Prototype frontpage for reorganised !MeqTree wiki
The MeqTree module is designed for implementing arbitrary mathematical expressions as one or more trees (graphs, really) of software "nodes". An important application is the calibration of an observing instrument for which a parametrized mathematical model is available. Calibration consists of solving for its parameters, usually by minimizing the difference between a set of measured data and their predicted values. The latter can be obtained by observing a known object (i.e. one for which a Source Model is available), and using the Instrument Model to calculate what the data should look like. The combination of a Source Model and an Instrumental Model is called a Measurement Equation. The page RadioAstronomyMeasurementEquations references papers that give a complete discussion of the physics behind the Measurement Equation. A more detailed introduction to the concepts behind MeqTrees is given on the MeqTreesIntroduction page.
Thus, the MeqTree module is designed for implementing arbitrary Measurement Equations, and solving for arbitrary subsets of their parameters. Since the state of every node in the tree can be monitored, inspected, and visualised, the user can see what is going on through an unusual number of windows. Although the MeqTree module was originally developed for the simulation and calibration of radio astronomy observations, it is completely "policy-free" and can be used for a wide range of other applications.
The purpose of this wiki is to encourage and support a worldwide community of MeqTree users and contributors. One way of measuring success in this endeavour is the extent to which this wiki is used and contributed to. Therefore, a ./HitParade page is maintained, and prizes are awarded regularly and publicly. In addition, there is a ./PictureGallery, a ./PublicationsGallery and a ./LevityExchange page.
Welcome
The ./AboutMeqTrees page gives some details about the project etc
The ./AboutThisWiki page spells out the (minimal) rules for contributing most effectively to this wiki.
Check the ./News page for recent developments (last entry: ....)
Please participate in the Ongoing Discussions about Ideas for further developments
How to
Some ./FrequentlyAskedQuestions are answered here.
The Reference Manual (RefMan) describes nodes, their behaviour and interactions. The RefMan/AvailableNodeClasses is a mini-manual in its own right.
The Tree Definition Language (TDL) may be used to generate node-trees (graphs, really).
Much will become clear by studying the Demo and Example pages
./RunningTDLScripts, with and without the MeqBrowser
./SystemIssues: information about getting (and keeping) a working MeqTrees system
The material used in the various MeqTree ./WorkShops is available
Lowering the Threshold
Description of some existing ./FrameWorks, their use and interfaces
Check the ./UserProjects for scripts to cannibalize for your own projects
Use the ./ModuleExchange to share plugin subtrees (e.g. Jones matrices)
Some Radio Astronomy background
GeneralisedSelfcal and the MajorCycle
The LocalSkyModel (LSM) and the GlobalSkyModel (GSM)
SourceExtraction from (residual) images or CLEAN components
SynthesisImaging and related issues
Using !MeqTrees for other applications
FloppyOptics (Floptics) and ImplicitMeasurementEquations