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What is missing from MATLAB?

Asked by Paulo Silva on 14 Feb 2011

Latest activity Edited by Rik on 27 Oct 2019 at 17:18

Accepted Answer by Walter Roberson

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431 views (last 30 days)

I'm curious, is there something you wish to do with MATLAB but you can't, maybe something you can do with other similar software but can't with MATLAB?

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Jeff Owen on 2 Jan 2018

When inserting text into a figure, Matlab gives 'left, center, or right' as options for horizontal placement. Why not 'top, middle, and bottom'? I have a vector of text strings, the top of which I want to position at the top of the graph, but the placement is automatically 'middle'. The length of the vector changes from time to time. It would be clumsy to have to re-calculate the placement coordinates based on the length of the vector. Easier if I could just say 'top'.

Jeff Owen on 2 Jan 2018

Oops, turns out it is there. I just tried 'VerticalAlignment','top' and it works. Should be included in the help file associated with 'text'?

Stephen Cobeldick on 9 Jan 2018

"... horizontal placement. Why not 'top, middle, and bottom'?"

Because top, middle, and bottom are vertical alignment, not horizontal alignment.

"Should be included in the help file associated with 'text'?"

In the help page: "For a full list, see Text Properties", which takes you to the page describing all of properties of the text object. These are listed in their own dedicated help page (just like with every other graphics object).

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113 Answers

Answer by Walter Roberson on 14 Feb 2011

Accepted Answer

The result of every expression should be further indexable by all of the index methods. This includes not only function calls but literals or expressions: e.g.,

(1:3:20)(K:K+1)

or

[struct('hello',A+5),B].hello

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MINATI on 25 Feb 2019

Also in solving ode (BY bvp4c) if we take variation of any parameter in X-axis when previously f ' varies with x

Ref: https://in.mathworks.com/matlabcentral/answers/396548-how-to-plot-for-t0-5-y-axis-vs-nt-ranges-from-0-1-to-0-5-in-x-axis-where-alre

Adam Danz on 27 Oct 2019 at 15:37

I searched for this thread solely to add this recommendation only to find that not only has it already been added but is the most supported suggestion.

The use of literals in expressions has been available in Python and I disagree with some of the (8 year old) comments above that such practice would be cryptic. On the contrary, it's pretty intuitive what the following lines do:

n=3
[1,2,4,7,11,14,16,17](n)
% hypothetical ans:
% ans = 4

Rik on 27 Oct 2019 at 16:41

@Adam, I think we are almost there. The example given makes me shudder with the though of how novice users will misuse this to strive for more compact code instead of better readable code.

Your example makes sense, but that tends to be true for most constructs. Currently (R2019b) you can do this:

n=3;
if ~verLessThan('matlab','9.7')
    table([1,2,4,7,11,14,16,17]).Var1(n)
end

Edit:

I just tested this on R2015a, and it already works, despite the release notes suggesting otherwise. That very same release notes search suggest this isn't actually something new, but is actually something that was ostensibly removed in R2010a.

%both of these work in R2015a (and presumably most releases):
n=3;table([1,2,4,7,11,14,16,17]).Var1(n)
n=3;struct('Var1',[1,2,4,7,11,14,16,17]).Var1(n)
%the struct line does error on R13 (v6.5)

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Answer by Jan on 14 Feb 2011

A long term supported version!

The current policy to fix bugs mainly by shipping a new release has the important drawback, that a new relase includes new bugs ever. If reliability is extremely important, e.g. for the prediction of the outcome of surgical operations for children, MATLAB is a fairly good choice, as long as a program runs only on the release it was developped on. I must be able to reproduce the results of a published medical study for 10 years. If such a study needs 5 years to measure the long term effects of a medical treatment, it is really unclear, if I can run MATLAB 2010b in the year 2025. Therefore MATLAB is actually not suitable for a long term study -- but there is a good argument to use it in spite of these facts: The alternatives are even worse.

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Jan on 26 Apr 2012

There is a new service pack for 2010b, although it is 2012 now. I do not have 2010b, such that I cannot download the SP2 and check the improvements. But I'm positively impressed by this special support activity!

I think it is worth to announce this update in public, because it increases the user's trust in the reliability of Matlab substantially.

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

dpb on 25 Feb 2019

Hadn't seen this previously until last activity link was adjacent...but it's still most apropos to real world.

Can't agree with Jan/Robert more -- in nuclear power generation field we were expected to keep similar abilities to reproduce safety-related calculations for "the life of the plant" which began as the 40-yr lifetime when applications were filed. Many of these plants are now well past that and have foreseeable futures extending another 20 years or more.

Hence, we were never able to use MATLAB for such because it wasn't stable.

Of course, it's impossible to now rerun old LIFE cross-section calculations on the Philco-3000 I ran in 1968, but at least we did have a traceable migration path.

"Geezer Alert!"

Until building inspector/fire marshall put end to it for possibly exceeding design floor loadings and the fire-safety issue, the entire outside halways of the office building were lined from one end to the other with metal shelves stacked full of "greenbar" folders of computer output. One overnight run would generate roughly 12-18" stack of printout, almost a hundred of us each doing that virtually every night added up to a lot of paper! Eventually they rented the old PigglyWiggly store and turned it into the repository for filing/retrieval identification before shipping them to the salt mines in Hutchinson, KS, for long term storage.

https://www.undergroundvaults.com/about-us/hutchinson/

http://www.kansastravel.org/hutchinson/kansasundergroundsaltmuseum2.htm

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Answer by Matt Fig on 14 Feb 2011

Real pass by reference.

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Peter O'Connor on 15 Feb 2011

should just have an option to create matrices that act as if they were subclasses of handle (pointers).

ie a=rand(1,1000000); b=a; a(1)=2; takes a long time, a(1)~=b(1)

a=*rand(1,1000000); b=a; a(1)=2; would be fast, a(1)==b(1). this'd be practical if calling functions to modify, not copy, a large matrix.

Malcolm Lidierth on 27 Apr 2011

Peter

How about this?

classdef databucket < handle

properties (Access='public')

Bucket

end

methods

function obj=databucket(data)

obj.Bucket=data;

return

end

function varargout=subsref(obj, varargin)

varargout{1:nargout}=subsref(obj.Bucket, varargin{:});

return

end

function varargout=subsasgn(obj, varargin)

varargout{1:nargout}=subsasgn(obj.Bucket, varargin{:});

return

end

end

end

I've created a set classes that do something like this using data on file, either memory mapped or accessed using low-level i/o so the "Bucket" can be many Gb without having them in memory all at once. With extra work to overload size, double etc and make X(:) a special case, these "nakhur" classes can be used anywhere a double precision array can be used in m-code.

owr on 21 Jul 2011

Malcolm, databucket is nice but an issue is that subsref in objects is much slower than in native arrays. Try this:

% Start Code

N = 100000;

d1 = randn(N,1);

d2 = randn(N,1);

db1 = databucket(d1);

db2 = databucket(d2);

dres = zeros(N,1);

dbres = zeros(N,1);

tic;

for i=1:N

dres(i) = d1(i).*d2(i);

end

nativetime = toc

tic;

for i=1:N

dbres(i) = db1(i).*db2(i);

end

objecttime = toc

% End code

In terms of the original question though, Ive managed fine without explicit pass by reference. But I can understand why one would want it.

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Answer by Doug Hull on 14 Feb 2011

The most effective way to put in an enhancement request for MATLAB is shown here.

It is fine to discuss things, but this forum is not guaranteed to be seen by the right people. The above link is.

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Jan on 14 Feb 2011

I suggest: Discuss at first here, forward the results afterwards.

Michelle Hirsch on 17 Feb 2011

I'm certainly watching the discussion! Jan's idea is a good one. You may want to mention if a particular suggestion happened to get lots of votes.

Thanks to all of you for your input.

Julian on 21 Apr 2011

Doug, may I ask how does one view/navigate/search the enhancement requests submitted this way? Mathworks.com search allows you to search Bug Reports (for example), but I could not see "enhancement requests". Thanks.

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Answer by Aurelien Queffurust on 18 Feb 2011

What is missing in MATLAB?

Here are my two quick thoughts for today :

1) More choice in default uicontrols:

Currently , user interface controls include push buttons, toggle buttons, sliders, radio buttons, edit text controls, static text controls, pop-up menus, check boxes, and list boxes.

I would like to have more custom pushbuttons . I would like to be able to modify the borderwidth (like for uipanel) , to choose another form than rectangle or square like circle , triangle ... I really feel frustrated not to be able to build a GUI with such components . Currently the only thing I do to enhance the design of my softwares is to use CData to add icons ! I always try to find the best backgroundcolor for my GUI ...changing colors is possible but not the form/appearance of the uicontrols.

Except uitable which is quite new, I didn't find any major improvement to build GUI since many years.

2) Documentation in another language

What about a French doc ?!! Translating the doc in Japanese was possible , so doing the same thing in French should be also possible .

Aurélien

My Blog for MATLAB geeks

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Steven Lord on 1 Sep 2016

That is a known issue captured in bug report 1376893.

Steven Lord on 22 Sep 2017

Bug report 1376893 was marked as fixed in release R2016b, and the Release Notes for MATLAB in both release R2017a and release R2017b say that loading apps in App Designer is faster.

Steven Lord on 13 Sep 2018

In release R2018b, the Release Notes has two entries relevant to this question:

"Building Apps: Faster canvas interactions in App Designer"
"Running Apps: Faster startup time for apps"

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Answer by Jan on 14 Feb 2011

It would be very helpful, if the Mex-interface is completely documented. Especially the inplace write access to variables passed by reference is a holy secret - although it is possible already and would be much more efficient.

2 Comments

Royi Avital on 31 Aug 2012

+1

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 14 Feb 2011

Graphic support for arbitrary unicode characters.

3 Comments

Ian on 15 Mar 2011

yes please! surely matlab should be unicode friendly by now!

Walter Roberson on 30 Jun 2016

(This has been added in more places, as of R2014b. If I understand correctly there are still a few places that cannot handle Unicode; some parts of Simulink, I think I read, and the TeX and LaTeX interpreters do not have Unicode support.)

Walter Roberson on 27 Jul 2017

I have been able to use unicode characters with TeX, but not with LaTeX.

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Answer by Walter Roberson on 16 Feb 2011

Exposed documented serialization routines. Currently, to transmit Matlab variables to a different process, about the best method available is to save() to file, send the binary file, read the binary and write it to disk, and load() the variables.

Better methods must exist already for use with parallel processing, so it would help to expose and document them.

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Ian on 15 Mar 2011

I would really love to see this too, even if all we have access to is the byte stream result of save we could route somewhere else. Ideally there would be a defined intermediate format.

Mike on 14 Sep 2011

Yes, Something like this is needed.

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Oleg Komarov on 17 Feb 2011

Anti-aliasing... MYAA

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Michael Johnston on 3 Aug 2011

Yeah, it's kind of ridiculous that we need to go to the File Exchange to be able to produce reasonable looking figures. The figure export options in MATLAB are pretty weak because they're not WYSWIG... lots of trial and error and visits to File Exchange required to produce something that looks decent in a PDF.

Walter Roberson on 30 Jun 2016

(Anti-Aliasing was improved from R2014b or a release soon after that. I gather it still has some oddities as of R2016a.)

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Answer by Walter Roberson on 14 Feb 2011

Programmatic layout routines. I had to create my own, one pass to shrink-wrap a control to the size it needs to hold the value(s), and the second pass to position the control relative to another control.

Exporting from GUIDE produces completely unmaintainable coordinates. It is not an option for producing maintainable software.

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Adam on 22 Mar 2019

I tend to use the GUI Layout toolbox for this kind of thing.

Steven Lord on 22 Mar 2019

I've forwarded this particular answer to some of the people responsible for App Designer.

Adam on 22 Mar 2019

I would also agree with Image Analyst on App Designer. I like some aspects of it and the direction it promises, but I don't find it in any way usable, for numerous reasons, a few of which I've passed on, others I have probably forgotten as I haven't used it for quite a while now.

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Answer by Ben Petschel on 8 Jun 2011

1. Distinguishing variable from function names in M-Lint. To get around the current limitation, "declare" which names are variables and which are functions, e.g. with %#fdef and %#vdef statements somewhere after the help header. These could be generated automatically e.g. via a dialogue box that asks the user to tick the boxes as to which ambiguous names are which. It would be useful for detecting uninitialized variables and other common typos.

2. Allow pausing/monitoring/debugging calculations mid-flow, e.g. with a pause button, or breakpoints that can be added during program execution, or a variable monitor window that displays variable values in a given workspace while the function/script is running. Would be very useful for monitoring long calculations without killing them.

3. multiple-line anonymous functions, or allow function declarations in scripts.

4. function calls with named arguments and default values in the function definition, e.g. "function f(x=[],n=length(x))" and "f(n=1)".

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Steven Lord on 15 Sep 2016

As of release R2016b you can now define local functions inside of script files.

Walter Roberson on 15 Sep 2016

That is a good step towards solving a common problem (though one I probably would have solved by expanding the error message...), but I suspect that now more than ever people are going to be wanting to copy and paste entire scripts with functions to the command line.

Steven Lord on 12 Sep 2019

Release R2019b allows you to declare specific restrictions (and default values) for input arguments. See more in the Release Notes and the documentation page to which that note links.

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Answer by Walter Roberson on 14 Feb 2011

An equivalent to the ?: operator, in which the unselected part does not get evaluated.

3 Comments

Jan Rubak on 14 Feb 2011

I've wished for the same, especially for use in anonymous functions.

David Goldsmith on 16 Mar 2011

"I've wished for the same" many times...

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Peter O'Connor on 15 Feb 2011

ability to enter default inputs like in python as in function out=foo(bar,bar1='arr',bar2='yarr') ...

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Walter Roberson on 12 Sep 2019

That's some change!

Adam on 13 Sep 2019

I hadn't even noticed R2019b is out. The e-mail notifications of a new release seem to be a little tardy I've noticed! Not that I really need the new release as soon as it is out though.

Rik on 13 Sep 2019

They're not fully done implementing it anyway; the MinGW compiler installer isn't working yet. I hope they will post something there when it is, because I will probably forget to install it untill I'm getting weird errors...

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Answer by Daniel Shub on 5 Apr 2012

A function to check if a string clashes with an official MATLAB function. Something like Jan's UniqueFuncNames, but with support for all MATLAB toolboxes. Preferably something that can handle different MATLAB versions and input classes. In other words randi exists in 2012a, but was it a function in r2008a or is there an fft function for class int16. The "which" function is helpful for your current version, but only for toolboxes you own.

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Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

Walter Roberson on 30 Jun 2016

I have started playing with Virtual Machines on my Mac. I might still have an XP install disk around, so I could potentially install quite a few versions back. However, I have not found any way of figuring out the names of the internal routines that do not happen to have a corresponding .m file for documentation purposes.

Jan, do you have an automated discovery routine that can be pointed at a base installation? Easiest would be if it did not require running the release so I didn't have to install the old OS's.

I do not have access to all toolboxes, but we could at least get somewhere.

Steven Lord on 1 Jul 2016

In release R2014b we added capability where MATLAB suggests which MathWorks product is required for an undefined function, which is a step towards what was requested. See the item "Suggested MathWorks products for undefined functions" in the Language and Programming section of the Release Notes for MATLAB for release R2014b for more information.

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Answer by Walter Roberson on 14 Feb 2011

A notation to be able to represent multi-dimensional data, instead of having to cat(N,...) the dimensions together.

This notation should in turn be understood by (e.g.) load routines

1 Comment

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 14 Feb 2011

A way to return multiple outputs from a function in an expression context, without having to resort to using a separate assignment statement.

Even if at the beginning this only allowed selecting one output to return by discarding the leading N outputs, that would help .

This is functionality that cannot be written at the user level.

2 Comments

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

dpb on 16 Mar 2017

Does not Octave have at least some of this capability I think I recall seeing? I agree (and added my vote for the Answer previously); just ran into another case on a forum query the other day where temporary created for no other reason clutters up the workspace...

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Answer by Walter Roberson on 15 Feb 2011

Short-circuiting vectorized conditional tests. This might require introducing a new keyword.

For example,

x > y/2

would normally compute the entire element-by-element vector x(K) > Y(K)/2, and then that vector would be processed within whatever expression was around it. For example,

find(x > y/2,1,'first')

or

if any(x > y/2)

But logically these don't need the entire vector result, just a single scalar result.

A lot of the time people are working with vectors too short for BLAS to kick in, but long enough that the time savings of short-circuiting would add up.

Imagine, for example, a new keyword "first":

find(first x > y/2)

or

if first x > y/2

"first" could return either 0 or [] if not found; [] would be more consistent, and ~[] is false so ~first would work like ~any(). On the other hand, what it should return so that it works with find() and logic conditions is a good question.

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Royi Avital on 21 Jun 2013

What's the difference between FEX and MEX?

Walter Roberson on 21 Jun 2013

FEX is the MATLAB File Exchange. MEX is the MATLAB API and compiling tool for C, C++, and Fortran to interface with MATLAB.

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 16 Feb 2011

More flexibility to work with I/O streams rather than having to have everything in memory.

As a simple example: unzip a single file starting from the current position in an I/O stream, rather than having to unzip to disk and read the resulting file.

2 Comments

Walter Roberson on 17 Feb 2011

I think it would be acceptable for this purpose to introduce a new IOStream object, with IOStream(fid) pulling out the object for the file id #fid . To start the basic properties of the IOStream would be the fields you get from applying fopen() to that fid.

A Position property when read could substitute for ftell(fid), and when set could substitute for fseek(fid,POS,'bof') .

Mainly, though, by having a distinct object class wrapping the fid, it would become easier to overload methods, especially in places where a file name string is expected as the first parameter.

imwrite(Array,IOStream(4)) would write to the given stream rather than to a file name.

This becomes more powerful when you allow IOStreams to become associated with blocks of memory, as per traditional unix memmap semantics -- which allow dual access through the fid and through memory

Or perhaps it would be better to have an IOObject class with subclasses for "stream" (non-seekable) and "block" (seekable) objects. That leads into possibilities such as asynch reads with callbacks, and scatter-gather I/O... maybe even DMA to devices...

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 16 Feb 2011

Pipes / popen() / ability to communicate interactively with other programs without having to use tcp/udp .

1 Comment

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 18 Feb 2011

Inspired by Carl's csvread requests:

A textscan format specifier indicating that a date was expected at that position, possibly including embedded blanks. A modifier would allow specification of one of the standard date format numbers. Output would be a serial date number.

Extra points for a format specifier that allowed the standard date elements, such as

%t{mmm yy, HH:MM}

2 Comments

Walter Roberson on 30 Jun 2016

(This was implemented about R2014b.)

Walter Roberson on 27 Jul 2017

(However, handling spaces in a %D format requires that the WhiteSpace property be set to exclude spaces.)

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Answer by David Goldsmith on 16 Mar 2011

Multiple inspector instances in one instance of MATLAB: I want to be able to "inspect" more than one object at a time (e.g., to be able to compare property values); presently, I have to launch a new instance of MATLAB for each distinct inspector instance I want to use simultaneously--a tremendous waste of resources! (Don't worry, I'm submitting a formal enhancement request.)

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Image Analyst on 26 Aug 2013

Yes, that's it! I think it's a major omission that this function doesn't come up when you search for "color" in the help, and it's not even listed as a "see also" in the ColorSpec page of the help. I'll send in a feature request for that. Thanks for telling us about this function.

Jan on 28 Aug 2013

@IA: It is easy to find:

docsearch color

Then it is about the 600th(!) element in the list on the left, when you sort the results alphabetically, what has been possible in the help browser of R2009a. In R2011b I do not find uisetcolor through docsearch at all. And after too many negative opinions I'm not eager to search in the help browser of R2013a.

So you are right: This will be an important enhancement request. I post a question here also, because it will be published earlier than the modified help text most likely ;-)

Walter Roberson on 28 Aug 2013

R2013, if I type uisetcolor into the GUI search engine, it shows up without difficulty. But if you tried to search for it without knowing the right verb (e.g., if you were looking for "pick color") then good luck.

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Answer by Dan K on 27 Jan 2012

A true polar plot. I've been using an old copy of mmpolar (thanks Duane) for years. It seems ridiculous that the built in functionality has hard coded axis labels,etc. It's even brutal trying to adjust things that can be accessed, since the underlying coordinates are all Cartesian.

2 Comments

Walter Roberson on 28 Jan 2012

Also, we get a surprising number of requests for log-polar plots. Yes, that causes problems for rho that are negative, and requires an infinite amount of canvas to represent from rho = 0 to any positive rho, but people want it anyhow.

Steven Lord on 30 Jun 2016

Release R2016a introduced the polarplot and polaraxes functions.

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Answer by Ken on 6 Feb 2013

What is missing in MATLAB?

Here is my quick thought for today (and most days when editing large sequences of code) :

In the native editor, it is nice when clicking on the if, try, for, etc... beinning construct or the end statement and it reference the line that may be far off the screen for it paired construct beginning/end but why hasn't anyone implemented the begging construct highlight to also include any of the else/catch in between constructs?

It would be nice when reviewing someone else's code to simply click on the beginning logic construct and see all sub blocks (if any) along with the location of the end construct statement.

1 Comment

craq on 3 Apr 2013

I wondered that myself, especially since clicking on the else will show you the corresponding if. I'd add switch/case to your list.

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Answer by Jim Hokanson on 11 Apr 2013

Create a formal website for Matlab suggestions.

This isn't necessarily for Matlab as much as it is TMW in general, but what's really missing is a more appropriate setup for this type of question. I would really like to see TMW take on National Instruments model of the NI Idea exchange.

I realize this question, and similar questions like it, are perhaps meant to be banter or office discussion topics or whatever, but I think in some small way some people may hope that these answers influence company policy. As Doug points out (Answer by Doug Hull on 14 Feb 2011), the only official way to try and do this is through the enhancement request. Having submitted many enhancement requests myself, I find this route very unsatisfying.

I would prefer these requests to be public with their own rating system, similar to the NI idea exchange. I think this is a much more satisfying approach for users to provide feedback and provides TMW with the ability to see how other users feel about the suggestion. It might also be more obvious to users and encourage more participation if something formal like the idea exchange existed, instead of hiding enhancement requests behind support or in answers to random questions in the Answers section of the website.

Here's a link to the idea exchange I find the most relevant (NI Labview) but a google search may provide a more persistent link ...

http://forums.ni.com/t5/LabVIEW-Idea-Exchange/idb-p/labviewideas

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Answer by Sean de Wolski on 14 Feb 2011

Mathcad-like sheets, where things can be easily displayed for the purpose of someone checking your calculations.

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K E on 12 Jan 2012

And you could insert figures/links/cartoons

Walter Roberson on 30 Jun 2016

("live scripts" as of R2016a goes part way towards this. But only for scripts, where-as I write nearly all my non-trivial code into functions.

Steven Lord on 15 Mar 2018

In release R2018a, we introduced the ability to create live functions and to debug code in the Live Editor.

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Answer by Walter Roberson on 14 Feb 2011

Explicit render to a buffer (array). There are some things that this makes much easier!

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Walter Roberson on 14 Feb 2011

Think of getframe() or saveas()'s ability to save an interactive image to memory or a file. Now skip the getframe() or savas() step by allowing the user to say, e.g.,

renderer buffer VARIABLENAME

and have the pixel results written directly to the variable. You'd possibly need a dots-per-inch kind of parameter in order to determine the drawing density and the virtual screen size, and an option to only capture between certain coordinates would be nice.

For example, the other day someone asked a question in cssm: they had constructed a shaded patch and wanted to capture the pixels along the surface of it for use in further processing. Not an easy task with the current rendering, especially if you want higher resolution than is available on your screen.

Oh yeah, and this render-to-buffer option should be available in batch mode!

Walter Roberson on 15 Feb 2011

Rendering to a 3D array would naturally result in RGB. Rendering to a 4D array might usefully include alpha information in some cases. I imagine that in some cases people might want to render to CMYK or YCrCb; at the moment there are a few routines that can translate RGB to CMYK or YCrCb but those need to stay within the gamut that is representable in both, and I don't know that it would be a priority to support full gamuts for those color spaces.

Now as to what rendering to a 2D array should mean... *If* the rendered area did not include any ticks or axes marks or text() or line() or patch() objects with interpolated shading... if, in other words, everything being rendered was exactly representable in terms of the current colormap, then rendering as pseudocolor indices might make sense. It does not take much, though, to destroy this -- for example, there is no current way to specify that plot lines or plot markers are to be drawn in terms of a pseudocolor index. The standard colors such as 'r' are defined as being in a "system colormap" outside of any figure colormap.

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 14 Feb 2011

eval() a char array or cell-string array as a multi-line input, allowing continuations and multi-line constructs such as

if (condition)
  %do something
else
  %do something else
end

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Bjorn Gustavsson on 3 Mar 2011

Amazing/amusing!

eval(sprintf('for i1 = 1:10,\n if i1>3\n disp(i1) \n else\n disp(''i1'') \n end \n end\n%%a comment\n'))

Ben Petschel on 12 Nov 2013

I don't understand - statements like

eval('if 1, disp(''a''); else, disp(''b''); end')

work from at least r2010a onwards

Walter Roberson on 12 Nov 2013

Yes, Ben, but that string does not contain multiple lines. Commas and semi-colons do not mark the end of a line.

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Answer by Walter Roberson on 17 Feb 2011

Better integration with perl.

Currently it is necessary to write the perl script to a file and invoke perl() on the file name. Arguments after the file name are permitted but not options before the file name. This makes it impossible to use any of the perl command line options, especially the -e option to designate a short in-line script.

For example,

perl -pe 's/^/ /' foo.txt > newfoo.txt

should ideally be accepted just like on shell scripts lines, but people could probably get used to

outstring = perl('-pe', 's/^/ /', 'foo.txt'); if ischar(outstring) fid = fopen('newfoo.txt','w'); fwrite(fid, outstring); fclose(fid); end

Manual redirection is a nuisance, but having to write trivial scripts to a file in full form (without the benefit of -n or -p even) keeps perl from being used to its full benefit.

1 Comment

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a. But python integration is advancing.)

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Answer by Walter Roberson on 1 Mar 2011

Extend the : operator so that if there is a value on the left side but not the right side, that the implied right limit is 'end', and if there is a value on the right side but not the left side, then the implied left limit is 1.

A(5:) -- to be equivalent to A(5:end)

A(:4) -- to be equivalent to A(1:4)

3 Comments

James Tursa on 16 Mar 2011

Like Fortran :)

Walter Roberson on 16 Mar 2011

All of the greats borrowed from each other ;-)

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 9 Jun 2011

Controlled time limitations.

You could start timers, and the timers could throw error(), but the timers are not parented to a code block so you cannot try/catch to control timeouts.

These time limitations I'm referring to are "non-cooperative", in the sense that the code being invoked should not have to have been written to know the time-out protocol you are using and should not have to check particular state variables or what-not.

Ideally even BLAS-level operations could be interrupted.

For example, I might want to code the equivalent of, "Give eigs() 5 minutes to come up with the solution, but if it hasn't converted by then, stop that approach and hand off to eig()"

Or I might have a function whose workings I am not familiar with. Or perhaps I'm running a unit-test framework or a framework to test class assignments.

Are the MATLAB Contest time limitations not programmable in MATLAB ?

1 Comment

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Matt Fig on 2 Jul 2011

Use of wild cards and regular expressions with GET and SET.

get(gca,'camera*') % Should return 8 properties

2 Comments

Jan on 7 Jul 2011

@Matt: Getting the factory and default settings works for the root handle: "get(0, 'factory')". Using "P=get(gca); regexp(fieldnames(P), ...)" is an option, but not comfortable.

If additional fields have been attached to the object by "schema.prop", more than 8 fields are possible (even if this is unlikely).

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Ashish Bhatt on 12 Mar 2012

I wish matlab could auto insert the white spaces into the expressions. For example, if I write a+b in an m-file or script, matlab would be able to make it a + b that will save a lot of effort entering white spaces before and after every operator which I am not accustomed to. I am not sure if this functionality is there in other similar software.

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Sean de Wolski on 12 Mar 2012

@Jan, agreed - very dangerous.

@Ashish, you could write a function to this if it is very important to you. Just what you do here:

fprintf('I sometimes use C+%s','+')

?

Daniel Shub on 19 Mar 2012

I personally would love some sort of formatting help in the MATLAB editor. Maybe auto formating of whitespace (as long as it doesn't get it wrong) like it does with tabbing, or maybe mlint warnings:

This project uses spaces after assignments (a = b;)

This project uses spaces between operators (a + b;)

This project requires commas followed by spaces ([a, b, c])

Where I can set the coding style. Also auto warnings on name clashes (yes mlint should know the name of ALL MATLAB functions) and camelCase etc.

Walter Roberson on 30 Jun 2016

I would appreciate an auto-format that could take sections of code and apply formatting rules like space around assignment and space between operators.

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Answer by Walter Roberson on 14 Feb 2011

Memory mapping to the bit level.

3 Comments

Michelle Hirsch on 17 Feb 2011

Walter - could you elaborate on why you would want this?

Walter Roberson on 17 Feb 2011

To complete the memory mapping capabilities down to a level equivalent to C's struct()

nb: C does not specify which "end" of a word the bitfields fill from, and C does not specify the size of the "word" for packing purposes, just that if the current field is too wide to fit it will be put in to the next word. It would be good if these factors could be configured during the memory mapping.

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a)

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Answer by Walter Roberson on 14 Feb 2011

An ability to directly call routines written in another language by having a Matlab-level wrapper that took a structured description of how to marshal the arguments and unmarshal the results. Even if in the first version it was only usable to pass read-only values, it would make calling external routines much simpler.

2 Comments

Philip Borghesani on 14 Feb 2011

This sounds like LOADLIBRARY to me. How is what you want different from what currently exists?

Walter Roberson on 14 Feb 2011

I hadn't seen that before, but when I go through it it appears to me that there a a bunch of limitations that are not necessary.

One of them is that for the 64 bit version of Matlab you have to have a C compiler to use it. There appear to be others but I need to look more closely to see if there are ways to overcome the limits that I just didn't notice.

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Answer by Walter Roberson on 16 Feb 2011

Explicit fflush()

yeah, I know fseek() to 0 bytes relative to the current position does the same thing in POSIX, but Windows doesn't promise POSIX.

2 Comments

Walter Roberson on 17 Feb 2011

And I found evidence suggesting that fseek(1,0,0) and fseek(2,0,0) don't work :(

Walter Roberson on 30 Jun 2016

(This has not been implemented yet, as of R2016a. I do see that the existence of the 'W' and 'A' permissions of fopen() imply that flushing is normally continually done, but when you are writing code for efficiency or communicating with an external interface, you want explicit control over flushing. This is not "discard what is in the queue" flush, this is "ensure that the buffer is sent to the I/O system" flush, which traditionally has a non-blocking form and a blocking form.)

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Answer by Oleg Komarov on 19 Mar 2011

Axes properties should be kept independent and the level of customization should be similar to excel.

- For instance, when manipualting TickDir or TickLenght it should be possible to differentiate among the effect on the X axes and Y axes.

- Or, when setting Xcolor, it shouldn't propagate to labels or grids!

- It should be possible to add additional X,Y axes w/o creating additional axes objects.

In general I want to have a more specific control over axes properties.

1 Comment

Walter Roberson on 30 Jun 2016

(R2015a introduced some of these controls but under an undocumented name; R2015b used a different name and documented the facilities.)

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Answer by Walter Roberson on 13 Jun 2011

If there is an atan2() function, why isn't there an acot2() function or acos2() or asin2() ?? Equal time for arc functions!

1 Comment

Andrew Newell on 13 Jun 2011

We shall overco-o-ome! We shall overco-o-ome! We shall overcome some day-a-a-a-ay!

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Answer by Daniel Shub on 19 Apr 2012

I wish there were better functions for comparing performance across platforms and versions. Something like a stable bench on steriods.

8 Comments

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