LES python seminar series (Thursday, 10:30 - 12:00, Geomatikum, 1729)

contact: Alex Loew, Julia Pongratz

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What you should be able to do in advance

• python programming structures
• if clauses
• function calling
• print statements
• well, running python scripts (in python shell and interactive shell like ipython)
• edit python scripts in the editor of your choice
• ...

Seminar outline

Part 1

Working with arrays (Gernot, Michael) (19.07.2012)

• Commented examples from the seminar

• general information on python data model (copy, references, deepcopy)

• map and lambda functions

• numpy arrays (indexing, slicing, views ...)

• array functions (mean, sum etc. along axes)
  • data type conversions

  • elementwise functions

  • linear algebra

  • array statistics

• masked arrays

• reading ASCII files etc.

  • numpy input and output

  • general input and output (opening a file and working with a file)

• pickle, cPickle

Plotting (1D,2D,3D) (Alex) (2.8.2012)

Course material for plotting

* subplots, figure, axis objects; easy and more sophisticated appraoches

• always use figure/ax

• a brief tour through matplotlib gallery

  • lineplots
  • fill_between
  • contour plots
• nice colorbars, colormaps handling etc.
• working with different axes in a single plot; twinx()
• saving figures
  • fitting to actual content

• tight_layout

Geospatial data format handling and vizualization (Mikhail) (16.08.2012)

Lesson code examples

• PyNio - handling netCDF

  • read netCDF
  • write netCDF
    • data type conversion
      • how to write a numpy array (double) in a float netcdf variable?
      • how to store data as scaled integers?

• GDAL: the door to a huge number of different file formats. GDAL (Python) API tutorial

• Basemap

• PyNGL Tutorial

system operations (Michael) (30.8.2012)

Commented examples from the seminar

• replacing BASH: working with os and system objects
• os.system, subprocess etc.
• python as a replacement for bash
• how to debug a python program?

Structuring a program (Mikhail) (13.9.2012)

Commented program from the seminar

• general structure of python scripts
• writing python functions, what are the keyworded and the non-keyworded arguments
• writing modules and classes, why and how to create custom objects
• naming convention
• how to parse command line input for options and arguments

Part 2

pyCMBS (Alex) (31.10. as part of the Wednsday seminar)

• introduction to pyCMBS
• cdo interfacing
• anomaly calculations, hovmoeller plots etc ...
• EOF, SVD analysis

time series analysis: the Pandas module (Mikhail) (25.10.)

Lesson code

• Indexed arrays
• Merging, aligning and restructuring timeseries
• Reindexing timeseries

• Video tutorial by Wes McKinney

• Official site with documentation

parallel programming (Heinrich Widmann) (08.11.)

Lesson code ... and slides

• Threading vs. multiprocessing
  • The GIL issue

• ParallelPython module (pp)

• Processing module
• Further approaches and techniques ...
• Not (really) addressed :
  • openMP, MPI
  • more sophuisticated clustering, scheduling and load balancing ....

• Ian Ozsvald's lesson at SciPy2012

python CDO interface (Ralf Mueller) (22.11.)

• cdo - python/ruby interface

Integration of other programming languages (Nikolay Koldunov, Mikhail Itkin, 06.12)

• Ipython Notebook Ipython lesson notebook

• f2py | f2py lesson code

• R and Python tutorials:

  • rpy2: Accessing R from Python video tutorial

  • Gentle RPY2 tutorial

• Python integration with other languages

• Bonus: Pyresample- reprojection of geospatial data

Tips and Tricks

• Spearman rank correlation revisited in python

other topics

• statistical analysis of large data sets
• animations
• GUI programming (Alex, remon???)
• H5PY - simple access to HDF5 files
• python2.x or python3.x (does it make a difference?)