ENH(plot): option to not group plots in postage stamps (#45)

Add a new `group=` parameter to `postage_stamps()` that controls whether
or not plots are grouped by their bin indices. For `group=False`, all
combinations are separated into a triangular plot.

Also fixes a number of bugs and inconsistencies in the plotting routine.

Closes: #44

heracles/plot.py

@@ -18,7 +18,7 @@
 # License along with Heracles. If not, see <https://www.gnu.org/licenses/>.
 """utility functions for plotting"""
 
-from collections import defaultdict
+from collections import Counter, defaultdict
 from collections.abc import Mapping
 from itertools import chain, count, cycle
 
@@ -65,6 +65,7 @@ def postage_stamps(
     hatch_empty=False,
     linscale=0.01,
     cycler=None,
+    group=True,
 ):
     """create a postage stamp plot for cls"""
 
@@ -89,26 +90,30 @@ def postage_stamps(
     else:
         trkeys = {}
 
-    stamps = sorted(
-        set(key[-2:] for key in keys) | set(key[-2:][::-1] for key in trkeys),
-    )
-
-    sx = list(set(i for i, _ in stamps))
-    sy = list(set(j for _, j in stamps))
+    # either group the plots by last two indices or not
+    # uses Counter as a set that remembers order
+    if group:
+        si = list(Counter(key[-2] for key in keys))
+        sj = list(Counter(key[-1] for key in keys))
+        ti = list(Counter(key[-2] for key in trkeys))
+        tj = list(Counter(key[-1] for key in trkeys))
+    else:
+        si = sj = list(Counter(key[k::2] for key in keys for k in (0, 1)))
+        ti = tj = list(Counter(key[k::2] for key in trkeys for k in (0, 1)))
 
-    nx = len(sx)
-    ny = len(sy)
+    nx = max(len(si), len(tj))
+    ny = max(len(sj), len(ti))
 
     if trkeys:
         nx += trxshift
         ny += tryshift
 
-    figw = (ny + (ny - 1) * space) * stampsize
-    figh = (nx + (nx - 1) * space) * stampsize
+    figw = (nx + (nx - 1) * space) * stampsize
+    figh = (ny + (ny - 1) * space) * stampsize
 
     fig, axes = plt.subplots(
-        nx,
         ny,
+        nx,
         figsize=(figw, figh),
         squeeze=False,
         sharex=False,
@@ -129,11 +134,19 @@ def postage_stamps(
         ki, kj, i, j = key
 
         if n < len(keys):
-            idx = (sx.index(j) + trxshift, sy.index(i))
+            if group:
+                idx_y, idx_x = sj.index(j), si.index(i)
+            else:
+                idx_x, idx_y = sorted([si.index((ki, i)), sj.index((kj, j))])
+            idx = (idx_y + tryshift, idx_x)
             cls = (x.get(key) for x in plot)
             axidx.add(idx)
         else:
-            idx = (sx.index(i), sy.index(j) + tryshift)
+            if group:
+                idx_y, idx_x = ti.index(i), tj.index(j)
+            else:
+                idx_y, idx_x = sorted([ti.index((ki, i)), tj.index((kj, j))])
+            idx = (idx_y, idx_x + trxshift)
             cls = (x.get(key) for x in transpose)
             traxidx.add(idx)
 
@@ -185,9 +198,9 @@ def postage_stamps(
             label = None
 
     xmin, xmax = _pad_xlim(xmin, xmax)
-    ymin, ymax = _pad_ylim(ymin, ymax)
-    ylin = 10 ** np.ceil(np.log10(max(abs(ymin), abs(ymax)) * linscale))
-
+    if keys:
+        ymin, ymax = _pad_ylim(ymin, ymax)
+        ylin = 10 ** np.ceil(np.log10(max(abs(ymin), abs(ymax)) * linscale))
     if trkeys:
         trymin, trymax = _pad_ylim(trymin, trymax)
         trylin = 10 ** np.ceil(np.log10(max(abs(trymin), abs(trymax)) * linscale))
@@ -210,9 +223,9 @@ def postage_stamps(
             left=True,
             right=True,
             labeltop=(idx[0] == 0),
-            labelbottom=(idx[0] == nx - 1),
+            labelbottom=(idx[0] == ny - 1),
             labelleft=(idx[1] == 0),
-            labelright=(idx[1] == ny - 1),
+            labelright=(idx[1] == nx - 1),
         )
         ax.set_axisbelow(False)
 

tests/test_plot.py

@@ -21,14 +21,14 @@ def test_postage_stamps():
         ("P", "P", 1, 1): cl,
     }
 
-    fig = postage_stamps(plot, transpose, trxshift=3, tryshift=2, hatch_empty=True)
+    fig = postage_stamps(plot, transpose, trxshift=2, tryshift=3, hatch_empty=True)
 
     assert len(fig.axes) == 5 * 4
 
     axes = np.reshape(fig.axes, (5, 4))
 
-    for i in range(5):  # rows: 2 + trxshift
-        for j in range(4):  # columns: 2 + tryshift
+    for i in range(5):  # rows: 2 + tryshift
+        for j in range(4):  # columns: 2 + trxshift
             lines = axes[i, j].get_lines()
             if i - j > 2:
                 assert len(lines) == 2  # E, B in lower