%pylab inline in IPYTHON notebook throws "RuntimeError: Cannot activate multiple GUI eventloops"

[divaDevDir]

I am on IPython 0.13.2 in Windows XP (32 bit)

If I start through the command "ipython notebook", A cell with "%pylab inline" throws the below error.

Welcome to pylab, a matplotlib-based Python environment [backend: module://IPython.zmq.pylab.backend_inline].
For more information, type 'help(pylab)'.
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-1-550caa57204a> in <module>()
----> 1 get_ipython().magic(u'pylab inline')

C:\Python27\Lib\site-packages\IPython\core\interactiveshell.pyc in magic(self, arg_s)
   2134         magic_name, _, magic_arg_s = arg_s.partition(' ')
   2135         magic_name = magic_name.lstrip(prefilter.ESC_MAGIC)
-> 2136         return self.run_line_magic(magic_name, magic_arg_s)
   2137 
   2138     #-------------------------------------------------------------------------

C:\Python27\Lib\site-packages\IPython\core\interactiveshell.pyc in run_line_magic(self, magic_name, line)
   2060                 args.append(sys._getframe(stack_depth).f_locals)
   2061             with self.builtin_trap:
-> 2062                 result = fn(*args)
   2063             return result
   2064 

C:\Python27\Lib\site-packages\IPython\core\magics\pylab.pyc in pylab(self, parameter_s)

C:\Python27\Lib\site-packages\IPython\core\magic.pyc in <lambda>(f, *a, **k)
    189     # but it's overkill for just that one bit of state.
    190     def magic_deco(arg):
--> 191         call = lambda f, *a, **k: f(*a, **k)
    192 
    193         if callable(arg):

C:\Python27\Lib\site-packages\IPython\core\magics\pylab.pyc in pylab(self, parameter_s)
     86             import_all_status = True
     87 
---> 88         self.shell.enable_pylab(parameter_s, import_all=import_all_status)

C:\Python27\Lib\site-packages\IPython\core\interactiveshell.pyc in enable_pylab(self, gui, import_all)
   2790         # Now we must activate the gui pylab wants to use, and fix %run to take
   2791         # plot updates into account
-> 2792         self.enable_gui(gui)
   2793         self.magics_manager.registry['ExecutionMagics'].default_runner = \
   2794         mpl_runner(self.safe_execfile)

C:\Python27\Lib\site-packages\IPython\zmq\eventloops.pyc in enable_gui(gui, kernel)
    220     loop = loop_map[gui]
    221     if kernel.eventloop is not None and kernel.eventloop is not loop:
--> 222         raise RuntimeError("Cannot activate multiple GUI eventloops")
    223     kernel.eventloop = loop

RuntimeError: Cannot activate multiple GUI eventloops

But If I start through the command "ipython notebook --pylab=inline", A cell with "%pylab inline" works just fine but "%pylab qt" throws the below error.

Welcome to pylab, a matplotlib-based Python environment [backend: Qt4Agg].
For more information, type 'help(pylab)'.
C:\Python27\Lib\site-packages\matplotlib\__init__.py:1033: UserWarning:  This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.

  warnings.warn(_use_error_msg)

Basically I could not change the matplotlib backend dynamically.

[minrk]

It is not recommended to start the notebook with --pylab [anything]. It is best to always use the %pylab magic in the notebooks themselves.

[minrk]

Also, I think support for backend switching may be new in 1.0.

[divaDevDir]

I agree and realize that, backend switching is a feature available only in the new 1.0 version (not in my 0.13.2 version)