desimodel

Introduction

This product contains information about DESI hardware designs in machine readable formats to be used by simulations. It is intended to be correct but non-authoritative. If in question, the DocDB version of a design parameter is correct. This is intended to reflect the same information while being more conveniently organized and formatted for simulations.

PLEASE KEEP THIS FILE IN SYNC WITH THE EQUIVALENT FILE IN SVN.

Desimodel Code

The svn product described below contains only the data associated with desimodel. The code is in Github: https://github.com/desihub/desimodel.

Desimodel Data

Getting the Data

The data that accompanies the desimodel code is not stored with the code. Due to its size, it is kept in the DESI svn repository. The public, read-only URL for svn access is https://desi.lbl.gov/svn/code/desimodel, with the usual trunk/, tags/ and branches/ directories.

Once you have installed this package, using either pip or desiInstall, there are two ways to install the accompanying data. For most every case, you should install the tag in svn that corresponds to the same tag in git.

There are two methods to install the data, "by hand" and "scripted."

For "by hand" installs:

1. Find the tag you are interested in:

      svn ls https://desi.lbl.gov/svn/code/desimodel/tags
   
   We'll use ``0.10.3`` in the examples below.
   

2. Define the environment variable DESIMODEL:

   export DESIMODEL=/Users/desicollaborator/Data/desimodel/0.10.3
   

   Note how the tag name is included.

3. Create the directory and switch to it:

   mkdir -p $DESIMODEL
   cd $DESIMODEL
   

4. Export:

   svn export https://desi.lbl.gov/svn/code/desimodel/tags/0.10.3/data
   

   Note how the tag name is the same as in the DESIMODEL variable.

5. You may now want to add DESIMODEL to your shell startup scripts.

For "scripted" installs:

• Installing this package will create the command-line script install_desimodel_data. It should appear in your PATH assuming a successful install. install_desimodel_data --help will show you how to use this script. Basically it is just a wrapper on the "by hand" method described above.
• You can also call the function desimodel.install.install() from inside other Python code.

Regardless of which method you choose, you should set the DESIMODEL environment variable to point to the directory containing the data/ directory. The only real difference among all these methods is exactly when you define the DESIMODEL variable.

Data Files

Files in data/inputs/ are copied from DocDB and are not intended to be used directly. These are parsed and reformatted to produce files in other data/ directories which are for use.

data/desi.yaml

Basic scalar parameters, organized in a nested tree.

data/focalplane/

Information about positioner locations and platescale.

data/footprint/

The areas of the sky that will be observed by DESI, with RA, Dec of tiles.

data/sky/

Sample sky spectra.

data/specpsf/

Spectrograph point-spread-function (PSF) for specter CCD pixel-level simulations.

data/spectra/

Example benchmark spectra.

data/targets/

Expected n(z) information per target class for cosmology projections.

data/throughput/

Throughput versus wavelength (also contained in specpsf).

data/weather/

Historical weather data.

Branches

There are several permanent branches that were used for testing alternative designs. Some of these will never be merged into trunk but we will keep them around for the record:

altccd

500 micron versus 250 micron thick CCDs.

bb

Recreating assumptions used during early BigBOSS projections.

newtiles

An improved tiling dither pattern from Eddie Schlafly, intended to be merged prior to the start of the DESI survey.

update_inputs

This branch might be present during updates to the inputs to the desimodel data files. See the updating desimodel inputs document for further details.

In addition to these historical branches, there are a set of test-* branches that contain smaller versions of the desimodel files. These branches are intended for use in desimodel unit tests. See the desimodel testing document for further details.

Tagging

If either the data or the code changes, a new tag should be created in both git and svn.

Full Documentation

Please visit desimodel on Read the Docs

License

desimodel is free software licensed under a 3-clause BSD-style license. For details see the LICENSE.rst file.