desimodel 0.20.0

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, the associated data must also be installed. For most every case, you should install the tag in svn that corresponds to the same tag in git.

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.

You can also call the function desimodel.install.install() from inside other Python code.

When desimodel is used with other downstream code, it might become necessary to set the environment variable DESIMODEL. You should set the DESIMODEL environment variable to point to the directory containing the data/ directory.

install_desimodel_data with default options, may install the data in a relatively obscure location. To find the value to set for DESIMODEL, you can do the following:

python -c "from importlib.resources import files; print(str(files('desimodel')))"

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.