fix sankey diagrams

docs/source/examples/performance_modeling.py

@@ -255,3 +255,9 @@ def setup(self):
 M.append(MISSION.fs.aircraftp.Wburn >= 0.2*MISSION.fs.aircraftp.wing_aero.D)
 sol = M.solve(verbosity=0)
 print(sol.diff("solution.pkl", showvars=vars_of_interest, sortbymodel=False))
+
+# this will only make an image when run in jupyter notebook
+from gpkit.interactive.sankey import Sankey
+sankey = Sankey(sol, M).diagram(left=40, width=950, right=150)
+sankey.auto_save_svg("performance_modeling.svg")
+sankey

docs/source/modelbuilding.rst

@@ -88,8 +88,13 @@ In the example below, the models ``Aircraft`` and ``Wing`` have a ``.dynamic()``
 
 This means that when an aircraft is being optimized for a mission, you can create the aircraft (``AC`` in this example) and then pass it to a ``Mission`` model which can create vectorized aircraft performance models for each flight segment and/or flight condition.
 
+The :ref:`sensitivity diagram <sankey>` which this code outputs shows how it is organized:
+
+.. figure:: figures/sankey/performance_modeling.svg
+    :width: 700 px
+
 .. literalinclude:: examples/performance_modeling.py
 
-Note that the output table can be filtered with a list of variables to show.
+Note that the output table has been filtered above to show only variables of interest.
 
 .. literalinclude:: examples/performance_modeling_output.txt

docs/source/visint.rst

@@ -1,8 +1,9 @@
 Visualization and Interaction
 *****************************
 
-Sankey Diagrams
-===============
+.. _sankey:
+Sensitivity Diagrams
+====================
 
 Requirements
 ------------
@@ -31,13 +32,13 @@ Code in this section uses the `CE solar model <https://github.com/convexengineer
 ::
 
     (objective) adds +1 to the sensitivity of Wtotal_Aircraft
-    (objective) is Wtotal_Aircraft [lbf] 
+    (objective) is Wtotal_Aircraft [lbf]
 
     Ⓐ adds +0.0075 to the overall sensitivity of Wtotal_Aircraft
-    Ⓐ is Wtotal_Aircraft <= 0.5*CL_Mission/Climb/AircraftDrag/WingAero_(0,)*S_Aircraft/Wing/Planform.2*V_Mission/Climb_(0, 0)**2*rho_Mission/Climb_(0, 0) 
+    Ⓐ is Wtotal_Aircraft <= 0.5*CL_Mission/Climb/AircraftDrag/WingAero_(0,)*S_Aircraft/Wing/Planform.2*V_Mission/Climb_(0, 0)**2*rho_Mission/Climb_(0, 0)
 
     Ⓑ adds +0.0117 to the overall sensitivity of Wtotal_Aircraft
-    Ⓑ is Wtotal_Aircraft <= 0.5*CL_Mission/Climb/AircraftDrag/WingAero_(1,)*S_Aircraft/Wing/Planform.2*V_Mission/Climb_(0, 1)**2*rho_Mission/Climb_(0, 1) 
+    Ⓑ is Wtotal_Aircraft <= 0.5*CL_Mission/Climb/AircraftDrag/WingAero_(1,)*S_Aircraft/Wing/Planform.2*V_Mission/Climb_(0, 1)**2*rho_Mission/Climb_(0, 1)
 
 
 Explanation
@@ -95,23 +96,6 @@ Sankey(M).diagram(M['vgust'])
     :width: 700 px
 
 
-Equivalent Variables
-^^^^^^^^^^^^^^^^^^^^
-
-If any variables are equal to the diagram's variable (modulo some
-constant factor; e.g. ``2*x == y`` counts for this, as does ``2*x <= y``
-if the constraint is sensitive), they are found and plotted
-at the same time, and all shown on the left. The constraints responsible
-for this are shown next to their labels.
-
-.. code:: python
-
-    Sankey(M).sorted_by('constraints', 11)
-
-.. figure:: figures/sankey/solar_tmin.svg
-    :width: 700 px
-
-
 Models
 ~~~~~~
 

gpkit/constraints/costed.py

@@ -2,6 +2,7 @@
 import numpy as np
 from .set import ConstraintSet
 from ..small_scripts import maybe_flatten
+from ..repr_conventions import lineagestr
 
 
 class CostedConstraintSet(ConstraintSet):
@@ -33,12 +34,14 @@ def constrained_varkeys(self):
 
     def _rootlines(self, excluded=()):
         "String showing cost, to be used when this is the top constraint"
-        description = ["", "Cost", "----",
-                       " %s" % self.cost.str_without(excluded),
-                       "", "Constraints", "-----------"]
+        if self.cost.varkeys:
+            description = ["", "Cost", "----",
+                           " %s" % self.cost.str_without(excluded),
+                           "", "Constraints", "-----------"]
+        else:
+            description = ["", "Constraints", "-----------"]
         if self.lineage:
-            name, num = self.lineage[-1]  # pylint: disable=unsubscriptable-object
-            fullname = "%s" % (name if not num else name + str(num))
+            fullname = lineagestr(self)
             description = [fullname, "="*len(fullname)] + description
         return description
 

gpkit/constraints/set.py

@@ -1,4 +1,5 @@
 "Implements ConstraintSet"
+import sys
 from collections import defaultdict, OrderedDict
 from itertools import chain
 import numpy as np
@@ -36,7 +37,7 @@ def _sort_constraints(item):
 
 def sort_constraints_dict(iterable):
     "Sort a dictionary of {k: constraint} and return its keys and values"
-    if isinstance(iterable, OrderedDict):
+    if sys.version_info >= (3, 7) or isinstance(iterable, OrderedDict):
         return iterable.keys(), iterable.values()
     items = sorted(list(iterable.items()), key=_sort_constraints)
     return (item[0] for item in items), (item[1] for item in items)