Ereline - Planck/LFI calibration pipeline for Erebor

Introduction

Ereline is a re-implementation of the Planck/LFI calibration pipeline. It has been designed for testing different approaches in the calibration and to checking the robustness of LFI's results.

It is written in C++ and accesses data written in FITS format. The current plan is to simulate the following features of the instrument:

• Effect of non-ideal beams in the observation of the sky
• Presence of a Doppler effect due to the satellite's motion
• Time-dependent gain instabilities

Dependencies

The code uses C++11 features, so you need a reasonably recent C++ compiler (GCC 4.8.x is ok).

The code needs the Boost library to compile. Version 1.41 is the oldest one known to be usable with Ereline. The following modules are used:

• Boost::date_time
• Boost::format
• Boost::test (only used by "make check")

Healpix 3.x must be installed and made available to the configure script. The cleanest way to do this is to specify the CPPFLAGS and LDFLAGS variables in the command line used to invoke configure:

./configure CPPFLAGS=-I$HEALPIX/include LDFLAGS=-L$HEALPIX/lib

A MPI library is required as well. To use it, specify CXX=mpic++ in the invocation to "configure", just as above. (Depending on the MPI library you're using, you might need to change mpic++ into mpicxx, mpiCC, or something else).

SQLite3 and GNU GSL are two more needed dependencies. In both cases, the configure script should be smart enough to find them with no user intervention. If not, use the same trick shown above for Healpix (i.e., CPPFLAGS/LDFLAGS).

If you want to build the Developer's manual, you need to install Doxygen as well (http://www.stack.nl/~dimitri/doxygen).

How to compile the code

Download the code to some directory (e.g. /opt/ereline), then run the following commands from your home directory:

$ mkdir ereline_build
$ cd ereline_build
$ /path/to/ereline/source/code/configure \
    --with-boost=PATH_TO_BOOST \
    CPPFLAGS=-I$HEALPIX/include \
    LDFLAGS=-L$HEALPIX/lib CXX=mpic++
$ make
$ make check

(note that you do not have to run configure and make in the same directory as the source code — this allows to keep the source in a read-only folder.)

The last command (make check) is optional: it ensures that the code works as expected by running a number of test programs and checking that their results agrees with the expectations.

How to create the documentation

The User's manual has been written using Sphinx. You will need to install Python 2.7, the Sphinx package (under Debian/Ubuntu, run sudo apt-get install python-sphinx) and the appropriate "readthedocs" style. The latter can be installed using pip:

$ pip install sphinx_rtd_theme

Then, enter the doc/user_manual and issue the command

$ make html

The result will be placed in the directory _build/html/. Unfortunately, at the time the documentation is lagging behind the code.

Development status

Currently the program implements all the δDX11 modules used in the calibration, i.e.:

• Projection of TODs into rings
• Dipole fitting
• Mademoiselle/DaCapo
• δDX11 smoothing

License

We have still to decide which license to use. In the long run, it will probably be an open-source license, but at the moment we want to keep it private until the whole Planck dataset will be released to the public.