use bz2 compressed pickles

gpkit/__init__.py

@@ -12,6 +12,7 @@
 from .constraints.sigeq import SignomialEquality
 from .constraints.set import ConstraintSet
 from .constraints.model import Model
+from .solution_array import SolutionArray
 from .tools.docstring import parse_variables
 from .tests.run_tests import run as run_unit_tests
 

gpkit/solution_array.py

@@ -4,6 +4,8 @@
 from operator import sub
 import warnings as pywarnings
 import pickle
+import bz2
+import _pickle as cPickle
 import numpy as np
 from .nomials import NomialArray
 from .small_classes import DictOfLists, Strings
@@ -419,6 +421,16 @@ def save(self, filename="solution.pkl", **pickleargs):
         """
         pickle.dump(self, open(filename, "wb"), **pickleargs)
 
+    def save_compressed(self, title="solution", **cpickleargs):
+        "Pickle a file and then compress it into a file with extension."
+        with bz2.BZ2File(title + ".pbz2", "w") as f:
+            cPickle.dump(self, f, **cpickleargs)
+
+    @staticmethod
+    def decompress_file(file):
+        "Load any compressed pickle file"
+        return cPickle.load(bz2.BZ2File(file, "rb"))
+
     def varnames(self, showvars, exclude):
         "Returns list of variables, optionally with minimal unique names"
         if showvars: