Merge pull request #321 from drhodes/master

lazily import scipy to avoid import delay

Author: jolyonb

mitxgraders/formulagrader/integralgrader.py

@@ -8,7 +8,6 @@
 
 import six
 from functools import wraps
-from scipy import integrate
 from numpy import real, imag
 from abc import abstractproperty
 from numbers import Number
@@ -517,6 +516,9 @@ def raw_integrand(x):
                                  suffixes=self.suffixes)
             return value
 
+        # lazy load this module for performance reasons
+        from scipy import integrate
+
         if self.config['complex_integrand']:
             integrand_re = lambda x: real(raw_integrand(x))
             integrand_im = lambda x: imag(raw_integrand(x))

mitxgraders/helpers/calc/mathfuncs.py

@@ -17,7 +17,6 @@
 import six
 from numbers import Number
 import numpy as np
-import scipy.special as special
 from mitxgraders.helpers.calc.specify_domain import SpecifyDomain
 from mitxgraders.helpers.calc.exceptions import FunctionEvalError
 from mitxgraders.helpers.calc.math_array import MathArray
@@ -208,6 +207,9 @@ def factorial(z):
                "functions cannot be used at negative integer values.")
         raise FunctionEvalError(msg)
 
+    # lazy import this module for performance reasons
+    import scipy.special as special
+
     value = special.gamma(z+1)
     # value is a numpy array; If it's 0d, we can just get its item:
     try:

mitxgraders/matrixsampling.py

@@ -29,12 +29,6 @@ def rvs(self, dimension):
         raise NotImplementedError('This feature requires newer versions of numpy '
                                   'and scipy than are available.')
 
-try:
-    from scipy.stats import ortho_group, special_ortho_group, unitary_group
-except ImportError:
-    ortho_group = Unavailable()
-    special_ortho_group = Unavailable()
-    unitary_group = Unavailable()
 
 # Set the objects to be imported from this grader
 __all__ = [
@@ -825,6 +819,13 @@ def generate_sample(self):
         """
         Generates an orthogonal matrix
         """
+        # lazy load this module for performance reasons
+        try:
+            from scipy.stats import ortho_group, special_ortho_group
+        except ImportError:
+            ortho_group = Unavailable()
+            special_ortho_group = Unavailable()
+
         # Generate the array
         if self.config['unitdet']:
             array = special_ortho_group.rvs(self.config['dimension'])
@@ -896,6 +897,12 @@ def generate_sample(self):
         """
         Generates an orthogonal matrix as appropriate
         """
+        # lazy load this module for performance reasons
+        try:
+            from scipy.stats import unitary_group
+        except ImportError:
+            unitary_group = Unavailable()
+
         # Generate the array
         array = unitary_group.rvs(self.config['dimension'])
         # Fix the determinant if need be