If the gpu isn't working don't raise an error uselessly

theano/compile/nanguardmode.py

@@ -113,23 +113,42 @@ class NanGuardMode(Mode):
     """
 
     def __init__(self, nan_is_error, inf_is_error, big_is_error=True):
+        cuda_compile_failed = False
         if cuda.cuda_available:
             self.guard_input = cuda.fvector('nan_guard')
             if nan_is_error or inf_is_error:
+                try:
                     self.gpumin = theano.function(
                         [self.guard_input], T.min(self.guard_input),
                         mode='FAST_RUN'
                     )
-            if inf_is_error:
+                except RuntimeError:
+                    # This can happen if cuda is available, but the
+                    # device is in exclusive mode and used by another
+                    # process.
+                    cuda_compile_failed = True
+            if inf_is_error and not cuda_compile_failed:
+                try:
                     self.gpumax = theano.function(
                         [self.guard_input], T.max(self.guard_input),
                         mode='FAST_RUN'
                     )
-            if big_is_error:
+                except RuntimeError:
+                    # This can happen if cuda is available, but the
+                    # device is in exclusive mode and used by another
+                    # process.
+                    cuda_compile_failed = True
+            if big_is_error and not cuda_compile_failed:
+                try:
                     self.gpuabsmax = theano.function(
                         [self.guard_input], T.max(T.abs_(self.guard_input)),
                         mode='FAST_RUN'
                     )
+                except RuntimeError:
+                    # This can happen if cuda is available, but the
+                    # device is in exclusive mode and used by another
+                    # process.
+                    cuda_compile_failed = True
 
         def do_check_on(var, nd, f, is_input):
             """