4 April 2005 To: Crystal Brogan , Carlos De Breuck , James Di Francesco , Debra Shepherd , Rein H. Warmels , Martin Zwaan , Munetake Momose Andrew Baker From: Debra Shepherd ALMA Offline Subsystem Scientist The ALMA offline interferometer+single dish imaging test preparation is continuing with extensive testing in-house to improve the way the software handles the combination of single dish images and interferometric uv data. We expect the test will be able to start in early April and I will let you know in a few weeks exactly when we will be ready to start. Just to let you know what is going on and what to expect, I want to give you some background on the test scope, datasets, and let you know how to proceed once the software is released. ---------------- I want to thank you first and foremost for agreeing to take the time to test the AIPS++ software for this first ALMA Offline subsystem test. This test is important for several reasons: 1. Issues identified during the tests will help drive software priorities to develop functionality for ALMA offline data reduction and imaging. 2. This test will grade the science software requirements to determine if the mosaic software meets the functional needs for ALMA. 3. Scripts generated during the testing will continue to be used during automated regression testing and will provide valuable insight to the pipeline heuristics team who will use the detailed processing steps and parameter inputs to develop automated pipeline decision trees. Two mosaic datasets have been chosen which will be processed through AIPS++: - A 3 mm spectral line Berkeley-Illinois-Maryland Array (BIMA) mosaic project that observed 12CO(1-0) line emission in the galaxy NGC 4826. The single dish image was created using on-the-fly (OTF) mapping with the 12m antenna near Tucson, AZ. The BIMA mosaic was reduced and imaged during the last ALMA User Test. - A 3.6 cm Very Large Array (VLA) mosaic project that observed continuum emission from ionized gas in the Orion Nebula. The single dish image was created from an OTF map made with the Green Bank Telescope (GBT). The BIMA data represents low S/N data that may be appropriate for ALMA sub-millimeter observations while the VLA data represents higher S/N data with a large number of baselines that should have similar processing steps to ALMA millimeter observations. The AIPS++ software is in an active stage of development. As you are aware, the current infrastructure, GUIs, and scripting language (all Glish-based) will be replaced, leading to a change in the overall user interface. A prototype framework is being built and evaluated but is not ready to test at this time. Thus, this test will focus only on testing the underlying functionality of the C++ code to determine if it is adequate to meet the needs of ALMA. The test will use Glish scripting to combine the interferometric and single dish data in two ways and compare the results. Testers will be provided with *reduced* interferometric source uv-data and a final mosaic image and *reduced* single dish images. The combination methods will be: - image "feathering" where two images are "feathered" together in the Fourier plane in an optimal way. Low spatial frequencies of the mosaic interferometer are downweighted to ensure that the final image retains the resolution of the interferometric image. - joint deconvolution in which the single dish image is converted to uv data and gridded together with the raw uv interferometric data and then jointly deconvolved with, e.g., CLEAN, Multi-scale CLEAN, and/or MEM. GUIs will only be used when the user must interact with the software (e.g. interactively defining deconvolution regions, viewing the final image and obtaining statistics). Development of the existing Glish-based GUIs that are not essential to the data reduction paths in this test has been discontinued while priorities changed to support the framework conversion and added functionality required for millimeter data reduction. The documentation (both cookbook and on-line reference manual) should be adequate for you to figure out how to proceed with the test (this assumes knowledge of radio interferometry techniques but does not assume experience with single dish + interferometry combinations techniques). Comments on the cookbook and other documentation are welcome. As with the previous test, we will provide detailed descriptions of the data (e.g. correlator setup, window placement, etc...) to make it easier for you to test the software imaging capabilities. Because the scripting language and GUIs will be changed over the next year, this test will NOT evaluate the usability of script language or the GUI interface. User interface elements will be tested in 2005. Essentially, if you can do what is necessary to calibrate the data and get a scientifically accurate image (even if the syntax or process is a bit complicated), then this will be considered a successful test. It is expected that this test will take roughly 40 hours or less of your time. The test should begin in early April 2005 and will end one month later in early May 2005. During this month, the AIPS++ software developers and I will be available to help you with questions or problems that you may come across. Please do not start the test at the last minute! Be aware that although extensive testing of the software has been done in-house, software bugs may still exist. The developers will do their best to help you through any difficulties, including fixing any bugs and distributing new software if necessary. But they can only provide this support if they are given adequate time. If you find you cannot complete the test by the deadline, please contact me as soon as possible (dshepher@nrao.edu, work phone: 1-505-835-7398). During your testing, PLEASE keep a detailed script of the processing steps you do and your parameter inputs. Example scripts for both VLA and millimeter processing will be provided with the Cookbook. You can use these scripts to guide your reduction and minimize typing (you will just have to change inputs and then cut and paste commands into the Glish command line window). Detailed testing scripts are important for several reasons: 1. If you have a problem, you can send your script to the AIPS++ software developers and they will be able to help you figure out if the problem is with a typo in the script or if you have uncovered a real problem. 2. Test scripts will be reviewed and given to the pipeline heuristics team. Your processing decisions are based on years of experience and how you set parameters at each stage in the reduction process will provide valuable insight into how to best process millimeter data. This information will help establish the heuristics to automatically process ALMA data. When you complete your testing, please fill out the questionnaire provided to you describing your testing experience and any problems you encountered. Also, please examine the the list of requirements that are being evaluated during the processing. Provide grades for all requirements that you were able to exercise. All testing reports and requirements evaluations will then be used to write a final report which will be submitted to ALMA management and the AIPS++ development team. Thank you again for your valuable time! As soon as the software is ready to test, Joe McMullin will send you detailed information about where to download the latest AIPS++ software and installation instructions, along with information about where to download the cookbook, example scripts, and contact information. The data you will be testing will be burned onto a DVD and shipped to you before the test. Please select the data to test based on the list below: Data: Testers: ------------------------- --------------------------------- NGC 4826, CO galaxy, BIMA Carlos De Breuck James Di Francesco Andrew Baker Munetake Momose Orion, 3.6 cm continuum, VLA Martin Zwaan Rein H. Warmels Crystal Brogan VLA, BIMA, & PdBI data from Debra Shepherd TST1 and TST1.1 (regression testing) If you have any questions, issues, problems, please don't hesitate to contact me. Sincerely, Debra Shepherd National Radio Astronomy Observatory Subsystem Scientist for the ALMA Offline software e-mail: dshepher@nrao.edu work phone: 1-505-835-7398 FAX: 1-505-835-7027 home phone: 1-505-838-4014 ALMA Offline test page: currently under construction http://projectoffice.aips2.nrao.edu/almatst3/ALMA_TST2.0.html