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Interactive data analysis with iPython

Many users are familiar with matlab, which is not supported by the LCLS offline group. This is a description of how you can use interactive python to analyze your data in a very similar way.

Many thanks to the XPP crew, Henrik Lemke in particular, for providing guidance, code examples (in matlab) and feedback in writing the python scripts presented here.

The components

  • matplotlib pyplot / pylab
    ... an open-source plotting tool

The Matlab-like tools / library provided by PCDS

  • matlab.py
    ... a module implementing in python some of the tools written by Henrik/XPP for matlab
    Starting iPython
    [ofte@psana0XXX myrelease]$ ipython
Python 2.4.3 (#1, Nov  3 2010, 12:52:40)
Type "copyright", "credits" or "license" for more information.

IPython 0.9.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

    Loading the library
    In [1]: import matlab
Pretend this is matlab
In [2]:

    who and whos
    In [2]: who
matlab                                                            # who gives you a brief list of your workspace contents

In [3]: whos
Variable   Type      Data/Info                                    # whos gives you a longer list of your workspace contents
------------------------------
matlab     module    <module 'matlab' from 'matlab.py'>

In [4]:

    more about a module
    In [4]: matlab.<TAB>                                              # write matlab. and hit the TAB button to see available functions in matlab.py
matlab.__builtins__                    matlab.__hash__
matlab.__class__                       matlab.__init__
matlab.__delattr__                     matlab.__name__
matlab.__dict__                        matlab.__new__
matlab.__doc__                         matlab.np
matlab.__file__                        matlab.plt
matlab.filtvec                         matlab.py
matlab.findmovingmotor                 matlab.py~
matlab.__getattribute__                matlab.pyc
matlab.get_filter                      matlab.rdXPPdata
matlab.get_limits                      matlab.__reduce__
matlab.get_limits_automatic            matlab.__reduce_ex__
matlab.get_limits_channelhist          matlab.__repr__
matlab.get_limits_correlation          matlab.runexpNO2fina
matlab.get_limits_corrfrac             matlab.ScanInput
matlab.getSTDMEANfrac_from_startpoint  matlab.ScanOutput
matlab.H5getobjnames                   matlab.__setattr__
matlab.h5py                            matlab.__str__

    after editing
    In [5]: reload matlab  
-------> reload(matlab)                                           # if you edited matlab.py, reload it before you continue
Pretend this is matlab
Out[15]: <module 'matlab' from 'matlab.py'>

Examples

1) Select limits from graphical input and plot filtered IPIMB

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