Conflicting directionality of constraint and variable value diff

When you diff two models, the directionality (+/-) is opposite between the Constraint Differences and the Relative/Absolute Differences. I read sol2.diff(sol1) as what is the diff going sol1 --> sol2. See in the trivial example below that the Constraint Difference makes it look like the additional constraint has gone away (when it’s in fact the inverse) whereas the solution value has increased 100% (which it has).

In [1]: from gpkit import Variable, Model                                                                                                                      

In [2]: x = Variable("x")                                                                                                                                      

In [3]: m1 = Model(x, [x >= 1])                                                                                                                                

In [4]: sol1 = m1.solve()                                                                                                                                      
Solving took 0.151 seconds.

In [5]: m2 = Model(x, [x >= 1, x >= 2])                                                                                                                        

In [6]: sol2 = m2.solve()                                                                                                                                      
Solving took 0.177 seconds.

In [7]: print(sol2.diff(sol1))                                                                                                                                 
Solution Diff
=============
(positive means the argument is smaller)

Constraint Differences
**********************
--- removed in argument
+++ added in argument

@@ -6,4 +6,3 @@
 Constraints
 -----------
  x >= 1
- x >= 2

**********************

Relative Differences |above 1%|
-------------------------------
x : +100.0%

Basically comes down to the slight contradiction between (positive means the argument is smaller) and +++ added in argument.

[bqpd]

d’oh I should have tried writing it out, that does work well. will implement!

[pgkirsch]

Thanks!