Add type checks

nifty6/operators/simple_linear_operators.py

@@ -11,19 +11,19 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
-# Copyright(C) 2013-2019 Max-Planck-Society
+# Copyright(C) 2013-2020 Max-Planck-Society
 #
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
+import numpy as np
+
 from ..domain_tuple import DomainTuple
-from ..multi_domain import MultiDomain
 from ..domains.unstructured_domain import UnstructuredDomain
 from ..field import Field
+from ..multi_domain import MultiDomain
 from ..multi_field import MultiField
-from .linear_operator import LinearOperator
 from .endomorphic_operator import EndomorphicOperator
-from .. import utilities
-import numpy as np
+from .linear_operator import LinearOperator
 
 
 class VdotOperator(LinearOperator):
@@ -128,7 +128,11 @@ class Imaginizer(EndomorphicOperator):
     def apply(self, x, mode):
         self._check_input(x, mode)
         if mode == self.TIMES:
+            if not np.issubdtype(x.dtype, np.complexfloating):
+                raise ValueError
             return x.imag
+        if x.dtype not in (np.float64, np.float32):
+            raise ValueError
         return 1j*x