now the reference
ref_Y = mdtraj.rmsd(self.traj, self.traj[self.ref_frame])
verbose_assertion_minrmsd(ref_Y, test_Y, self)
assert self.feat.dimension() == 2
assert len(self.feat.describe()) == 2
def test_MinRmsd_with_atom_indices(self):
# Test the Trajectory-input variant
self.feat.add_minrmsd_to_ref(self.traj[self.ref_frame],
atom_indices=self.atom_indices)
# and the file-input variant
self.feat.add_minrmsd_to_ref(xtcfile,
ref_frame=self.ref_frame,
atom_indices=self.atom_indices)
test_Y = self.feat.transform(self.traj).squeeze()
# now the reference
ref_Y = mdtraj.rmsd(self.traj,
self.traj[self.ref_frame],
atom_indices=self.atom_indices)
verbose_assertion_minrmsd(ref_Y, test_Y, self)
assert self.feat.dimension() == 2
assert len(self.feat.describe()) == 2
def test_MinRmsd_with_atom_indices_precentered(self):
# Test the Trajectory-input variant
self.feat.add_minrmsd_to_ref(self.traj[self.ref_frame],
atom_indices=self.atom_indices,
precentered=True)
# and the file-input variant
self.feat.add_minrmsd_to_ref(xtcfile,
ref_frame=self.ref_frame,
atom_indices=self.atom_indices,
precentered=True)
test_Y = self.feat.transform(self.traj).squeeze()
# now the reference
ref_Y = mdtraj.rmsd(self.traj,
self.traj[self.ref_frame],
atom_indices=self.atom_indices,
precentered=True)
verbose_assertion_minrmsd(ref_Y, test_Y, self)
assert self.feat.dimension() == 2
assert len(self.feat.describe()) == 2
def test_Residue_Mindist_Ca_all(self):
n_ca = self.feat.topology.n_atoms
self.feat.add_residue_mindist(scheme='ca')
D = self.feat.transform(self.traj)
Dref = mdtraj.compute_contacts(self.traj, scheme='ca')[0]
assert np.allclose(D, Dref)
assert len(self.feat.describe()) == self.feat.dimension()
def test_Residue_Mindist_Ca_all_threshold(self):
threshold = .7
self.feat.add_residue_mindist(scheme='ca', threshold=threshold)
D = self.feat.transform(self.traj)
Dref = mdtraj.compute_contacts(self.traj, scheme='ca')[0]
Dbinary = np.zeros_like(Dref)
I = np.argwhere(Dref <= threshold)
Dbinary[I[:, 0], I[:, 1]] = 1
assert np.allclose(D, Dbinary)
assert len(self.feat.describe()) == self.feat.dimension()
def test_Residue_Mindist_Ca_array(self):
contacts = np.array([[
20,
10,
], [10, 0]])
self.feat.add_residue_mindist(scheme='ca', residue_pairs=contacts)
D = self.feat.transform(self.traj)
Dref = mdtraj.compute_contacts(self.traj,
scheme='ca',
contacts=contacts)[0]
assert np.allclose(D, Dref)
assert len(self.feat.describe()) == self.feat.dimension()
def test_Group_Mindist_One_Group(self):
group0 = [0, 20, 30, 0]
self.feat.add_group_mindist(
group_definitions=[group0]) # Even with duplicates
D = self.feat.transform(self.traj)
dist_list = list(combinations(np.unique(group0), 2))
Dref = mdtraj.compute_distances(self.traj, dist_list)
assert np.allclose(D.squeeze(), Dref.min(1))
assert len(self.feat.describe()) == self.feat.dimension()
def test_Group_Mindist_All_Three_Groups(self):
group0 = [0, 20, 30, 0]
group1 = [1, 21, 31, 1]
group2 = [2, 22, 32, 2]
self.feat.add_group_mindist(group_definitions=[group0, group1, group2])
D = self.feat.transform(self.traj)
# Now the references, computed separately for each combination of groups
dist_list_01 = np.array(
list(product(np.unique(group0), np.unique(group1))))
dist_list_02 = np.array(
list(product(np.unique(group0), np.unique(group2))))
dist_list_12 = np.array(
list(product(np.unique(group1), np.unique(group2))))
Dref_01 = mdtraj.compute_distances(self.traj, dist_list_01).min(1)
Dref_02 = mdtraj.compute_distances(self.traj, dist_list_02).min(1)
Dref_12 = mdtraj.compute_distances(self.traj, dist_list_12).min(1)
Dref = np.vstack((Dref_01, Dref_02, Dref_12)).T
assert np.allclose(D.squeeze(), Dref)
assert len(self.feat.describe()) == self.feat.dimension()
def test_Group_Mindist_All_Three_Groups_threshold(self):
threshold = .7
group0 = [0, 20, 30, 0]
group1 = [1, 21, 31, 1]
group2 = [2, 22, 32, 2]
self.feat.add_group_mindist(group_definitions=[group0, group1, group2],
threshold=threshold)
D = self.feat.transform(self.traj)
# Now the references, computed separately for each combination of groups
dist_list_01 = np.array(
list(product(np.unique(group0), np.unique(group1))))
dist_list_02 = np.array(
list(product(np.unique(group0), np.unique(group2))))
dist_list_12 = np.array(
list(product(np.unique(group1), np.unique(group2))))
Dref_01 = mdtraj.compute_distances(self.traj, dist_list_01).min(1)
Dref_02 = mdtraj.compute_distances(self.traj, dist_list_02).min(1)
Dref_12 = mdtraj.compute_distances(self.traj, dist_list_12).min(1)
Dref = np.vstack((Dref_01, Dref_02, Dref_12)).T
Dbinary = np.zeros_like(Dref)
I = np.argwhere(Dref <= threshold)
Dbinary[I[:, 0], I[:, 1]] = 1
assert np.allclose(D, Dbinary)
assert len(self.feat.describe()) == self.feat.dimension()
def test_Group_Mindist_Some_Three_Groups(self):
group0 = [0, 20, 30, 0]
group1 = [1, 21, 31, 1]
group2 = [2, 22, 32, 2]
group_pairs = np.array([[0, 1], [2, 2], [0, 2]])
self.feat.add_group_mindist(group_definitions=[group0, group1, group2],
group_pairs=group_pairs)
D = self.feat.transform(self.traj)
# Now the references, computed separately for each combination of groups
dist_list_01 = np.array(
list(product(np.unique(group0), np.unique(group1))))
dist_list_02 = np.array(
list(product(np.unique(group0), np.unique(group2))))
dist_list_22 = np.array(list(combinations(np.unique(group2), 2)))
Dref_01 = mdtraj.compute_distances(self.traj, dist_list_01).min(1)
Dref_02 = mdtraj.compute_distances(self.traj, dist_list_02).min(1)
Dref_22 = mdtraj.compute_distances(self.traj, dist_list_22).min(1)
Dref = np.vstack((Dref_01, Dref_22, Dref_02)).T
assert np.allclose(D.squeeze(), Dref)
assert len(self.feat.describe()) == self.feat.dimension()