Improve sankey logging.

anntzer · anntzer · commit 57c3e1b6c7a6 · 2019-01-20T11:09:13.000+01:00
Running the sankey_rankine example with an info-level logger on emits a
bunch of logs of the form

&gt; The scaled sum of the inputs is 0.039204.
&gt; This may cause poor layout.
&gt; Consider changing the scale so that the scaled sum is approximately 1.0.

but they are clearly intended as such (some flows are just very small,
and they render fine).  Remove that log.

There are also some logs of the form

&gt; The sum of the flows is nonzero (-0.002000).
&gt; Is the system not at steady state?

Improve them by including the patchlabel, so that one can more easily
figure out the potentially incorrect flow values (one now gets

&gt; The sum of the flows is nonzero (-0.002000; patchlabel='\n\nOpen\nheater'); is the system not at steady state?

) (as for the actual values in the example, I guess someone should check
the reference the data comes from).
diff --git a/examples/specialty_plots/sankey_rankine.py b/examples/specialty_plots/sankey_rankine.py
@@ -3,10 +3,9 @@
 Rankine power cycle
 ===================
 
-Demonstrate the Sankey class with a practical example of a Rankine power
-cycle.
-
+Demonstrate the Sankey class with a practical example of a Rankine power cycle.
 """
+
 import matplotlib.pyplot as plt
 
 from matplotlib.sankey import Sankey
diff --git a/lib/matplotlib/sankey.py b/lib/matplotlib/sankey.py
@@ -464,21 +464,12 @@ def add(self, patchlabel='', flows=None, orientations=None, labels='',
                 "'trunklength' is negative, which is not allowed because it "
                 "would cause poor layout")
         if np.abs(np.sum(flows)) > self.tolerance:
-            _log.info("The sum of the flows is nonzero (%f).\nIs the "
-                      "system not at steady state?", np.sum(flows))
+            _log.info("The sum of the flows is nonzero (%f; patchlabel=%r); "
+                      "is the system not at steady state?",
+                      np.sum(flows), patchlabel)
         scaled_flows = self.scale * flows
         gain = sum(max(flow, 0) for flow in scaled_flows)
         loss = sum(min(flow, 0) for flow in scaled_flows)
-        if not (0.5 <= gain <= 2.0):
-            _log.info(
-                "The scaled sum of the inputs is %f.\nThis may "
-                "cause poor layout.\nConsider changing the scale so"
-                " that the scaled sum is approximately 1.0.", gain)
-        if not (-2.0 <= loss <= -0.5):
-            _log.info(
-                "The scaled sum of the outputs is %f.\nThis may "
-                "cause poor layout.\nConsider changing the scale so"
-                " that the scaled sum is approximately 1.0.", gain)
         if prior is not None:
             if prior < 0:
                 raise ValueError("The index of the prior diagram is negative")
