Fixes #633

@lamblin . Unit tests to be added.
This will test for only one set of 3 numbers, which will always be the same: xval=0.417022, yval=0.72032449, zval=0.00011437
One way of testing more cases would be to loop over triples of values.
Can you check that the Elemwise version of that scalar Op, is already tested, in tensor/tests/test_basic.py or test_elemwise.py? If so, it may not matter much.