[Jprogramming] Jdb vs Spark

How does Jdb compare to Apache Spark? https://goo.gl/kTSpRt What are the advantages and disadvantages of both systems? Skip Skip Cave Cave Consulting LLC -- For information about J forums see http://www.jsoftware.com/forums.ht

Re: [Jprogramming] J strengths?

> On Nov 28, 2017, at 1:59 PM, Andrew Dabrowski wrote: > > I've come to feel that all programming languages are ugly compromises that > are about equally good/bad at solving practical problems, and the "best" > language is just the one you know the best. I think this is more true than false.

Re: [Jprogramming] J strengths?

Further on this comment Andrew, don’t get bogged down in the topic of tacit, you can get a lot of benefit form using J in native or explicit form and leave tacit for later. I have been programming in array languages for many years and also confess to being mesmerised by some of the tacit expres

Re: [Jprogramming] J strengths?

Another problem domain, I have done a lot of work in connectivity matrices (yes including transitive closure) in problem spaces such as; Minimum Path Credit Counterparty Limits in financial markets I did this in kdb (another descendant of APL) but the technique may be directly im

Re: [Jprogramming] J strengths?

While I have done, in the past, with APL*PlUS, (Yes, I am that old) more than I have done with J (interest rather than need  is now dominant), I find that the potential of J to deal with many things in a compact way is superior to that APL and any other languages which I have dealt with -from M

Re: [Jprogramming] PERT / graph operations

> On Nov 28, 2017, at 7:11 PM, Henry Rich wrote: > > You're right about the last bit - you can't start with a transitive closure. > I missed that. > > Suppose you turn each dependency into a J sentence, say > > a =: 5 > > or > > c =: longerof (a , b) > > or > > f =: a following (e , g)

Re: [Jprogramming] PERT / graph operations

Raul, > On Nov 28, 2017, at 5:32 PM, Raul Miller wrote: > > Something based on transitive closure does sound like the way to go. > > And this might be the essay Henry Rich was thinking of: > http://code.jsoftware.com/wiki/User:Roger_Hui/t > > But I am having trouble following along here. > >

Re: [Jprogramming] PERT / graph operations

You're right about the last bit - you can't start with a transitive closure.  I missed that. Suppose you turn each dependency into a J sentence, say a =: 5 or c =: longerof (a , b) or f =: a following (e , g) or combinations thereof.  There must be no loops in the dependencies, so you cou

Re: [Jprogramming] PERT / graph operations

Something based on transitive closure does sound like the way to go. And this might be the essay Henry Rich was thinking of: http://code.jsoftware.com/wiki/User:Roger_Hui/t But I am having trouble following along here. The text says "task C can only start after tasks A and B finish" and graph

Re: [Jprogramming] J strengths?

I guess we can disagree on whether the bogging down is to be attributed to J or to the user. Two-dimensional programming languages have been talked about for at least the 50 years I have been coding, and none has really taken off.  Just specifying such a language, never mind parsing it, would

Re: [Jprogramming] PERT / graph operations

There used to be an essay of Roger's called "Transitive closure" that discussed this in detail.  I can't find it now, but there seems to be a version of it hanging around at http://code.jsoftware.com/wiki/User:Roger_Hui/t .  Look for "Successor lists".  There are two versions, tcm and tcs, each

[Jprogramming] PERT / graph operations

I'm trying to code the "program evaluation and review technique" algorithm as an exercise in learning J. https://en.wikipedia.org/wiki/Program_evaluation_and_review_technique#Next_step.2C_creating_network_diagram_by_hand_or_by_using_diagram_software

Re: [Jprogramming] J strengths?

There's nothing specific to databases about the value of J. I've never done anything with databases before my current project.  I've used J to model the transformation pipeline of a graphics processor, the texture-mapping system of a flight simulator, a stock-trading program, a program to play

Re: [Jprogramming] J strengths?

Andrew Dabrowski: What topics of mathematics are you most interested in? -- For information about J forums see http://www.jsoftware.com/forums.htm

Re: [Jprogramming] J strengths?

Thanks.  I keep forgetting that J and its emulators are really popular for databases.  That's not something I deal with, so perhaps that's why I'm blind to some of its virtues. On 11/28/2017 04:21 PM, Henry Rich wrote: I use J for all my own work because I get results fast. Example: I am curr

Re: [Jprogramming] J strengths?

I use J for all my own work because I get results fast. Example: I am currently working on a database project, a big key/value store written as about 200KLOC of C++, and I proposed a major design change.  Management was supportive but concerned, so I offered to write a simulation of the system

[Jprogramming] J strengths?

As much as I've complained about J in these forums I've been having a good time translating some simple code into J.  Someone gave me wise advice, to stick with explicit definitions until I know the language well, which advice I have cordially ignored because I'm having too much fun playing cod

Re: [Jprogramming] Nullary function?

A lack of nothing?    >0$0$Unit could also possibly be the result of a function or a statement. /Erling On 2017-11-28 18:41, Devon McCormick wrote: ​A little late to the discussion, but I've thought that J's disallowing of niladic functions has the nice side-effect that simply entering a name

Re: [Jprogramming] Nullary function?

Unit could also possibly be the result of a function or a statement. /Erling On 2017-11-28 18:41, Devon McCormick wrote: ​A little late to the discussion, but I've thought that J's disallowing of niladic functions has the nice side-effect that simply entering a name with no arguments shows you t

Re: [Jprogramming] Nullary function?

​A little late to the discussion, but I've thought that J's disallowing of niladic functions has the nice side-effect that simply entering a name with no arguments shows you the definition.​ On Tue, Nov 28, 2017 at 12:12 PM, Andrew Dabrowski wrote: > Thanks! I think I'd seen that in Learning J

Re: [Jprogramming] Nullary function?

Thanks!  I think I'd seen that in Learning J but had forgotten about it. On 11/28/2017 08:27 AM, Brian Schott wrote: Yes, David Lambert's answer is good. In addition, instead of the RHA of '', using subsets of 0 1 2 3 gives nouns, adverbs,conjunctions, and verbs only. On Tue, Nov 28, 2017 at 8

Re: [Jprogramming] (no subject)

Building on the original definition: ".10#'1' 11 mmowa =: ".'x',~'1'#~[ mmowa 50 11 datatype mmowa 50 extended On Thu, Nov 23, 2017 at 3:43 AM, Raul Miller wrote: >F=: p.&10x@#&1"0 >F i.10 > 0 1 11 111 1

Re: [Jprogramming] Nullary function?

Yes, David Lambert's answer is good. In addition, instead of the RHA of '', using subsets of 0 1 2 3 gives nouns, adverbs,conjunctions, and verbs only. On Tue, Nov 28, 2017 at 8:11 AM, David Lambert wrote: > names_j_'' > names_z_'' > > > --

Re: [Jprogramming] Nullary function?

names_j_'' names_z_'' Date: Mon, 27 Nov 2017 12:33:26 -0500 From: Andrew Dabrowski To:programm...@jsoftware.com Subject: Re: [Jprogramming] Nullary function? Message-ID:<4ebaaa1a-5a50-8f5d-cbb5-d74d1ebcc...@indiana.edu> Content-Type: text/plain; charset=utf-8; format=flowed ... How can I learn