[DISCONTINUED] Wish-list for MATLAB Answer sections.
Walter Roberson
on 8 Feb 2011
Latest activity Reply by Walter Roberson
on 12 Feb 2023
This topic (which was not started by Mathworks) is for features you would like to see for this MATLAB Answers facility.
I suggest one wish per answer, so that people can vote for individual wishes.
What should you post where?
Next Gen threads (#1): features that would break compatibility with previous versions, but would be nice to have
@anyone posting a new thread when the last one gets too large (about 50 answers seems a reasonable limit per thread), please update this list in all last threads. (if you don't have editing privileges, just post a comment asking someone to do the edit)
578 Comments
This particular Question is for discussion changes to the MATLAB Answers software itself -- the forum software that allows people to ask questions and make responses.
You should have created a new Question for that topic.
estimate the current height change along the course between point A=(sqrt3/2,1/2) and B=(1/2,sqrt3/2) identitfy 2 ways to estimate this height change one with derivatives one without
power = 2;
f = @(x, y) x .* y.^power;
A = [sqrt(3)/2, 1/2];
B = [1/2, sqrt(3)/2];
t = linspace(0, 1, 1000);
x = (1 - t) * A(1) + t * B(1);
y = (1 - t) * A(2) + t * B(2);
z = f(x, y);
height_change = z(end) - z(1);
disp(height_change);
this gave the answer of 0.1585 but it doesnt seem correct if i change the ^ to * the answer becomes 0 am i correctly computing what the question is asking
Dark theme/mode?
that already exists for MATLAB Answers. Go to the top right of any code block in MATLAB Answers, and click on the half filled circle, and you will toggle dark mode.
%example code block
Reminder: this Question is about the MATLAB Answers facility (this forum), with the MATLAB product wishlists being in other Questions.
Users need acces to eig function
Lapack is called in most circumstances where it makes sense to do so. Generally speaking, MATLAB delegates most vector and array mathematical operations to high-speed multithreaded libraries provided that the amount of work to be done is large enough to make it worth going through the interface code.
Yes, but why do you ask? Is there a particular reason you need or want to know what the internal implementation is doing? Why do you care as long as you receive the right answer?
Thank you Walter and Steven for providing valuable comments on this topic, precisely for what Walter said I decided to mention this as a wish in the wish-list and not as a question.
Do you know of any other kind of funstions in Matlab that migh be calling LAPACK or other libraries outside Matlab?
Thank you again
This is not going to happen, for performance reasons. If I scan the eigs code correctly, the circumstances under which eig is invoked would be cases where eig would need to use the qz algorithm, which it does by calling lapack. There is no hidden matlab-language source code for eig, to be stepped through.
I am specially interested in accesing the imaginary part of the eigensolution. However, when using eig, I can not "step in (F11)" into eig.m
For this reason I implemented a QR-based eigensolver in which it is possible for me to acces the information. But I think, it would be nice that eig.m could be executed line by line, just like eigs.m for instance. That way, the user can have more control on the flow of the information
https://www.mathworks.com/matlabcentral/fileexchange/16777-lapack provides an interface to call lapack directly
http://www.netlib.org/utk/people/JackDongarra/etemplates/node282.html
What "partial results" are you interested in observing? Note that if you have a particular algorithm in mind for computing eigenvalues and eigenvectors that takes a certain series of steps, the eig function's code may not use that same algorithm and may not need to compute those same intermediary results.
Since this isn't related to MATLAB Answers but to MATLAB in general you might want to ask it as a separate question and/or send an enhancement request for eig to return the additional information you seek to Technical Support. If you submit an enhancement request to Support a description of how you plan to use this information if it becomes available would be useful to provide some context for the request.
If you want to test that the eig function returns correct answers, on the other hand, you could always write your own tests. We have thorough testing for the eig function but I can certainly understand the "trust but verify" mindset.
If you open eigs.m, you will see it calls eig.m in lines 1026:1038, now, if for any reason you need to verify what eig., does, you can not, probably Matlab is calling LAPACK to solve eigenvalue problems with eig.m
But as a user, it would be nice if I can verify partial results during the calculation of eigenvalues and eigenvectors.
In my particular case, I needed eigenvalues, but also additional information handle by the eigensolver that was not available with matlab.
Could you expand on this?
Option to bookmark an answer or the whole question thread. And this should be available to us in the profile dashboard. I bookmark the page right now. Thanks for this thread too!
I often also store question and the accpeted answer in my MATLAB code library. I save them with a CodLib_typeOfAction filename format so I know what is in there. So CodLib_Extraction would be a live script with several sections , each with extraction example and with my comments. I was initially weak with extraction in MATLAB but now I am good with it. I run it and test these Q&As before saving so in future its good to go. Plus it helps me breakdown the problem statement and understand better.
Browser Bookmarks are normally when I find new functions. or an unique problem type.
Have not used Trello yet. Will check it out! thanks. I also think spell check for these answer boxes will be great!
There's lots of way to use trello. I use it as a project management tool and as a means of collect ideas.
What is Trello? (Link?) I don't use Chrome as my preferred browser because Chrome and Edge won't let you pin your heirarchical bookmarks panel to the left side of the screen like Firefox will. That's a deal breaker for me.
I used to use Chrome's bookmark tool so I could nest URLs by topic in subfolders. For example. Matlab > Plots, Matlab > fitting, etc.
But after accumulating may bookmarks over the years, I switched to using a Trello board which gives even more options for organization.
I'm sure you're aware of these options already. I think they are better than an internal bookmark system. I wonder if access to those internally stored bookmarks would still be available if a user ever stopped their subscription.
The ability for editors/moderators to split and combine threads.
- A comment is actually an answer, so being able to change it to being an answer
- The OP replies to a question by creating an answer, so being able to change an answer to a comment of the selected thread.
This was the highest rated request during a recent internal process.
For easy navigation and for the historians,
Anyone with edit privileges should feel free to update this whenever needed.
Well, after the last update of Matlab Answers my biggest wish is now to put the white space back between the answers! I don't know if this was a common request to get rid of it, but it looks dreadful with answers just all running into each other. I like white space in my code and I like it in an answers forum for the same reasons. It's unreadable without. Distinct answers should be properly delineated, rather than just a thin box around them all slammed together.
I don't like that copy-pasting a user's handle only copies the text rather than copying it as a link. Additionally, when you paste the handle, it adds a line break prior to the text (try copy-pasting any user handle here).
What I'd really like to see is a spellcheck option. I realize variable names would often be detected as misspellings but that would serve as an additional reminder to format code (which would then be ignored by the spell checker).
As far as I can see, Activity Feed / Manage Followed Content apparently only shows threads that I follow if there is a post to that thread after I follow it. That is, if I follow a thread but no one later posts to it, the thread does not show up in my Followed Content list.
I'd like to have all of my followed threads show up in that list, even if there has been no further activity. This is because I might want to post a suggestion or partial answer later, if the question remains unanswered.
Alternatively, could there be a way to filter by Unanswered+Followed?
(Answers Dev) I will forward your message on to the appropriate developer.
Do we have to have the 'This website uses cookies...' message at the bottom of the Matlab Answers website every single day when we navigate to the page? I know the internet is now festooned with these kinds of messages, but it's not as though this one is giving options to select, it is just information. I've been signed into my account the whole time - I know nothing about website design, but can it not realise that if you are logged in you have already seen the message?!
Is it worth to elaborate an old answer that's been accepted? Will anybody ever read it?
 
Wish:   A symbol to the left of the question, which indicates whether the question is on a "watch-list".
Problem: Many users do not understand how to use the markup button, {}Code, which results in formatting of text like the example below
.
if true
Error using assignin Unknown command option.
Error in cssm_c (line 20) assignin( 'base' , col_names(i) , num(:,i) );
end
.
Proposal: "{}Code" shall check whether any lines are selected and if not issue a warning. Or something better.
I used to do that for images until I learned that it behaves differently if you do that (put in angle brackets yourself) than if you use the image icon. Using the image icon will download the image to MATLAB Central and be permanently available, while if you do the HTML yourself, it points to the third party web site, which means the image may not be there forever.
I still use angle brackets for links because that acts the same way and it's faster.
Personally I type in all markup manually, except for doing block {} or (rarely) using the new paperclip.
What I would use would be a button that put spaces around operators and spaces after commas and semi-colons. SO that the result would flow nicely when auto-formatted. I have wasted so much time copying Maple non-spaced expressions and carefully going through them adding spacing so that they become readable.
My typical workflow is
- copy&paste code
- select code
- push {}Code
- and a little bit of fixing
I never see
if true
% code
end
Funny thing is that I don't use the buttons, B , I , and Aa in the same way, i.e. select followed by push. From now on I will use these buttons more.
I have the impression that some posters who try to markup correctly fail because they misunderstand the use of the button, {}Code.
Yeah, I think it assumes if you type that without already pasting in your code that you're just going to start hand typing your code it, which is almost never the case. Even if it were the case, posters leave the if true in there and it's just a mess, with bad indenting and often chunks of the code not formatted properly.
I agree. Perhaps something similar to add a link/picture/attachment. A popup box drops down where one can paste or write the Code and insert into the main text. if text in the main box is highlighted convert highlighted text into code.
*A modest wish:*
- The tag "oop" should qualify the post for the Category: Object Oriented Programming.
New list has been created! http://www.mathworks.com/matlabcentral/answers/42413-wish-list-2-and-bug-reports-for-matlab-answers-itself
The time-stamps for the activities log and the flagged content log appear to be in GMT. This is inconsistent with the other time-stamps that the user sees and so can lead to some confusion.
Not a major problem ;-)
I have been thinking myself that we should start a volume 2. I would not delete anything here, though.
Ideally some of what is here should be moved to the new list. I did not want to just go ahead and create the new Answers, though, as that would not give proper credit to the people who originally proposed them.
I like Daniel's Idea about leaving this alone and starting a wish-list 2.0. I can't even load this whole page without IE8 dumping. Thus any new wishes from today I can't see. Here's my first:
-Once you hit a reputation of say 20, get rid of the "how to post an answer" comments that take up space.
Now that so many of the wishes have been implemented (thank you to TMW), should we deleted the implemented answers to make it easier to find the outstanding issues? Should we refer to the current version of answers as 2.0 and start a new wish-list for it?
The new layout is a brute waste of space. The information density is sometimes lower than 3 sentences per screen.
The new boxes around everything confuse my eyes.
As of today, the new layout is wider! :)
Answers list in My Answers is sorted by old-to-new. It takes long time to go through the all answers and reach the latest one.
Please let me know if any sorting option exist to sort the Question list or Answer list. I have not found any such option ?
This regression should be fixed now.
We're aware of this regression (which somehow we manage to introduce seasonally...), and will get a fix out ASAP
Yes, TAB, I can confirm this. And it takes ages to find a list of my last ten answers. It is necessary to let the users select a sorting order and to allow a faster navigation as a popup to move 2, 4, 8, 16 pages to front or back. I hestitate to vote this question, because it cannot be found afterwards anymore in this giantic thread.
Actually I am talking about the list which shows my all the answers. Please see here
The oldest answered thread is on the top.
When I edit the Question at http://www.mathworks.com/matlabcentral/answers/42190-multiple-y-axis to reformat it, and Save, then the Save button flashes to Saving... and then reverts back to Save without the changes being saved.
Is a minimal title length of 4 words useful?
Yes, that worked. Perhaps it was the title length that was the problem.
When you have a chance could you try your edit again and see if it works? Thanks!
I was not changing the title, just the body.
Were you changing the title as well as the body of the question? We introduced a requirement that titles contain at least four "words" (whitespace-separated strings). It's possible that this validation was failing and the error message was not showing up. I'll look into it.
This Question is now so slow to load that Firefox and Safari now time-out the javascript 3 to 6 times for me.
We're aware of this issue and are investigating it.
Before today's changes, if one was editing and one highlighted text and clicked on the Code button, then after the operation was done, the selection was removed.
As of today's changes, the selection goes away for a small number of seconds while the reformat is done, but then the selection color comes back, highlighting a wider but shorter area, not covering all of the height of the original selection but covering wider (possibly even some areas that have no input.)
I noticed another weird thing about Answers. Not sure how to classify it. Maybe it's a bug, or just an unexpected/unwanted feature. <http://i46.tinypic.com/qs4dpt.jpg>
If you're creating an posting and switch to the "Preview" panel and double click a word there to highlight it, and then click some of the icons, like Bold or Italic, unpredictable things happen back in the test editor panel(not the Preview panel). Sometimes it will italicize the entire preview panel(not just the highlighted word), sometimes it inserts "_ITALICTEXT_" at random locations in the edit panel, or it might append "_BOLDTEXT_" to the text in the edit panel, sometimes it puts stars around all the text in both the edit panel and the Preview panel (but the text doesn't appear as bold though). It doesn't seem predictable. Granted, it's not something one should normally do, but I just thought I'd note it in case anyone ever decided to make some improvements to this forum, and it was easy to "fix".
Pages seem to be taking longer to load. This page especially.
With the more complicated scripts running the pages, the Answer box or the Comment box might not yet have had their style-sheet javascript loaded, so they can appear as fairly small input boxes with no controls, until (possibly minutes later) the js loading catches up and re-boxes everything.
Yes, that's what I'm using. And after the June 27 updates, more funny things started happening. Like the comment box is not as wide and then if you widen it, you can't click to place the cursor in a spot that is past a certain width. However that seems to come and go - it's not permanent. Most annoyingly, the vertical scroll bar only seems to function in the upper 75% of it's range. Clicking in the bottom 25% of the scroll bar, on the thumb bar, or on the little down arrow at the bottom of the scroll bar seem to not function at all for me. Luckily the mouse wheel still works down there so I can use that to scroll.
I confirm the funny behavior on FireFox, Win7.
To illustrate, type this in into the edit panel: word1 word2 word3. Now double click word2 in the Preview panel, not the edit panel. Now click the B or the I icon. What do you see? Why do you see any difference at all? Try it several times using B and I icons on various words. Does the text appear in the same place all the time or where you'd expect it (No). It might add BOLD TEXT after the word 3 while other times it will act on word 2 like it should, or even insert BOLD TEXT in between word2 and word 3 instead of appending it after word3 like it did at first.
In my experience, if one clicks on the Bold or Italic button when one does not have anything in the input area selected, then the _ITALICTEXT_ or *BOLDTEXT* is inserted.
Bold text is only bolded if it is within the same paragraph (and then only if there is whitespace before the first asterisk and after the last asterisk), so if you happen to have an empty line selected when you click on the bold icon, the * will be inserted but nothing will be bolded in the output.
Hey everyone, I propose that there should be a built in way to add attachments such as images. I think it would be beneficial when code is attached (such as providing the formula, expected plot to be generated etc.)
Attached code is less useful than embedded code.
This is effectively the same as http://www.mathworks.com/matlabcentral/answers/994-wish-list-for-matlab-answer-sections#answer_1953
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