Fix drawing (#142)

This fixes #137 and #140. Among other things, user can specify
* node size, node line color, node face color, node line width, edge line width, and edge color as dictionaries, iterables, or strings.
* edge face color as a colormap, dictionary, iterable or string.

The `draw` function is now modularized into `draw_xgi_nodes`, `draw_xgi_hyperedges`, and `draw_xgi_complexes` as well as a few helper functions. In addition, nodes are now drawn with `scatter` not `Circle` objects.

tests/generators/test_classic.py

@@ -10,8 +10,12 @@ def test_empty_hypergraph():
     assert (H.num_nodes, H.num_edges) == (0, 0)
 
 
-def test_star_clique():
+def test_empty_hypergraph():
+    SC = xgi.empty_simplicial_complex()
+    assert (SC.num_nodes, SC.num_edges) == (0, 0)
 
+
+def test_star_clique():
     with pytest.raises(ValueError):
         H = xgi.star_clique(-1, 7, 3)
     with pytest.raises(ValueError):

tutorials/Tutorial 5 - Plotting.ipynb

@@ -106,13 +106,13 @@
     "cmap = plt.cm.Blues\n",
     "\n",
     "ax = plt.subplot(1,2,1)\n",
-    "xgi.draw(H, pos, cmap=cmap, ax=ax)\n",
+    "xgi.draw(H, pos, edge_fc=cmap, ax=ax)\n",
     "\n",
     "#Qualitative colormap\n",
     "cmap = plt.cm.Set1\n",
     "\n",
     "ax = plt.subplot(1,2,2)\n",
-    "xgi.draw(H, pos, cmap=cmap, ax=ax)"
+    "xgi.draw(H, pos, edge_fc=cmap, ax=ax)"
    ]
   },
   {
@@ -136,9 +136,9 @@
     "node_fc = 'black'\n",
     "node_ec = 'white'\n",
     "node_lw = 2\n",
-    "node_size = 0.07\n",
+    "node_size = 20\n",
     "\n",
-    "xgi.draw(H, pos, cmap=cmap, edge_lc=edge_lc, edge_lw=edge_lw,\n",
+    "xgi.draw(H, pos, edge_fc=cmap, edge_lc=edge_lc, edge_lw=edge_lw,\n",
     "         node_fc=node_fc, node_ec=node_ec, node_lw=node_lw, node_size=node_size)"
    ]
   },
@@ -201,7 +201,7 @@
    "metadata": {},
    "source": [
     "# Example: generative model\n",
-    "We generate and visualize a [Chung-Lu hypergraph](https://doi.org/10.1093/comnet/cnx001)."
+    "We generate and visualize a [random hypergraph](https://doi.org/10.1093/comnet/cnx001)."
    ]
   },
   {
@@ -211,10 +211,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "n = 500\n",
-    "k1 = {i : random.randint(10, 30) for i in range(n)}\n",
-    "k2 = {i : sorted(k1.values())[i] for i in range(n)}\n",
-    "H = xgi.chung_lu_hypergraph(k1, k2)"
+    "n = 100\n",
+    "H = xgi.random_hypergraph(100, [0.03, 0.0002, 0.00001])"
    ]
   },
   {
@@ -244,7 +242,42 @@
    "source": [
     "plt.figure(figsize=(10,10))\n",
     "ax = plt.subplot(111)\n",
-    "xgi.draw(H, pos, node_size = 0.01, ax=ax)"
+    "xgi.draw(H, pos, node_size = 5, ax=ax)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "39e2d438",
+   "metadata": {},
+   "source": [
+    "We can even size/color the nodes by their degree!"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "d741e39e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "d = H.nodes.degree\n",
+    "s = 10\n",
+    "node_size = {id: np.sqrt((val+1)*s) for id, val in d.asdict().items()}\n",
+    "c = plt.cm.Blues\n",
+    "cmap = [c(i) for i in np.linspace(0.1, 0.9, d.max() + 1)]\n",
+    "node_fc = {id: np.array(cmap[val]).reshape(1, -1) for id, val in d.asdict().items()}"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "03902a8e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "plt.figure(figsize=(10,10))\n",
+    "ax = plt.subplot(111)\n",
+    "xgi.draw(H, pos, node_size = node_size, node_fc=node_fc, ax=ax)"
    ]
   },
   {
@@ -277,7 +310,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "Python 3.10.4 ('hypergraph')",
    "language": "python",
    "name": "python3"
   },
@@ -291,7 +324,12 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.9"
+   "version": "3.10.4"
+  },
+  "vscode": {
+   "interpreter": {
+    "hash": "fdeb83b6e5b2333358b6ba79181fac315f1a722b4574d7079c134c9ae27f7c53"
+   }
   }
  },
  "nbformat": 4,

xgi/drawing/layout.py

@@ -231,7 +231,7 @@ def weighted_barycenter_spring_layout(H, return_phantom_graph=False):
     except ValueError:
         # The list of node-labels has no integers, so I start from 0
         phantom_node_id = 0
-    
+
     # Looping over the hyperedges of different order (from triples up)
     for d in range(2, max_edge_order(H) + 1):
         # Hyperedges of order d (d=2: triplets, etc.)