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J Language – New Website

76 points by 4thaccount 8y ago

snazz 8y ago
I suggest they update the logo since it now looks very out of place. Does anyone use J for anything aside from experimentation (and math)? I know the same question is asked of everything that deviates from the mainstream, but the APL (and by extension J) world seems really far out from my mental model of computers.
- steve19 8y ago
  I struggle to understand why you would want to use it instead of array orientated languages like R, Julia, Matlab or Python/numpy. When is terseness a feature? It must make maintenance a nightmare.
  - ehaliewicz2 8y ago
    Takes this with a grain of salt, since I haven't done much more than dabble with J, but I've heard that it (and APL) basically forces you to carefully read and fully understand the code, rather than skimming, which is generally what happens with "easier to read" languages. And since it's so dense, you don't need a lot of lines of code to do most things.
  - scottlocklin 8y ago
    Those are only partially array oriented languages. I use J for most of my personal projects because it's terse and highly productive. From empty emacs buffer to something that works; 5x faster than developing from raw R, and I'm bad at J and decent at R. Of course if R has a package which does what I need, it's easier to use that. There's also the matter that for medium big data problems, J can do plenty that R will never be able to do. Terseness is a feature. It's also a good design in general, even though it breaks most people's brains.
    - 4thaccount 8y ago
      When you say that J is faster than R, are you referring to using Jd versus dealing with R's read_csv, or are you just talking about the calculations in general for the same size dataset and just using vanilla native language constructs?
      - tluyben2 8y ago
        Not OP but I think he is referring to speed of development, not execution?
        4thaccount 8y ago
        Thanks, that seems obvious now. I should not skim so much.
  - jonahx 8y ago
    All of the languages you mentioned are watered-down and inferior versions of the programming models invented by APL and J. By that I don't mean that APL/J are unilaterally better -- there are plenty of practical reasons to choose R/Matlab/numpy -- but they are unquestionably more beautiful and visionary. They hang together at a deep level in a way those languages do not. They are also much harder to learn, and much more fun. On the readability of APL (terrific video): https://www.youtube.com/watch?v=v7Mt0GYHU9A https://www.youtube.com/watch?v=v7Mt0GYHU9A Alan Perlis on its beauty: https://www.jsoftware.com/papers/perlis78.htm https://www.jsoftware.com/papers/perlis78.htm
- tluyben2 8y ago
  I write quite a lot in j/k ; unfortunately usually not for work related things but more and more so. I am far more productive in them than other languages for certain (mostly to do stocks and financials) fields. But I cannot expect my colleagues to go from C# to j ;)
bithavoc 8y ago
For a second I thought this was the return of J Sharp https://en.m.wikipedia.org/wiki/J_Sharp https://en.m.wikipedia.org/wiki/J_Sharp
aboutruby 8y ago
Seems to be a lightweight shell that links to their wiki: https://code.jsoftware.com/wiki/Jd/Overview https://code.jsoftware.com/wiki/Jd/Overview
- 4thaccount 8y ago
  Yea...sorry! I got excited and posted the link before realizing the majority of the site was still using the old wiki layout. Please forgive. I think the new landing page does look nicer and more modern.
snek 8y ago
why does no programming language website ever include an example of the language? just a hello world or whatever would go a huge way. this annoys me so much.
- ehaliewicz2 8y ago
  To be fair, most people probably wouldn't be able to read a serious example of J, and hello world is just 'hello, world', so I think it's ok.
  - snek 8y ago
    that just makes me more curious about what J looks like. and maybe a hello world isn't the best example for every language, but there should be some small example you can show.
    - kingaillas 8y ago
      I dug around and found Advent of Code 2015 solutions, in J: https://code.jsoftware.com/wiki/Essays/Advent_Of_Code https://code.jsoftware.com/wiki/Essays/Advent_Of_Code That should be plenty of examples for you.
- 4thaccount 8y ago
  In APL and J, hello world is just 'Hello, World' I think if I recall correctly. What makes the languages (APL, J, K) impressive is that you can simplify what is sometimes pages of code into a single line of symbols (APL) or standard ASCII characters (J and K). Keep in mind that these languages are the definition of line noise to most coders as having prior knowledge of things like C, Python...etc will do you zero good as the building blocks are completely different from a high level. They might have if-statements in the language, but they're hardly idiomatic. J emphasizes tacit programming which is kind of like a data flow model made up of function application. The languages are quite mathy in some ways, but still approachable. I find them to be lots of fun, very interactive, thought provoking, and pretty cool. I've only written a little APL & J, but enjoyed how I built my command up from a few built-in primitives. A problem to me involves reading other people's code which uses primitives I haven't learned yet, or common idioms (Ex: you can make your own average function with a few characters avg=.+/%# so no need to add it to the stdlib). The average function on the tryapl.org site looked a little funny to me...then I realized it worked for not only lists, but multi-dimemsional data structures of n dimensions like tables or lists of tables. I imagine it takes awhile to become proficient. Surprisingly, both J and APL have some decent support for things such as graphics, but they are still small communities compared to languages we know and love like Python. In short, give it a try. J has some built in documentation called "J labs" that is submitted by the community. Dyalog APL has a free version for non commercial use and the excellent tryapl.org. Try not to be turned off by the bizzare symbols in APL. They have a long history and are easy to enter with either the IDE or keyboard (especially if you buy one from Dyalog with the symbols on the keys). The inventor of APL got the Turing Award awhile back (later invented J). It was also a big IBM product back in the day and is still used by companies like Volvo.
asaph 8y ago
J Is free for non-commercial use under the GPL. What does a commercial license from jsoftware cost?
- 4thaccount 8y ago
  Jd the J database is free for non commercial use and listed as $600 for a single user to use commercially on their site somewhere last I looked. They have fancier enterprise support contracts as well. As for the language itself, it is free to use in commercial projects I think (someone please correct me if I'm wrong), but the source code to the J language is either GPL3 or you can pay. I think that means if you wanted to use the J source as part of a commercial project, you can pay or make the source available under the GPL3 license. I'm honestly not sure though and would appreciate some clarification.
haolez 8y ago
I like to play with algotrading bots and I'm really tempted to try out J or K in the near future. It has been in my backlog for a while :)
kyllo 8y ago
Have any data scientists here who were primarily working in R or Python, learned J? What did you think? I love programming languages that teach you new ways of thinking about programming and I'm very curious about the APL family--thinking of learning J or q/kdb+. I do most of my work in query languages on column-store databases, then some visualization and hypothesis testing on top. So I'm wondering if I could find J more expressive than R/Python + some SQL-like language.
- 4thaccount 8y ago
  I use Python a bunch and have used R in the past. I've dabbled in Julia and both APL & J. I know just enough to say that APL & J are much more expressive as long as Python doesn't have a fix_problem() method built-in. I believe ScottLocklin says something similar below, but he has a lot more experience in R and J than I. Now q/kdb+ might be expensive, but I can only dream of doing analysis using it. SQL is great, but having the full power of K And Q-SQL would be pretty awesome.
  - kyllo 8y ago
    Yeah it really seems to me like a highly expressive data analysis language with a tightly integrated column-store database system could have saved many, many millions of dollars and person-hours compared to Hadoop and Spark.
  - kd0amg 8y ago
    I know just enough to say that APL & J are much more expressive as long as Python doesn't have a fix_problem() method built-in. This is pretty much the same impression I got, though I came from the other direction. I was kind of surprised how many StackOverflow posts ask about adapting a fix_problem() method to fix some very_similar_problem.
    - 4thaccount 8y ago
      Yep. It's one reason why I prefer to write my own code where possible instead of using 3rd party libraries. When you need to change something, it is nice to not read tons of other code.
deleted 8y ago
[deleted]
jodrellblank 8y ago
NB. You can get J for Apple iOS, free: https://itunes.apple.com/us/app/j701/id1255235993 https://itunes.apple.com/us/app/j701/id1255235993 and it's apparently got a new in-app keyboard to make it easier, since last time I looked.
0db532a0 8y ago
Learn J here: https://www.jsoftware.com/help/learning/contents.htm https://www.jsoftware.com/help/learning/contents.htm
etatoby 8y ago
I've long been a big fan of APL, since I learned it many years ago. I started by studying on the classic book by Gilman and Rose and trying to use the scarce freeware/shareware implementations available at the time. At the time it was hard or impossible to get anything working for free on a Linux computer. Nowadays there is a great, free, and actively maintained implementation: GNU APL. That, combined with the widespread use of Unicode and the APL support in Linux/XOrg keyboard definitions, make it so much easier to get started than in the past. I have used APL mostly for fun, that is, for learning the language itself, solving mathematical puzzles, and taking part in "code golf" games. I find the language exquisite, especially its programming model based on multi-dimensional arrays, its graphical symbols, and its grammar. But it is somewhat "impractical" to use nowadays. J is a great successor (designed by the same mastermind behind APL) but I found it harder to learn (and to read) due to its ASCII "line-noise" look and to the prevalence of point-free or tacit function definitions, which I find inferior in readability. I'm only now learning NumPy and TensorFlow, and I bet their authors were inspired by APL. Does anybody have any benchmarks of J's performance against NumPy? As for K, I wouldn't recommend picking it up. It's closed-source and documentation-less, meaning good look if you run into any trouble; its error messages are notoriously infuriating; it overloads its operators with a ton of meanings, depending on context, even more so than APL and J; and its fundamental programming paradigm is not based on multi-dimensional arrays. On the other hand, writing an APL-like frontend for TensorFlow looks like a nice project!
- etatoby 8y ago
  Update: I ran a quick benchmark (large matrix multiplication) between GNU APL, J, and NumPy (standard pre-compiled linux amd64 packages, all running single-core.) Here are the results. GNU APL (1.7) ⍴+.×⌿?2 3000 3000⍴1e10 - size 3000: 65s, 9GiB RSS (crash on bigger sizes) J (8.07) $(+/ .*)/?2 3000 3000$1e10 - size 3000: 2s, 0.2GiB RSS - size 10000: 60s, 3.7GiB RSS (crash on bigger sizes) NumPy (1.13.3, blas/lapack 3.7.1) import numpy a=numpy.random.randint(0, 1e10, (2,3000,3000)) print((a[0,] @ a[1,]).shape) - size 3000: 25s, 0.2GiB RSS - size 10000: (>15m, I killed it) 2.3GiB RSS Conclusions: J's implementation is surprisingly performant! Easily beating NumPy on speed alone by a factor of 10 or more! (And I thought blas/lapack were already heavily optimized libraries!) J's memory usage is comparable to that of NumPy. GNU APL had the worst memory and cpu profile of them all.

76 points by 4thaccount 8y ago

I suggest they update the logo since it now looks very out of place. Does anyone use J for anything aside from experimentation (and math)? I know the same question is asked of everything that deviates from the mainstream, but the APL (and by extension J) world seems really far out from my mental model of computers.

steve19 8y ago
I struggle to understand why you would want to use it instead of array orientated languages like R, Julia, Matlab or Python/numpy. When is terseness a feature? It must make maintenance a nightmare.
- ehaliewicz2 8y ago
  Takes this with a grain of salt, since I haven't done much more than dabble with J, but I've heard that it (and APL) basically forces you to carefully read and fully understand the code, rather than skimming, which is generally what happens with "easier to read" languages. And since it's so dense, you don't need a lot of lines of code to do most things.
- scottlocklin 8y ago
  Those are only partially array oriented languages. I use J for most of my personal projects because it's terse and highly productive. From empty emacs buffer to something that works; 5x faster than developing from raw R, and I'm bad at J and decent at R. Of course if R has a package which does what I need, it's easier to use that. There's also the matter that for medium big data problems, J can do plenty that R will never be able to do. Terseness is a feature. It's also a good design in general, even though it breaks most people's brains.
  - 4thaccount 8y ago
    When you say that J is faster than R, are you referring to using Jd versus dealing with R's read_csv, or are you just talking about the calculations in general for the same size dataset and just using vanilla native language constructs?
    - tluyben2 8y ago
      Not OP but I think he is referring to speed of development, not execution?
      - 4thaccount 8y ago
        Thanks, that seems obvious now. I should not skim so much.
- jonahx 8y ago
  All of the languages you mentioned are watered-down and inferior versions of the programming models invented by APL and J. By that I don't mean that APL/J are unilaterally better -- there are plenty of practical reasons to choose R/Matlab/numpy -- but they are unquestionably more beautiful and visionary. They hang together at a deep level in a way those languages do not. They are also much harder to learn, and much more fun. On the readability of APL (terrific video): https://www.youtube.com/watch?v=v7Mt0GYHU9A https://www.youtube.com/watch?v=v7Mt0GYHU9A Alan Perlis on its beauty: https://www.jsoftware.com/papers/perlis78.htm https://www.jsoftware.com/papers/perlis78.htm
tluyben2 8y ago
I write quite a lot in j/k ; unfortunately usually not for work related things but more and more so. I am far more productive in them than other languages for certain (mostly to do stocks and financials) fields. But I cannot expect my colleagues to go from C# to j ;)

bithavoc 8y ago

For a second I thought this was the return of J Sharp https://en.m.wikipedia.org/wiki/J_Sharp https://en.m.wikipedia.org/wiki/J_Sharp

aboutruby 8y ago

Seems to be a lightweight shell that links to their wiki: https://code.jsoftware.com/wiki/Jd/Overview https://code.jsoftware.com/wiki/Jd/Overview

4thaccount 8y ago
Yea...sorry! I got excited and posted the link before realizing the majority of the site was still using the old wiki layout. Please forgive. I think the new landing page does look nicer and more modern.

snek 8y ago

why does no programming language website ever include an example of the language? just a hello world or whatever would go a huge way. this annoys me so much.

ehaliewicz2 8y ago
To be fair, most people probably wouldn't be able to read a serious example of J, and hello world is just 'hello, world', so I think it's ok.
- snek 8y ago
  that just makes me more curious about what J looks like. and maybe a hello world isn't the best example for every language, but there should be some small example you can show.
  - kingaillas 8y ago
    I dug around and found Advent of Code 2015 solutions, in J: https://code.jsoftware.com/wiki/Essays/Advent_Of_Code https://code.jsoftware.com/wiki/Essays/Advent_Of_Code That should be plenty of examples for you.
4thaccount 8y ago
In APL and J, hello world is just 'Hello, World' I think if I recall correctly. What makes the languages (APL, J, K) impressive is that you can simplify what is sometimes pages of code into a single line of symbols (APL) or standard ASCII characters (J and K). Keep in mind that these languages are the definition of line noise to most coders as having prior knowledge of things like C, Python...etc will do you zero good as the building blocks are completely different from a high level. They might have if-statements in the language, but they're hardly idiomatic. J emphasizes tacit programming which is kind of like a data flow model made up of function application. The languages are quite mathy in some ways, but still approachable. I find them to be lots of fun, very interactive, thought provoking, and pretty cool. I've only written a little APL & J, but enjoyed how I built my command up from a few built-in primitives. A problem to me involves reading other people's code which uses primitives I haven't learned yet, or common idioms (Ex: you can make your own average function with a few characters avg=.+/%# so no need to add it to the stdlib). The average function on the tryapl.org site looked a little funny to me...then I realized it worked for not only lists, but multi-dimemsional data structures of n dimensions like tables or lists of tables. I imagine it takes awhile to become proficient. Surprisingly, both J and APL have some decent support for things such as graphics, but they are still small communities compared to languages we know and love like Python. In short, give it a try. J has some built in documentation called "J labs" that is submitted by the community. Dyalog APL has a free version for non commercial use and the excellent tryapl.org. Try not to be turned off by the bizzare symbols in APL. They have a long history and are easy to enter with either the IDE or keyboard (especially if you buy one from Dyalog with the symbols on the keys). The inventor of APL got the Turing Award awhile back (later invented J). It was also a big IBM product back in the day and is still used by companies like Volvo.

asaph 8y ago

J Is free for non-commercial use under the GPL. What does a commercial license from jsoftware cost?

4thaccount 8y ago
Jd the J database is free for non commercial use and listed as $600 for a single user to use commercially on their site somewhere last I looked. They have fancier enterprise support contracts as well. As for the language itself, it is free to use in commercial projects I think (someone please correct me if I'm wrong), but the source code to the J language is either GPL3 or you can pay. I think that means if you wanted to use the J source as part of a commercial project, you can pay or make the source available under the GPL3 license. I'm honestly not sure though and would appreciate some clarification.

haolez 8y ago

I like to play with algotrading bots and I'm really tempted to try out J or K in the near future. It has been in my backlog for a while :)

kyllo 8y ago

Have any data scientists here who were primarily working in R or Python, learned J? What did you think? I love programming languages that teach you new ways of thinking about programming and I'm very curious about the APL family--thinking of learning J or q/kdb+. I do most of my work in query languages on column-store databases, then some visualization and hypothesis testing on top. So I'm wondering if I could find J more expressive than R/Python + some SQL-like language.

4thaccount 8y ago
I use Python a bunch and have used R in the past. I've dabbled in Julia and both APL & J. I know just enough to say that APL & J are much more expressive as long as Python doesn't have a fix_problem() method built-in. I believe ScottLocklin says something similar below, but he has a lot more experience in R and J than I. Now q/kdb+ might be expensive, but I can only dream of doing analysis using it. SQL is great, but having the full power of K And Q-SQL would be pretty awesome.
- kyllo 8y ago
  Yeah it really seems to me like a highly expressive data analysis language with a tightly integrated column-store database system could have saved many, many millions of dollars and person-hours compared to Hadoop and Spark.
- kd0amg 8y ago
  I know just enough to say that APL & J are much more expressive as long as Python doesn't have a fix_problem() method built-in. This is pretty much the same impression I got, though I came from the other direction. I was kind of surprised how many StackOverflow posts ask about adapting a fix_problem() method to fix some very_similar_problem.
  - 4thaccount 8y ago
    Yep. It's one reason why I prefer to write my own code where possible instead of using 3rd party libraries. When you need to change something, it is nice to not read tons of other code.

deleted 8y ago

[deleted]

jodrellblank 8y ago

NB. You can get J for Apple iOS, free: https://itunes.apple.com/us/app/j701/id1255235993 https://itunes.apple.com/us/app/j701/id1255235993 and it's apparently got a new in-app keyboard to make it easier, since last time I looked.

0db532a0 8y ago

Learn J here: https://www.jsoftware.com/help/learning/contents.htm https://www.jsoftware.com/help/learning/contents.htm

etatoby 8y ago

I've long been a big fan of APL, since I learned it many years ago. I started by studying on the classic book by Gilman and Rose and trying to use the scarce freeware/shareware implementations available at the time. At the time it was hard or impossible to get anything working for free on a Linux computer. Nowadays there is a great, free, and actively maintained implementation: GNU APL. That, combined with the widespread use of Unicode and the APL support in Linux/XOrg keyboard definitions, make it so much easier to get started than in the past. I have used APL mostly for fun, that is, for learning the language itself, solving mathematical puzzles, and taking part in "code golf" games. I find the language exquisite, especially its programming model based on multi-dimensional arrays, its graphical symbols, and its grammar. But it is somewhat "impractical" to use nowadays. J is a great successor (designed by the same mastermind behind APL) but I found it harder to learn (and to read) due to its ASCII "line-noise" look and to the prevalence of point-free or tacit function definitions, which I find inferior in readability. I'm only now learning NumPy and TensorFlow, and I bet their authors were inspired by APL. Does anybody have any benchmarks of J's performance against NumPy? As for K, I wouldn't recommend picking it up. It's closed-source and documentation-less, meaning good look if you run into any trouble; its error messages are notoriously infuriating; it overloads its operators with a ton of meanings, depending on context, even more so than APL and J; and its fundamental programming paradigm is not based on multi-dimensional arrays. On the other hand, writing an APL-like frontend for TensorFlow looks like a nice project!

etatoby 8y ago
Update: I ran a quick benchmark (large matrix multiplication) between GNU APL, J, and NumPy (standard pre-compiled linux amd64 packages, all running single-core.) Here are the results. GNU APL (1.7) ⍴+.×⌿?2 3000 3000⍴1e10 - size 3000: 65s, 9GiB RSS (crash on bigger sizes) J (8.07) $(+/ .*)/?2 3000 3000$1e10 - size 3000: 2s, 0.2GiB RSS - size 10000: 60s, 3.7GiB RSS (crash on bigger sizes) NumPy (1.13.3, blas/lapack 3.7.1) import numpy a=numpy.random.randint(0, 1e10, (2,3000,3000)) print((a[0,] @ a[1,]).shape) - size 3000: 25s, 0.2GiB RSS - size 10000: (>15m, I killed it) 2.3GiB RSS Conclusions: J's implementation is surprisingly performant! Easily beating NumPy on speed alone by a factor of 10 or more! (And I thought blas/lapack were already heavily optimized libraries!) J's memory usage is comparable to that of NumPy. GNU APL had the worst memory and cpu profile of them all.