Founder - New York City J Users Group
Email: <<MailTo(devon AT SPAMFREE acm DOT org)>>
J Wiki Pages
Following are largely ones I've written but also includes those related to areas in which I'm interested.
o An attempt at a minimal subset of J to ease the shock of learning all that there is.
o An example of using J for beginning financial data analysis.
o OLEExcel - manipulate Excel worksheets using OLE interface: Scripts/OLEExcel
o WS - save J variables to file and retrieve them: Scripts/File J Variables
o An early (unsuccessful) attempt to use the J database "JDB" on the "Netflix Challenge" data. It appears to have been unsuccessful because this dataset was too large for JDB to handle.
o Start of an attempt to detail J equivalents of basic operations in Microsoft Excel.
o An essay contrasting visual understanding with symbolic understanding.
o BigFiles - work with files larger than 2 GB: Scripts/Working with Big Files. This is now largely obsolete with the advent of 64-bit versions of J that have extended the scope of the file primitives to handle larger files.
o Some general limitations to consider when parallelizing code.
o Simple example of writing parallel code in J.
o Detailed example of how to simply parallelize code in J. This assumes the (common) sort of problem where coordination of the various parallel processes can be handled at the point where a "master" process spins them off and that the problem domain lends itself to "coarse" parallelism. I currently run two multi-core J routines almost every day using this technique and it's worked well for years now with substantial speed-ups and little difficulty.
o Complete examples of parallel J code presented at the APL2010 conference in Berlin, Germany, in September, 2010. These are the two examples of parallel code tasks, mentioned above, as well as an implementation of mutex (mutual exclusion), all written in J (version 6.02).
o Ideas on constructing arbitrarily-large datasets for comparing the effectiveness of different parallel implementations.
o "Red or Black" game simulation -> parallelization example NYCJUG/2011-04-12/RedOrBlackGameSimulation
Presentations About J
Feel free to take anything from these for your own presentation.
o "J: the Hard Parts" - a fairly lengthy talk explaining some of the parts of J that most people find the most difficult to comprehend, given to the N-Languages Meetup group on January 21, 2014.
o Presentation of J to a "Functional Programmers" Meetup group on September 20, 2011.
o "Short is Sweet" - An exposition on the importance of succinct expression (from a talk for the Kdb User Group on 12/9/2009).
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