Hi Folks, I'm trying to install the development version of yt-2.7 on NERSC's Hopper machine using the install script. I get to the part where it tries to build IPython, and then the script fails with the following error message: ============================================================================ BUILDING IPYTHON python: 2.7.6 (default, Jan 31 2014, 21:52:04) [GCC 4.8.1 20130531 (Cray Inc.)] platform: linux2 OPTIONAL DEPENDENCIES sphinx: Not found (required for docs and nbconvert) pygments: Not found (required for docs and nbconvert) nose: 1.3.0 pexpect: no (required for running standalone doctests) Traceback (most recent call last): File "setup.py", line 342, in <module> check_for_dependencies() File "/global/u2/a/atmyers/yt-x86_64/src/ipython-1.1.0/setupbase.py", line 376, in check_for_dependencies check_for_pyzmq() File "/global/u2/a/atmyers/yt-x86_64/src/ipython-1.1.0/setupext/setupext.py", line 118, in check_for_pyzmq import zmq File "/global/homes/a/atmyers/yt-x86_64/lib/python2.7/site-packages/zmq/__init__.py", line 35, in <module> _libzmq = ctypes.CDLL(bundled[0], mode=ctypes.RTLD_GLOBAL) File "/global/homes/a/atmyers/yt-x86_64/lib/python2.7/ctypes/__init__.py", line 365, in __init__ self._handle = _dlopen(self._name, mode) OSError: /global/homes/a/atmyers/yt-x86_64/lib/python2.7/site-packages/zmq/libzmq.so: undefined symbol: clock_gettime Both ZeroMQ and pyzmq appear to have been installed without errors, but then ZeroMQ can't find some of the definitions it needs. Googling around, it looks like clock_gettime is supposed to be found in librt. Has anyone seen this before? Or, relatedly, has anyone been able to build yt on the NERSC machines? I know that ZeroMQ isn't strictly necessary, but I'd like to be able to use the notebooks. My complete yt_install.log is herehttps://www.dropbox.com/s/pmdq3a9vfrbtwj9/yt_install.log . Thanks, Andrew