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Walter Roberson

[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?
Wishlist threads (#1 #2 #3 #4 #5 #6): bugs and feature requests for Matlab Answers
Frustation threads (#1 #2): frustations about usage and capabilities of Matlab itself
Missing feature threads (#1 #2): features that you whish Matlab would have had
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)
Walter Roberson
Walter Roberson on 12 Feb 2023
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.
Joshua Thompson
Joshua Thompson on 12 Feb 2023
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
Juan Navarro
Juan Navarro on 12 Jul 2021
Dark theme/mode?
Walter Roberson
Walter Roberson on 12 Jul 2021
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.
Juan Navarro
Juan Navarro on 10 Jul 2021
Users need acces to eig function
Walter Roberson
Walter Roberson on 12 Jul 2021
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.
Steven Lord
Steven Lord on 12 Jul 2021
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?
Juan Navarro
Juan Navarro on 12 Jul 2021
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
Walter Roberson
Walter Roberson on 12 Jul 2021
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.
Juan Navarro
Juan Navarro on 12 Jul 2021
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
Walter Roberson
Walter Roberson on 12 Jul 2021
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
Steven Lord
Steven Lord on 12 Jul 2021
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.
Juan Navarro
Juan Navarro on 12 Jul 2021
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.
Walter Roberson
Walter Roberson on 10 Jul 2021
Could you expand on this?
klb
klb on 5 Feb 2021
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!
Adam Danz
Adam Danz on 6 Feb 2021
> I also think spell check for these answer boxes will be great!
I here that [sic]! 😃
My brain doesn't detect my own typos until I re-read my comments the next day.
It's on the wish list : see here.
klb
klb on 6 Feb 2021
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!
Adam Danz
Adam Danz on 6 Feb 2021
There's lots of way to use trello. I use it as a project management tool and as a means of collect ideas.
Image Analyst
Image Analyst on 6 Feb 2021
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.
Adam Danz
Adam Danz on 5 Feb 2021
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.
Cris LaPierre
Cris LaPierre on 18 Dec 2020
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.
Walter Roberson
Walter Roberson on 18 Dec 2020
This was the highest rated request during a recent internal process.
Adam Danz
Adam Danz on 18 Dec 2020
Adam Danz
Adam Danz on 25 Feb 2020
For easy navigation and for the historians,
Anyone with edit privileges should feel free to update this whenever needed.
Adam
Adam on 22 Jan 2020
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.
Adam Danz
Adam Danz on 22 Jan 2020
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).
Jeff Miller
Jeff Miller on 14 Mar 2019
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?
Rena Berman
Rena Berman on 15 Mar 2019
(Answers Dev) I will forward your message on to the appropriate developer.
Adam
Adam on 14 Mar 2019
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?!
Adam
Adam on 14 Mar 2019
Good to know, thanks!
David
David on 14 Mar 2019
No you should not be seeing this message each time you visit Answers, it's a bug we are working to fix in the next update in April. There are legal reasons for showing the cookie message but should only see it once.
- David
per isakson
per isakson on 24 Sep 2014
Is it worth to elaborate an old answer that's been accepted? Will anybody ever read it?
&nbsp
Wish: &nbsp A symbol to the left of the question, which indicates whether the question is on a "watch-list".
per isakson
per isakson on 11 Apr 2014
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.
Image Analyst
Image Analyst on 12 Apr 2014
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.
Walter Roberson
Walter Roberson on 12 Apr 2014
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.
per isakson
per isakson on 12 Apr 2014
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.
per isakson
per isakson on 11 Apr 2014
I have the impression that some posters who try to markup correctly fail because they misunderstand the use of the button, {}Code.
Image Analyst
Image Analyst on 11 Apr 2014
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.
Joseph Cheng
Joseph Cheng on 11 Apr 2014
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.
per isakson
per isakson on 14 Sep 2013
*A modest wish:*
  • The tag "oop" should qualify the post for the Category: Object Oriented Programming.
Walter Roberson
Walter Roberson on 29 Jun 2012
Walter Roberson
Walter Roberson on 29 Jun 2012
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 ;-)
Walter Roberson
Walter Roberson on 29 Jun 2012
Walter Roberson
Walter Roberson on 28 Jun 2012
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.
Sean de Wolski
Sean de Wolski on 28 Jun 2012
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.
Daniel Shub
Daniel Shub on 28 Jun 2012
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?
Jan
Jan on 28 Jun 2012
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.
See Asnwers: me not like new layout for more details of my personal opinion.
Adam Danz
Adam Danz on 16 Jan 2020
As of today, the new layout is wider! :)
TAB
TAB on 28 Jun 2012
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 ?
Randy Souza
Randy Souza on 28 Jun 2012
This regression should be fixed now.
Randy Souza
Randy Souza on 28 Jun 2012
We're aware of this regression (which somehow we manage to introduce seasonally...), and will get a fix out ASAP
Jan
Jan on 28 Jun 2012
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.
TAB
TAB on 28 Jun 2012
Actually I am talking about the list which shows my all the answers. Please see here
The oldest answered thread is on the top.
Walter Roberson
Walter Roberson on 28 Jun 2012
Walter Roberson
Walter Roberson on 28 Jun 2012
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.
Jan
Jan on 28 Jun 2012
Is a minimal title length of 4 words useful?
Walter Roberson
Walter Roberson on 28 Jun 2012
Yes, that worked. Perhaps it was the title length that was the problem.
Randy Souza
Randy Souza on 28 Jun 2012
When you have a chance could you try your edit again and see if it works? Thanks!
Walter Roberson
Walter Roberson on 28 Jun 2012
I was not changing the title, just the body.
Randy Souza
Randy Souza on 28 Jun 2012
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.