add constraint differences

docs/source/examples/performance_modeling_output.txt

@@ -102,6 +102,18 @@ Solution difference for selected variables
 ==========================================
 (positive means the argument is smaller)
 
+Constraint differences
+**********************
+
+--- removed in argument
++++ added in argument
+@@ -41,4 +41,3 @@
+          c = (S/A)^0.5
+        "parametrization of wing weight":
+          Aircraft.Wing.W >= S·Aircraft.Wing.rho
+- Wburn[:] >= 0.2·D[:]
+**********************
+
 Relative differences >1%
 ------------------------
 Wburn : [ +102.1%   +101.6%   +101.1%   +100.5%  ] segment fuel burn
@@ -110,5 +122,5 @@ Wfuel : [ +101.3%   +101.1%   +100.8%   +100.5%  ] fuel weight
 
 Sensitivity differences >0.1
 ----------------------------
-The largest is -0.00451643
+The largest is -0.00451643.
 

docs/source/examples/simpleflight_output.txt

@@ -40,11 +40,11 @@ Solution difference
 
 Relative differences >1%
 ------------------------
-The largest is 0%
+The largest is +0%.
 
 Sensitivity differences >0.1
 ----------------------------
-The largest is +0
+The largest is +0.
 
 SWEEP
 =====

gpkit/solution_array.py

@@ -1,5 +1,6 @@
 """Defines SolutionArray class"""
 import re
+import difflib
 from operator import sub
 import warnings as pywarnings
 import pickle
@@ -342,6 +343,14 @@ def diff(self, other, showvars=None, *, senssdiff=True, sensstol=0.1,
             showvars = self._parse_showvars(showvars)
             svks = {k for k in showvars if k in svars}
             ovks = {k for k in showvars if k in ovars}
+        if self.modelstr != other.modelstr:
+            lines += ["Constraint differences",
+                      "**********************", ""]
+            lines.extend(difflib.unified_diff(
+                self.modelstr.split("\n"), other.modelstr.split("\n"),
+                fromfile="removed in argument", tofile="added in argument",
+                lineterm="", n=3))
+            lines += ["**********************", ""]
         if svks - ovks:
             lines.append("Variable(s) of this solution"
                          " which are not in the argument:")
@@ -361,7 +370,7 @@ def diff(self, other, showvars=None, *, senssdiff=True, sensstol=0.1,
                                valfmt="%+.1f%%  ", vecfmt="%+6.1f%% ",
                                minval=reltol, printunits=False, **tableargs)
             if lines[-2][:10] == "-"*10:  # nothing larger than sensstol
-                lines.insert(-1, ("The largest is %g%%"
+                lines.insert(-1, ("The largest is %+g%%."
                                   % unrolled_absmax(rel_diff.values())))
         # absolute difference #
         if absdiff:
@@ -370,7 +379,7 @@ def diff(self, other, showvars=None, *, senssdiff=True, sensstol=0.1,
                                valfmt="%+.2g", vecfmt="%+8.2g",
                                minval=abstol, **tableargs)
             if lines[-2][:10] == "-"*10:  # nothing larger than sensstol
-                lines.insert(-1, ("The largest is %+g"
+                lines.insert(-1, ("The largest is %+g."
                                   % unrolled_absmax(abs_diff.values())))
         # sensitivity difference #
         if senssdiff:
@@ -383,7 +392,7 @@ def diff(self, other, showvars=None, *, senssdiff=True, sensstol=0.1,
                                valfmt="%+-.2f  ", vecfmt="%+-6.2f",
                                minval=sensstol, printunits=False, **tableargs)
             if lines[-2][:10] == "-"*10:  # nothing larger than sensstol
-                lines.insert(-1, ("The largest is %+g"
+                lines.insert(-1, ("The largest is %+g."
                                   % unrolled_absmax(senss_delta.values())))
         return "\n".join(lines)