Cython in Ipython: ERROR: Cell magic `%%cython` not found

What the warning is trying to communicate is that the extension defining the %%cython magic has moved to the Cython package, out of the IPython package. So instead of

%load_ext cythonmagic

you should do:

%load_ext Cython

After that, the cython magic should work as expected.

Remember to load the extension in a different cell.

If you load and use the Cython extension in the same cell, you will fall in error:

Using the same cell:

Using a different cell: