Make a unit file to test if scipy is available.

theano/sandbox/linalg/ops.py

@@ -458,7 +458,9 @@ def diag(x):
         raise TypeError('diag requires vector or matrix argument', x)
 
 class Det(Op):
-    """matrix determinant"""
+    """matrix determinant
+    TODO: move this op to another file that request scipy.
+    """
     def make_node(self, x):
         x = as_tensor_variable(x)
         o = theano.tensor.scalar(dtype=x.dtype)

theano/sandbox/linalg/tests/test_linalg.py

 import numpy
 
 import theano
-import theano.sparse # To know if scipy is available.
+import theano.scipy # To know if scipy is available.
 from theano import tensor, function
 from theano.tensor.basic import _allclose
 
@@ -64,9 +64,7 @@ def test_inverse_grad():
 
 def test_det_grad():
     # If scipy is not available, this test will fail, thus we skip it.
-    # Note that currently we re-use the `enable_sparse` flag, but it may be
-    # cleaner to have a different `scipy_available` flag in the future.
-    if not theano.sparse.enable_sparse:
+    if not theano.scipy.scipy_available:
         raise SkipTest('Scipy is not available')
     rng = numpy.random.RandomState(1234)
 

theano/sparse/__init__.py

 import sys
+import theano.scipy
 
-enable_sparse=True
-
-try:
+enable_sparse = False
+if theano.scipy.scipy_available:
     import scipy
-    if scipy.__version__ < '0.7':
+    if not scipy.__version__ < '0.7':
+        enable_sparse = True
+    else:
         sys.stderr.write("WARNING: scipy version = %s. We request version >=0.7.0 for the sparse code as it has bugs fixed in the sparse matrix code.\n" % scipy.__version__)
-        enable_sparse=False
-except ImportError:
-    enable_sparse=False
+else:
     sys.stderr.write("WARNING: scipy can't be imported. We disable the sparse matrix code.")
+
 if enable_sparse:
     from basic import *
     import sharedvar