Feel little sorry for this question.For refine my answer here, I have done some dig about ArrayComponents.Then I found Internal`ToEquivalenceClass here today. Actually I meet it many time before this in those defined page. Maybe it cannot help to improve my solution.I have to say,it is maybe a more curious as m_goldberg blamed but not for some certain intention. I have recited almost all built-in function in Mathematica,I just want to find out some new thing to study.

And this comment hint the Internal`* function is useless for user(maybe just usefull developer).But as we know,such as Internal`AbsSquare,Internal`StringToDouble,Internal`ListMin or Internal`Bag or other things have a good exposure rate in MMA.SE.I think the SE is a place to discuss openly.If someon else also are interested in those undocumented function like me. we can dig and discuss it together. If it wast somebody's time,it not my intention indeed..

  • 1
    1._ I think there is plenty of precedent for discussing undocumented functions, I personally would welcome them in general terms. 2._ That particular question, seems to lack any meaningful motivation and is very unlikely to attract interest, therefore it does need work. 3._ In any case, however off-topic a question may be, it does not justify any kind of angry outburst, from anybody.
    – rhermans
    Commented Jul 10, 2017 at 15:30
  • 3
    I think most undocumented functions are going to be uninteresting, unknowable outside WRI, not worth explaining, and primarily for supporting other user-level functions. The few exceptions may seem like a lot, but they form a small proportion of all such functions. Further, the exceptions have tended to appear in answers, not in out-of-the-blue questions. The insipidness of picking arbitrarily a function to ask about should be flavored with some context suggesting its potential importance as a standalone function (= point 2._ of rhermans's comment & the 2nd para. of m_goldberg's answer).
    – Michael E2
    Commented Jul 10, 2017 at 23:37
  • One of my favorite used to be BoxForm`Intercalate. It has the same basic usage as Riffle. Commented Jul 15, 2017 at 2:05
  • 2
    @ChrisChiasson that was not an answer, consider: 805
    – Kuba Mod
    Commented Jul 17, 2017 at 7:55
  • @Kuba please explain why, in detail Commented Jul 17, 2017 at 14:09
  • 1
    @ChrisChiasson the question is: "Are questions about undocumented functions deprecated on Mathematica.SE?" better tell me how your example answers that. Isn't it exactly what is considered an answer in linked topic?
    – Kuba Mod
    Commented Jul 17, 2017 at 14:20
  • @Kuba what you put in direct quotation marks does not appear in yode's question, unless I am missing something. I read his question as: assuming it is within the rules for him to ask, what undocumented functions do we know about that we can share with him. Please show cause as to why my answer isn't an answer. Commented Jul 17, 2017 at 14:30
  • @ChrisChiasson the only question I see appears in a title, maybe should be repeated in the body I agree, nevertheless it is that vs your interpretation of the topic. Either is fine for me but yours and m_goldberg's answers answer different asspects and it can't be that both are the case. Since he was first and OP already responded, not claiming it is off topic answer, I suppose it is clear
    – Kuba Mod
    Commented Jul 17, 2017 at 14:35
  • @ChrisChiasson OP's invitation to dig and discuss seem (to me) to be an additional invitation for creating a chat/discussion group rather than a direct purpose of the question. Again, I may be wrong but the topic should be clear so we can wait for yode to clarify.
    – Kuba Mod
    Commented Jul 17, 2017 at 14:39
  • @Kuba, I think you were too quick with your moderation, regardless of the ultimate resolution Commented Jul 17, 2017 at 14:42
  • @ChrisChiasson Your answer was flagged as 'not an answer' by community members so it was not only mine impression. I will gladly revert my actions it they were too quick but the case is 'explicit question in the title' vs your interpretation. And yours answer validity makes the existing answer off topic. So I did what I did because it was a matter of facts not interpretation. Sorry if you felt I could have been more subtle, I will take that lesson.
    – Kuba Mod
    Commented Jul 17, 2017 at 14:52
  • @Kuba,Chris Chiasson I'm not a new user in SE.Actually I always confused why some question posted by me always unhappy for some people.Such as the recent two posts(one,two).Those is closed now,but I think they are useful post still.Since that post is closed now tagged with question is out of scope.It is relevant to the subject(undocument function).
    – yode
    Commented Jul 17, 2017 at 14:56
  • @Kuba, I think it should be reverted, if only because yode has yet to mark anything as an accepted answer. Turning my answer into a comment denies yode the opportunity to decide if my answer is acceptable. Lastly, I'd note that like yode, I'm hardly a new user or spam bot. Commented Jul 17, 2017 at 14:59
  • @yode, in the words of my generation: haters gonna hate ( urbandictionary.com/define.php?term=Haters%20Gonna%20Hate ) Commented Jul 17, 2017 at 15:01
  • 5
    I agree with @Kuba it's not an answer. It's not even about the website, which is the overall subject of Meta.
    – Michael E2
    Commented Jul 17, 2017 at 19:48

1 Answer 1


I don't think questions about undocumented functions should be deprecated categorically. Like any other questions, the quality of such questions should be judged and those found wanting rejected. In the case of the question being condsidered here, I don't think the quality of the question was very high.

Had you discussed in your question how you came across Internal`ToEquivalenceClass and how it relates to graph theory work, I would not have had such a hissy-fit. Had you asked the question well and, further, given a self-answer, I would have up-voted both the question and the answer.

Even now, I think it would have been better to bring the matter up in chat than to ask about it on main site.

  • I hope I have not offensed to you still. I just want to know how to ask a qualified question since you always think they're not very appropriate.
    – yode
    Commented Jul 9, 2017 at 16:26
  • @yode. Not offense taken. I have a fairly thick skin. I have revised my answer to give my opinion how to make such questions acceptable. Further, I do not always disapprove of your questions. I have up-voted quite a few of them.
    – m_goldberg
    Commented Jul 9, 2017 at 16:37
  • Anyway,thanks..:)
    – yode
    Commented Jul 9, 2017 at 16:41

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