Return physical memory usage (float)
    Requires the cross-platform psutil (>=v0.3) library
    (https://github.com/giampaolo/psutil)

def psutil_phymem_usage():
    """
    Return physical memory usage (float)
    Requires the cross-platform psutil (>=v0.3) library
    (https://github.com/giampaolo/psutil)
    """
    import psutil
    # This is needed to avoid a deprecation warning error with
    # newer psutil versions
    try:
        percent = psutil.virtual_memory().percent
    except:
        percent = psutil.phymem_usage().percent
    return percent