extract fiberassign relevant information from surveysim

[forero]

Added a simple script that extracts the information described in #53

[forero]

@dkirkby Do you have any comments about this script?

[dkirkby]

This looks like it probably meets your needs but has several issues if you want to add it to surveysim:

• You are not following the recommended pattern for bin scripts, where most of the functionality lives in a separate scripts module. See bin/surveysim and surveysim.scripts.surveysim for example.
• You are partially reimplementing utility code already provided in desisurvey.config and desisurvey.utils, which makes your code harder to maintain (due to duplication) and more fragile (since you hardcode assumptions that are handled more generally by the existing utilities).

Taking a step back, your code reads progress.fits and exposures.fits and writes:

• exposures_bright|dark.fits
• fiberassign_dates_dark|bright.txt

The latter file only contains dates (YYYY-MM-DD) without identifying which tiles should have FA run on each date. Do you actually need this info in files, or just in arrays in memory? How do you use the fiberassign_dates_*.txt files? Since the exposures table is obtained directly from the progress table, do you really want to read these files separately (i.e., to have the flexibility that they are non self consistent) or would it be better to just read progress.fits and derive the exposures table? Finally, your use of "dark" to include "gray" here is potentially confusing.

[forero]

Thanks, @dkirkby . This is useful.

Answering your questions.

Do you actually need this info in files, or just in arrays in memory? How do you use the fiberassign_dates_*.txt files?

Right now I read the files when I run fiberassign from quicksurvey.

do you really want to read these files separately (i.e., to have the flexibility that they are non self consistent) or would it be better to just read progress.fits and derive the exposures table?

I want to have the freedom to change fiberassign_dates independent from the exposures table. I want to have that flexibility to run fiberassign on different dates.

Finally, your use of "dark" to include "gray" here is potentially confusing.

I need to either include gray into bright or gray into dark because I am keeping separate quicksurvey runs for dark and bright. Right now I cannot fit into memory the whole set of targets.

I will replace some of the code to use functions in desisurvey. Then I will implement this in a function somewhere else. Where do you think it would be the best place for such a function? desisurvey, surveysim? desisim?

[forero]

I am closing this PR in the meantime.