test_basics.py

import unittest
from collections import defaultdict as ddict

import backend as F

import dgl
import networkx as nx
import numpy as np
import scipy.sparse as ssp
from dgl import DGLGraph
from utils import parametrize_idtype

D = 5
reduce_msg_shapes = set()


def message_func(edges):
    assert F.ndim(edges.src["h"]) == 2
    assert F.shape(edges.src["h"])[1] == D
    return {"m": edges.src["h"]}


def reduce_func(nodes):
    msgs = nodes.mailbox["m"]
    reduce_msg_shapes.add(tuple(msgs.shape))
    assert F.ndim(msgs) == 3
    assert F.shape(msgs)[2] == D
    return {"accum": F.sum(msgs, 1)}


def apply_node_func(nodes):
    return {"h": nodes.data["h"] + nodes.data["accum"]}


def generate_graph_old(grad=False):
    g = DGLGraph()
    g.add_nodes(10)  # 10 nodes
    # create a graph where 0 is the source and 9 is the sink
    # 17 edges
    for i in range(1, 9):
        g.add_edges(0, i)
        g.add_edges(i, 9)
    # add a back flow from 9 to 0
    g.add_edges(9, 0)
    g = g.to(F.ctx())
    ncol = F.randn((10, D))
    ecol = F.randn((17, D))
    if grad:
        ncol = F.attach_grad(ncol)
        ecol = F.attach_grad(ecol)

    g.ndata["h"] = ncol
    g.edata["w"] = ecol
    g.set_n_initializer(dgl.init.zero_initializer)
    g.set_e_initializer(dgl.init.zero_initializer)
    return g


def generate_graph(idtype, grad=False):
    """
    s, d, eid
    0, 1, 0
    1, 9, 1
    0, 2, 2
    2, 9, 3
    0, 3, 4
    3, 9, 5
    0, 4, 6
    4, 9, 7
    0, 5, 8
    5, 9, 9
    0, 6, 10
    6, 9, 11
    0, 7, 12
    7, 9, 13
    0, 8, 14
    8, 9, 15
    9, 0, 16
    """
    u = F.tensor([0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7, 0, 8, 9])
    v = F.tensor([1, 9, 2, 9, 3, 9, 4, 9, 5, 9, 6, 9, 7, 9, 8, 9, 0])
    g = dgl.graph((u, v), idtype=idtype)
    assert g.device == F.ctx()
    ncol = F.randn((10, D))
    ecol = F.randn((17, D))
    if grad:
        ncol = F.attach_grad(ncol)
        ecol = F.attach_grad(ecol)

    g.ndata["h"] = ncol
    g.edata["w"] = ecol
    g.set_n_initializer(dgl.init.zero_initializer)
    g.set_e_initializer(dgl.init.zero_initializer)
    return g


def test_compatible():
    g = generate_graph_old()


@parametrize_idtype
def test_batch_setter_getter(idtype):
    def _pfc(x):
        return list(F.zerocopy_to_numpy(x)[:, 0])

    g = generate_graph(idtype)
    # set all nodes
    g.ndata["h"] = F.zeros((10, D))
    assert F.allclose(g.ndata["h"], F.zeros((10, D)))
    # pop nodes
    old_len = len(g.ndata)
    g.ndata.pop("h")
    assert len(g.ndata) == old_len - 1
    g.ndata["h"] = F.zeros((10, D))
    # set partial nodes
    u = F.tensor([1, 3, 5], g.idtype)
    g.nodes[u].data["h"] = F.ones((3, D))
    assert _pfc(g.ndata["h"]) == [
        0.0,
        1.0,
        0.0,
        1.0,
        0.0,
        1.0,
        0.0,
        0.0,
        0.0,
        0.0,
    ]
    # get partial nodes
    u = F.tensor([1, 2, 3], g.idtype)
    assert _pfc(g.nodes[u].data["h"]) == [1.0, 0.0, 1.0]

    """
    s, d, eid
    0, 1, 0
    1, 9, 1
    0, 2, 2
    2, 9, 3
    0, 3, 4
    3, 9, 5
    0, 4, 6
    4, 9, 7
    0, 5, 8
    5, 9, 9
    0, 6, 10
    6, 9, 11
    0, 7, 12
    7, 9, 13
    0, 8, 14
    8, 9, 15
    9, 0, 16
    """
    # set all edges
    g.edata["l"] = F.zeros((17, D))
    assert _pfc(g.edata["l"]) == [0.0] * 17
    # pop edges
    old_len = len(g.edata)
    g.edata.pop("l")
    assert len(g.edata) == old_len - 1
    g.edata["l"] = F.zeros((17, D))
    # set partial edges (many-many)
    u = F.tensor([0, 0, 2, 5, 9], g.idtype)
    v = F.tensor([1, 3, 9, 9, 0], g.idtype)
    g.edges[u, v].data["l"] = F.ones((5, D))
    truth = [0.0] * 17
    truth[0] = truth[4] = truth[3] = truth[9] = truth[16] = 1.0
    assert _pfc(g.edata["l"]) == truth
    u = F.tensor([3, 4, 6], g.idtype)
    v = F.tensor([9, 9, 9], g.idtype)
    g.edges[u, v].data["l"] = F.ones((3, D))
    truth[5] = truth[7] = truth[11] = 1.0
    assert _pfc(g.edata["l"]) == truth
    u = F.tensor([0, 0, 0], g.idtype)
    v = F.tensor([4, 5, 6], g.idtype)
    g.edges[u, v].data["l"] = F.ones((3, D))
    truth[6] = truth[8] = truth[10] = 1.0
    assert _pfc(g.edata["l"]) == truth
    u = F.tensor([0, 6, 0], g.idtype)
    v = F.tensor([6, 9, 7], g.idtype)
    assert _pfc(g.edges[u, v].data["l"]) == [1.0, 1.0, 0.0]


@parametrize_idtype
def test_batch_setter_autograd(idtype):
    g = generate_graph(idtype, grad=True)
    h1 = g.ndata["h"]
    # partial set
    v = F.tensor([1, 2, 8], g.idtype)
    hh = F.attach_grad(F.zeros((len(v), D)))
    with F.record_grad():
        g.nodes[v].data["h"] = hh
        h2 = g.ndata["h"]
        F.backward(h2, F.ones((10, D)) * 2)
    assert F.array_equal(
        F.grad(h1)[:, 0],
        F.tensor([2.0, 0.0, 0.0, 2.0, 2.0, 2.0, 2.0, 2.0, 0.0, 2.0]),
    )
    assert F.array_equal(F.grad(hh)[:, 0], F.tensor([2.0, 2.0, 2.0]))


def _test_nx_conversion():
    # check conversion between networkx and DGLGraph

    def _check_nx_feature(nxg, nf, ef):
        # check node and edge feature of nxg
        # this is used to check to_networkx
        num_nodes = len(nxg)
        num_edges = nxg.size()
        if num_nodes > 0:
            node_feat = ddict(list)
            for nid, attr in nxg.nodes(data=True):
                assert len(attr) == len(nf)
                for k in nxg.nodes[nid]:
                    node_feat[k].append(F.unsqueeze(attr[k], 0))
            for k in node_feat:
                feat = F.cat(node_feat[k], 0)
                assert F.allclose(feat, nf[k])
        else:
            assert len(nf) == 0
        if num_edges > 0:
            edge_feat = ddict(lambda: [0] * num_edges)
            for u, v, attr in nxg.edges(data=True):
                assert len(attr) == len(ef) + 1  # extra id
                eid = attr["id"]
                for k in ef:
                    edge_feat[k][eid] = F.unsqueeze(attr[k], 0)
            for k in edge_feat:
                feat = F.cat(edge_feat[k], 0)
                assert F.allclose(feat, ef[k])
        else:
            assert len(ef) == 0

    n1 = F.randn((5, 3))
    n2 = F.randn((5, 10))
    n3 = F.randn((5, 4))
    e1 = F.randn((4, 5))
    e2 = F.randn((4, 7))
    g = dgl.graph(([0, 1, 3, 4], [2, 4, 0, 3]))
    g.ndata.update({"n1": n1, "n2": n2, "n3": n3})
    g.edata.update({"e1": e1, "e2": e2})

    # convert to networkx
    nxg = g.to_networkx(node_attrs=["n1", "n3"], edge_attrs=["e1", "e2"])
    assert len(nxg) == 5
    assert nxg.size() == 4
    _check_nx_feature(nxg, {"n1": n1, "n3": n3}, {"e1": e1, "e2": e2})

    # convert to DGLGraph, nx graph has id in edge feature
    # use id feature to test non-tensor copy
    g = dgl.from_networkx(nxg, node_attrs=["n1"], edge_attrs=["e1", "id"])
    # check graph size
    assert g.num_nodes() == 5
    assert g.num_edges() == 4
    # check number of features
    # test with existing dglgraph (so existing features should be cleared)
    assert len(g.ndata) == 1
    assert len(g.edata) == 2
    # check feature values
    assert F.allclose(g.ndata["n1"], n1)
    # with id in nx edge feature, e1 should follow original order
    assert F.allclose(g.edata["e1"], e1)
    assert F.array_equal(
        F.astype(g.edata["id"], F.int64), F.copy_to(F.arange(0, 4), F.cpu())
    )

    # test conversion after modifying DGLGraph
    g.edata.pop("id")  # pop id so we don't need to provide id when adding edges
    new_n = F.randn((2, 3))
    new_e = F.randn((3, 5))
    g.add_nodes(2, data={"n1": new_n})
    # add three edges, one is a multi-edge
    g.add_edges([3, 6, 0], [4, 5, 2], data={"e1": new_e})
    n1 = F.cat((n1, new_n), 0)
    e1 = F.cat((e1, new_e), 0)
    # convert to networkx again
    nxg = g.to_networkx(node_attrs=["n1"], edge_attrs=["e1"])
    assert len(nxg) == 7
    assert nxg.size() == 7
    _check_nx_feature(nxg, {"n1": n1}, {"e1": e1})

    # now test convert from networkx without id in edge feature
    # first pop id in edge feature
    for _, _, attr in nxg.edges(data=True):
        attr.pop("id")
    # test with a new graph
    g = dgl.from_networkx(nxg, node_attrs=["n1"], edge_attrs=["e1"])
    # check graph size
    assert g.num_nodes() == 7
    assert g.num_edges() == 7
    # check number of features
    assert len(g.ndata) == 1
    assert len(g.edata) == 1
    # check feature values
    assert F.allclose(g.ndata["n1"], n1)
    # edge feature order follows nxg.edges()
    edge_feat = []
    for _, _, attr in nxg.edges(data=True):
        edge_feat.append(F.unsqueeze(attr["e1"], 0))
    edge_feat = F.cat(edge_feat, 0)
    assert F.allclose(g.edata["e1"], edge_feat)

    # Test converting from a networkx graph whose nodes are
    # not labeled with consecutive-integers.
    nxg = nx.cycle_graph(5)
    nxg.remove_nodes_from([0, 4])
    for u in nxg.nodes():
        nxg.nodes[u]["h"] = F.tensor([u])
    for u, v, d in nxg.edges(data=True):
        d["h"] = F.tensor([u, v])

    g = dgl.from_networkx(nxg, node_attrs=["h"], edge_attrs=["h"])
    assert g.num_nodes() == 3
    assert g.num_edges() == 4
    assert g.has_edge_between(0, 1)
    assert g.has_edge_between(1, 2)
    assert F.allclose(g.ndata["h"], F.tensor([[1.0], [2.0], [3.0]]))
    assert F.allclose(
        g.edata["h"], F.tensor([[1.0, 2.0], [1.0, 2.0], [2.0, 3.0], [2.0, 3.0]])
    )


@parametrize_idtype
def test_apply_nodes(idtype):
    def _upd(nodes):
        return {"h": nodes.data["h"] * 2}

    g = generate_graph(idtype)
    old = g.ndata["h"]
    g.apply_nodes(_upd)
    assert F.allclose(old * 2, g.ndata["h"])
    u = F.tensor([0, 3, 4, 6], g.idtype)
    g.apply_nodes(lambda nodes: {"h": nodes.data["h"] * 0.0}, u)
    assert F.allclose(F.gather_row(g.ndata["h"], u), F.zeros((4, D)))


@parametrize_idtype
def test_apply_edges(idtype):
    def _upd(edges):
        return {"w": edges.data["w"] * 2}

    g = generate_graph(idtype)
    old = g.edata["w"]
    g.apply_edges(_upd)
    assert F.allclose(old * 2, g.edata["w"])
    u = F.tensor([0, 0, 0, 4, 5, 6], g.idtype)
    v = F.tensor([1, 2, 3, 9, 9, 9], g.idtype)
    g.apply_edges(lambda edges: {"w": edges.data["w"] * 0.0}, (u, v))
    eid = F.tensor(g.edge_ids(u, v))
    assert F.allclose(F.gather_row(g.edata["w"], eid), F.zeros((6, D)))


@parametrize_idtype
def test_update_routines(idtype):
    g = generate_graph(idtype)

    # send_and_recv
    reduce_msg_shapes.clear()
    u = [0, 0, 0, 4, 5, 6]
    v = [1, 2, 3, 9, 9, 9]
    g.send_and_recv((u, v), message_func, reduce_func, apply_node_func)
    assert reduce_msg_shapes == {(1, 3, D), (3, 1, D)}
    reduce_msg_shapes.clear()
    try:
        g.send_and_recv([u, v])
        assert False
    except:
        pass

    # pull
    v = F.tensor([1, 2, 3, 9], g.idtype)
    reduce_msg_shapes.clear()
    g.pull(v, message_func, reduce_func, apply_node_func)
    assert reduce_msg_shapes == {(1, 8, D), (3, 1, D)}
    reduce_msg_shapes.clear()

    # push
    v = F.tensor([0, 1, 2, 3], g.idtype)
    reduce_msg_shapes.clear()
    g.push(v, message_func, reduce_func, apply_node_func)
    assert reduce_msg_shapes == {(1, 3, D), (8, 1, D)}
    reduce_msg_shapes.clear()

    # update_all
    reduce_msg_shapes.clear()
    g.update_all(message_func, reduce_func, apply_node_func)
    assert reduce_msg_shapes == {(1, 8, D), (9, 1, D)}
    reduce_msg_shapes.clear()


@parametrize_idtype
def test_update_all_0deg(idtype):
    # test#1
    g = dgl.graph(([1, 2, 3, 4], [0, 0, 0, 0]), idtype=idtype, device=F.ctx())

    def _message(edges):
        return {"m": edges.src["h"]}

    def _reduce(nodes):
        return {"x": nodes.data["h"] + F.sum(nodes.mailbox["m"], 1)}

    def _apply(nodes):
        return {"x": nodes.data["x"] * 2}

    def _init2(shape, dtype, ctx, ids):
        return 2 + F.zeros(shape, dtype, ctx)

    g.set_n_initializer(_init2, "x")
    old_repr = F.randn((5, 5))
    g.ndata["h"] = old_repr
    g.update_all(_message, _reduce, _apply)
    new_repr = g.ndata["x"]
    # the first row of the new_repr should be the sum of all the node
    # features; while the 0-deg nodes should be initialized by the
    # initializer and applied with UDF.
    assert F.allclose(new_repr[1:], 2 * (2 + F.zeros((4, 5))))
    assert F.allclose(new_repr[0], 2 * F.sum(old_repr, 0))

    # test#2: graph with no edge
    g = dgl.graph(([], []), num_nodes=5, idtype=idtype, device=F.ctx())
    g.ndata["h"] = old_repr
    g.update_all(_message, _reduce, lambda nodes: {"h": nodes.data["h"] * 2})
    new_repr = g.ndata["h"]
    # should fallback to apply
    assert F.allclose(new_repr, 2 * old_repr)


@parametrize_idtype
def test_pull_0deg(idtype):
    g = dgl.graph(([0], [1]), idtype=idtype, device=F.ctx())

    def _message(edges):
        return {"m": edges.src["h"]}

    def _reduce(nodes):
        return {"x": nodes.data["h"] + F.sum(nodes.mailbox["m"], 1)}

    def _apply(nodes):
        return {"x": nodes.data["x"] * 2}

    def _init2(shape, dtype, ctx, ids):
        return 2 + F.zeros(shape, dtype, ctx)

    g.set_n_initializer(_init2, "x")
    # test#1: pull both 0deg and non-0deg nodes
    old = F.randn((2, 5))
    g.ndata["h"] = old
    g.pull([0, 1], _message, _reduce, _apply)
    new = g.ndata["x"]
    # 0deg check: initialized with the func and got applied
    assert F.allclose(new[0], F.full_1d(5, 4, dtype=F.float32))
    # non-0deg check
    assert F.allclose(new[1], F.sum(old, 0) * 2)

    # test#2: pull only 0deg node
    old = F.randn((2, 5))
    g.ndata["h"] = old
    g.pull(0, _message, _reduce, lambda nodes: {"h": nodes.data["h"] * 2})
    new = g.ndata["h"]
    # 0deg check: fallback to apply
    assert F.allclose(new[0], 2 * old[0])
    # non-0deg check: not touched
    assert F.allclose(new[1], old[1])


def test_dynamic_addition():
    N = 3
    D = 1

    g = DGLGraph()
    g = g.to(F.ctx())

    # Test node addition
    g.add_nodes(N)
    g.ndata.update({"h1": F.randn((N, D)), "h2": F.randn((N, D))})
    g.add_nodes(3)
    assert g.ndata["h1"].shape[0] == g.ndata["h2"].shape[0] == N + 3

    # Test edge addition
    g.add_edges(0, 1)
    g.add_edges(1, 0)
    g.edata.update({"h1": F.randn((2, D)), "h2": F.randn((2, D))})
    assert g.edata["h1"].shape[0] == g.edata["h2"].shape[0] == 2

    g.add_edges([0, 2], [2, 0])
    g.edata["h1"] = F.randn((4, D))
    assert g.edata["h1"].shape[0] == g.edata["h2"].shape[0] == 4

    g.add_edges(1, 2)
    g.edges[4].data["h1"] = F.randn((1, D))
    assert g.edata["h1"].shape[0] == g.edata["h2"].shape[0] == 5

    # test add edge with part of the features
    g.add_edges(2, 1, {"h1": F.randn((1, D))})
    assert len(g.edata["h1"]) == len(g.edata["h2"])


@parametrize_idtype
def test_repr(idtype):
    g = dgl.graph(
        ([0, 0, 1], [1, 2, 2]), num_nodes=10, idtype=idtype, device=F.ctx()
    )
    repr_string = g.__repr__()
    print(repr_string)
    g.ndata["x"] = F.zeros((10, 5))
    g.edata["y"] = F.zeros((3, 4))
    repr_string = g.__repr__()
    print(repr_string)


@parametrize_idtype
def test_local_var(idtype):
    g = dgl.graph(([0, 1, 2, 3], [1, 2, 3, 4]), idtype=idtype, device=F.ctx())
    g.ndata["h"] = F.zeros((g.num_nodes(), 3))
    g.edata["w"] = F.zeros((g.num_edges(), 4))

    # test override
    def foo(g):
        g = g.local_var()
        g.ndata["h"] = F.ones((g.num_nodes(), 3))
        g.edata["w"] = F.ones((g.num_edges(), 4))

    foo(g)
    assert F.allclose(g.ndata["h"], F.zeros((g.num_nodes(), 3)))
    assert F.allclose(g.edata["w"], F.zeros((g.num_edges(), 4)))

    # test out-place update
    def foo(g):
        g = g.local_var()
        g.nodes[[2, 3]].data["h"] = F.ones((2, 3))
        g.edges[[2, 3]].data["w"] = F.ones((2, 4))

    foo(g)
    assert F.allclose(g.ndata["h"], F.zeros((g.num_nodes(), 3)))
    assert F.allclose(g.edata["w"], F.zeros((g.num_edges(), 4)))

    # test out-place update 2
    def foo(g):
        g = g.local_var()
        g.apply_nodes(lambda nodes: {"h": nodes.data["h"] + 10}, [2, 3])
        g.apply_edges(lambda edges: {"w": edges.data["w"] + 10}, [2, 3])

    foo(g)
    assert F.allclose(g.ndata["h"], F.zeros((g.num_nodes(), 3)))
    assert F.allclose(g.edata["w"], F.zeros((g.num_edges(), 4)))

    # test auto-pop
    def foo(g):
        g = g.local_var()
        g.ndata["hh"] = F.ones((g.num_nodes(), 3))
        g.edata["ww"] = F.ones((g.num_edges(), 4))

    foo(g)
    assert "hh" not in g.ndata
    assert "ww" not in g.edata

    # test initializer1
    g = dgl.graph(([0, 1], [1, 1]), idtype=idtype, device=F.ctx())
    g.set_n_initializer(dgl.init.zero_initializer)

    def foo(g):
        g = g.local_var()
        g.nodes[0].data["h"] = F.ones((1, 1))
        assert F.allclose(g.ndata["h"], F.tensor([[1.0], [0.0]]))

    foo(g)

    # test initializer2
    def foo_e_initializer(shape, dtype, ctx, id_range):
        return F.ones(shape)

    g.set_e_initializer(foo_e_initializer, field="h")

    def foo(g):
        g = g.local_var()
        g.edges[0, 1].data["h"] = F.ones((1, 1))
        assert F.allclose(g.edata["h"], F.ones((2, 1)))
        g.edges[0, 1].data["w"] = F.ones((1, 1))
        assert F.allclose(g.edata["w"], F.tensor([[1.0], [0.0]]))

    foo(g)


@parametrize_idtype
def test_local_scope(idtype):
    g = dgl.graph(([0, 1, 2, 3], [1, 2, 3, 4]), idtype=idtype, device=F.ctx())
    g.ndata["h"] = F.zeros((g.num_nodes(), 3))
    g.edata["w"] = F.zeros((g.num_edges(), 4))

    # test override
    def foo(g):
        with g.local_scope():
            g.ndata["h"] = F.ones((g.num_nodes(), 3))
            g.edata["w"] = F.ones((g.num_edges(), 4))

    foo(g)
    assert F.allclose(g.ndata["h"], F.zeros((g.num_nodes(), 3)))
    assert F.allclose(g.edata["w"], F.zeros((g.num_edges(), 4)))

    # test out-place update
    def foo(g):
        with g.local_scope():
            g.nodes[[2, 3]].data["h"] = F.ones((2, 3))
            g.edges[[2, 3]].data["w"] = F.ones((2, 4))

    foo(g)
    assert F.allclose(g.ndata["h"], F.zeros((g.num_nodes(), 3)))
    assert F.allclose(g.edata["w"], F.zeros((g.num_edges(), 4)))

    # test out-place update 2
    def foo(g):
        with g.local_scope():
            g.apply_nodes(lambda nodes: {"h": nodes.data["h"] + 10}, [2, 3])
            g.apply_edges(lambda edges: {"w": edges.data["w"] + 10}, [2, 3])

    foo(g)
    assert F.allclose(g.ndata["h"], F.zeros((g.num_nodes(), 3)))
    assert F.allclose(g.edata["w"], F.zeros((g.num_edges(), 4)))

    # test auto-pop
    def foo(g):
        with g.local_scope():
            g.ndata["hh"] = F.ones((g.num_nodes(), 3))
            g.edata["ww"] = F.ones((g.num_edges(), 4))

    foo(g)
    assert "hh" not in g.ndata
    assert "ww" not in g.edata

    # test nested scope
    def foo(g):
        with g.local_scope():
            g.ndata["hh"] = F.ones((g.num_nodes(), 3))
            g.edata["ww"] = F.ones((g.num_edges(), 4))
            with g.local_scope():
                g.ndata["hhh"] = F.ones((g.num_nodes(), 3))
                g.edata["www"] = F.ones((g.num_edges(), 4))
            assert "hhh" not in g.ndata
            assert "www" not in g.edata

    foo(g)
    assert "hh" not in g.ndata
    assert "ww" not in g.edata

    # test initializer1
    g = dgl.graph(([0, 1], [1, 1]), idtype=idtype, device=F.ctx())
    g.set_n_initializer(dgl.init.zero_initializer)

    def foo(g):
        with g.local_scope():
            g.nodes[0].data["h"] = F.ones((1, 1))
            assert F.allclose(g.ndata["h"], F.tensor([[1.0], [0.0]]))

    foo(g)

    # test initializer2
    def foo_e_initializer(shape, dtype, ctx, id_range):
        return F.ones(shape)

    g.set_e_initializer(foo_e_initializer, field="h")

    def foo(g):
        with g.local_scope():
            g.edges[0, 1].data["h"] = F.ones((1, 1))
            assert F.allclose(g.edata["h"], F.ones((2, 1)))
            g.edges[0, 1].data["w"] = F.ones((1, 1))
            assert F.allclose(g.edata["w"], F.tensor([[1.0], [0.0]]))

    foo(g)


@parametrize_idtype
def test_isolated_nodes(idtype):
    g = dgl.graph(([0, 1], [1, 2]), num_nodes=5, idtype=idtype, device=F.ctx())
    assert g.num_nodes() == 5

    g = dgl.heterograph(
        {("user", "plays", "game"): ([0, 0, 1], [2, 3, 2])},
        {"user": 5, "game": 7},
        idtype=idtype,
        device=F.ctx(),
    )
    assert g.idtype == idtype
    assert g.num_nodes("user") == 5
    assert g.num_nodes("game") == 7

    # Test backward compatibility
    g = dgl.heterograph(
        {("user", "plays", "game"): ([0, 0, 1], [2, 3, 2])},
        {"user": 5, "game": 7},
        idtype=idtype,
        device=F.ctx(),
    )
    assert g.idtype == idtype
    assert g.num_nodes("user") == 5
    assert g.num_nodes("game") == 7


@parametrize_idtype
def test_send_multigraph(idtype):
    g = dgl.graph(([0, 0, 0, 2], [1, 1, 1, 1]), idtype=idtype, device=F.ctx())

    def _message_a(edges):
        return {"a": edges.data["a"]}

    def _message_b(edges):
        return {"a": edges.data["a"] * 3}

    def _reduce(nodes):
        return {"a": F.max(nodes.mailbox["a"], 1)}

    def answer(*args):
        return F.max(F.stack(args, 0), 0)

    assert g.is_multigraph

    # send by eid
    old_repr = F.randn((4, 5))
    # send_and_recv_on
    g.ndata["a"] = F.zeros((3, 5))
    g.edata["a"] = old_repr
    g.send_and_recv([0, 2, 3], message_func=_message_a, reduce_func=_reduce)
    new_repr = g.ndata["a"]
    assert F.allclose(
        new_repr[1], answer(old_repr[0], old_repr[2], old_repr[3])
    )
    assert F.allclose(new_repr[[0, 2]], F.zeros((2, 5)))


@parametrize_idtype
def test_issue_1088(idtype):
    # This test ensures that message passing on a heterograph with one edge type
    # would not crash (GitHub issue #1088).
    import dgl.function as fn

    g = dgl.heterograph(
        {("U", "E", "V"): ([0, 1, 2], [1, 2, 3])}, idtype=idtype, device=F.ctx()
    )
    g.nodes["U"].data["x"] = F.randn((3, 3))
    g.update_all(fn.copy_u("x", "m"), fn.sum("m", "y"))


@parametrize_idtype
def test_degree_bucket_edge_ordering(idtype):
    import dgl.function as fn

    g = dgl.graph(
        ([1, 3, 5, 0, 4, 2, 3, 3, 4, 5], [1, 1, 0, 0, 1, 2, 2, 0, 3, 3]),
        idtype=idtype,
        device=F.ctx(),
    )
    g.edata["eid"] = F.copy_to(F.arange(0, 10), F.ctx())

    def reducer(nodes):
        eid = F.asnumpy(F.copy_to(nodes.mailbox["eid"], F.cpu()))
        assert np.array_equal(eid, np.sort(eid, 1))
        return {"n": F.sum(nodes.mailbox["eid"], 1)}

    g.update_all(fn.copy_e("eid", "eid"), reducer)


@parametrize_idtype
def test_issue_2484(idtype):
    import dgl.function as fn

    g = dgl.graph(([0, 1, 2], [1, 2, 3]), idtype=idtype, device=F.ctx())
    x = F.copy_to(F.randn((4,)), F.ctx())
    g.ndata["x"] = x
    g.pull([2, 1], fn.u_add_v("x", "x", "m"), fn.sum("m", "x"))
    y1 = g.ndata["x"]

    g.ndata["x"] = x
    g.pull([1, 2], fn.u_add_v("x", "x", "m"), fn.sum("m", "x"))
    y2 = g.ndata["x"]

    assert F.allclose(y1, y2)