What frustrates you about MATLAB?

I love MATLAB. It is so quick and easy to write software to do what you want. It has excellent debugging and profiling tools. It is cross platform, making code easy to share (assuming the other people have forked out for the not-so-cheap license). It has interfaces to other software.

However, there are some things about it that irk me. I'd like to hear from other people what things annoy them about MATLAB.

Interesting start of a thread, Oliver. I encourage all posters to write a single point per answer to make it easier for others to vote up answers they agree with.

There will, of course, be no accepted answer. It's about what you think.

It sounds like this question may overlap to some degree with this previous one: http://www.mathworks.com/matlabcentral/answers/1325-what-s-missing-from-matlab

Yes, somewhat, but not entirely. This is "What's missing + what's wrong?". My answer on cost is an example of the latter. But the other question is more positively phrased, so will undoubtedly get the lion's share of responses from loyal MATLABers. :)

Help and examples sections are not newbie friendly.

@Ozan Oguz: Please post an answer in the answer section, not as comment.

I'm very surprised, because it did not find any better documentation and more useful examples in any software package I've tested. Please add some explicit points for criticism.

Answer 1

MATLAB's figure rendering and exporting functions are so full of bugs and "features" it defies belief. The rendering is very slow and stalls computations - rendering should be in a separate thread and not delay computations (unless specified by the user). It is crazy that you can't have a seperate colormap per axes, either.

Agree completely. We actually gave a few of our undergrads the (daunting) task of learning MeVisLab for the purpose of rendering.

They need to rewrite the whole Graphics Stack of MATLAB.

Answer 2

• GUIDE is a such an underpowered mess. Very poor set of widgets, endless bugs and terrible performance in the Guide editor (try moving sets of elements with the keyboard and weep!). TMW has dragged along hidden support of more UI widgets likes tabs, why can't they just update GUIDE and bring it.them into the modern age? Yair Altman does more in one blog post than TMW does in each year's paired releases to make GUIs better in Matlab!
• UNICODE support -- why is TMW so far behind on this!?
• Graphics quality -- graphics and text should be anti aliased by default and better composited, the pixel vomit is unacceptable on such an expensive product and one where its competitors are so ahead in this regard.
• Poor OS X support. Failure to copy vector figures to clipboard is my biggest gripe.

I agree 100% regarding your GUIDE comment.

I can't agree more with you regarding unicode support.

You just say what we all want to say about it.

Answer 3

It's very expensive (unless you're a student), especially if you use lots of toolboxes. Fortunately my company pays :), but if I start my own company I'll think twice about (ok, before) buying MATLAB.

Also agreed. Fortunately my University has a campus license that includes almost, if not, all of the toolboxes.
I think when I graduate and look for a real job, I may make a professional license with a few of the toolboxes, either a requirement for the company, or I'll just buy it as a gift to myself.

If you pay a skilled engineer with 70 Euro per hour and he needs 200 hours to program and debug e.g. some image processing functions in Matlab, you spend 1400 Euro for a toolbox without standardized documentation and support.
Now let the programmer create an equivalent software with the free MSVC-Express version. Well, I assume Matlab helps to save more money than it costs.

The cost is a serious constraint, both personally and for the organization I work for. Personally as in it notably constrains the questions I can answer: buying a $2000 toolbox in order to answer questions for free is not a wise investment decision. At work, I'm trying to help someone stuck with a 2007b release who has a program that needs 2008a to run: their department cannot afford to update the license.

I am currently unemployed but when employed I'm mainly do business analyst type work within the financial sector. Recently to help make me more employable I started to learn programming c/c++ as well as looking at Matlab. I was luck I managed to get a hand-me-down copy of 2007, without this I would never have been able to afford Matlab.
But before you say if you can't afford it don't use it, think about this. When I get employed I will use the tools I know, if its Matlab that means a license. If I am luck enough to be in a hiring position I may be more likely to hire people who use Matlab if I can use it as well.
Mathworks has a challenging problem, paying for programmers to produce world class software and accessibility to help perpetuate your user base.

I often hear the argument that Matlab saves more than it costs, but what is forgotten is that there are a myriad of software tools other than Matlab -- most cost considerably less. So comparing Matlab and the associated cost with having pencil and paper is not a fair assessment. Also, I'd rather see the toolboxes combined but left at $1k. e.g. Combine all the Signal Processing toolboxes into one, combine all the control into one, all the financial into one, etc.

Matlab is great software and really useful. Yes, way too many toolboxes and some of them just repeat functions in other toolboxes. Combine them as JP suggested, which I would think reduces code maintenance, management and likely saves operational costs. It would also be a stronger selling point. Cost is huge for small companies and startups.. Really, is there a point to having 100+ toolboxes?

This is a point that I think should be emphasized more.

Students are required to learn Matlab in many engineering programs, and provided it for the low cost of a textbook. Compared to a license with a handful of toolbox in their area of expertise that they use regularly, the student price is roughly 1% of the actual cost.

For a large company with sufficient revenue, the full price might be bearable. However, if a group of students wants to bring a commercializable idea to fruition either while they are still students, or shortly after graduating, the cost is a substantial barrier to using Matlab in an age of lean startups. Of course, there are alternatives, but students just spent four years mastering Matlab, not those alternatives.

It would be great to see some graduated licensing scheme, or have a freelance license available that makes it feasible for small companies and independent engineers to use this software commercially.

@Stephen: Although I understand, that a cheap freelancer licence would be a benefit for freelancers, it is very clear, that especially their job is creating commercial software. And then the price of Matlab should be forwarded to the customers, but not to TMW! Why should TMW sponsor freelancers massively?

Perhaps there could be a MATLAB-Elements, like Adobe Photoshop, or a cloud version, again, like Photoshop: http://www.adobe.com/products/photoshop/buying-guide.html

There is the standard Photoshop version for $699, Photoshop Elements for $99.99 (a real bargain), and a monthly Photoshop Cloud for only $20 per month.

MATLAB and associated toolboxes are priced at a point where it is not feasible for non-students to use the software non-commercially, such as volunteers, or freeware / donationware, or low-budget NGO. TMW has no legal obligation to provide lower-cost licenses for those purposes, but we can still acknowledge the fact that personal licenses are more or less confined to the well-to-do individuals.

Answer 4

Using a C-compiler not included in the list of known compilers is horrible. "mex -setup" calls an M-file, which calls a PERL script, which creates a DOS batch file, which is interpreted by another PERL script, which calls the compiler through the command line interface.

Strange. A tiny M-file could create the same command line call to the compiler also. But it would be much easier to adjust it to a different compiler.

I wanted to add the optimization flag /arch:SSE2 in my MEX call in Matlab 2009a. This works with:
mex -O OPTIMFLAGS="$OPTIMFLAGS /arch:SSE2" func.c
Because I have to do this programmatically I need the functional form and tried:
mex('-O', 'OPTIMFLAGS="$OPTIMFLAGS /arch:SSE2"', 'func.c')
>> ERROR: flag /arch:SSE2 is not recognized.
Ugly parser! This is the correct calling sequence:
mex('-O', 'OPTIMFLAGS="$OPTIMFLAGS', '/arch:SSE2"', 'func.c')
So I have to split the string inside the double quoted section, although these double quotes are exactly needed to signal, that the string should not be split! This is a drawback of the complicated pipeline as BAT-> M-> PERL-> Compiler.

Jan, you can always edit *.bat files directly.

Answer 5

Overriding subsref and subsasgn in a class is spectacularly awkward.

The problem is this. Suppose you override subsref in order to change behaviour of obj(...). Then your subsref is also called for the syntax obj.propname. In order for it to handle this correctly (i.e. behave the same as the built-in subsref) it has to reimplement all the checks for access protections that are normally done by the system. For just how problematic this is, look at Daniel's answer to my question here.

Apart from this major difficulty, it's also inefficient for every subsref to have to switch on the indexing type ('.', '()', or '{}') on every call, and for the system to have to build a struct that includes the indexing type as well as the indexes.

As far as I can see, it would be so much better if the different indexing syntaxes called three different methods.

Wait until you try and get your overloaded subsref function to handle colon and the other "odd" indexing notation: http://www.mathworks.com/matlabcentral/answers/6764-overloading-subsref

You would have thought that with the major overhaul of the OO system that they would have gotten it much better. Often simple OO things are inefficient and complex things are near impossible.

Daniel: indeed!

Answer 6

MATLAB is lacking tools for saving movies in decent compressed video formats (e.g. MPEG4, H.264 etc.). Currently I find myself saving a huge list of PNG files, then converting these to a video in an external application, which is far from ideal.

Answer 7

plot legends are not always placed in the "best" position - quite often its right slap bang on top of the data...

You can click on them (the legend) and move to another spot (even outside the axes). Also you can position the legend as an object at creation time or after by asiging to a variable and using "set".

Answer 8

Lack of OpenCL support: TMW forces us to depend firstly on a toolbox for this functionality, and secondly on the vendor lock-in using CUDA. Mathematica builds this in to its core, not some toolbox, and provides both CUDA and OpenCL support so we aren't forced to a single GPU vendor.

www.gp-you.org hosts an open source gpu toolbox

I wish they supported Open CL as well.

I agree with this one!!! I'm a mac user and since macs don't use Nvidia graphics cards it is very difficult to use the GPU.

Happening to read Val's comment again just now: MacBook Pro's added NVIDIA graphics cards in June of 2012; I am using one of them right now.

Answer 9

• The lack of built in 64 bit compiler (MATLAB used to work with Photoshop out of the box).
• The graphics stack performance. It's so slow!
• Editor - I wish the editor could add rich text editing capabilities for code documentation (Adding LaTex, Graphs, etc...).

And the editor needs a block selection.

Answer 10

Frustrating factoids after living with Matlab since version 4.x:

1. Ambiguous use of parenthesis ([([( indexing operations and function calling )])]). I wish Matlab's syntactic sugar could differentiate between this two actions, using parenthesis and something else (i.e. like Mathematica's use of parenthesis vs square brackets)

2. Poor quality graphics (already mentioned in detail by other fellows)

3. Excessive "commoditization" or segmentation of functionality that should be part of the core Matlab product (e.g. signal processing, image processing, statistics, and pdes).

4. I wish there was better quality control when rolling out toolboxes. The seemingly lack of coding style/guidelines is particularly annoying. Even toolboxes meant to be used together have inconsistent syntax and seem a bunch of functions "bolted-on" to Matlab, rather than coherent extensions of M language.

5. I hopelessly wish there was first-rate support for functional programming.

6. Very poor support for time series and data structure requiring multiformat date/time indexing.

99nth. Non-specific gripe: Over time Matlab is becoming less and less my primary platform for scientific computing and algorithm development, and more often than not just a target for deployment (meaning re-writing whatever project in the M language) because the customer/client is using it, or because a particular toolbox is a time-saver. I remember the days of yore, when Matlab looked like a hammer and most problems looked like nails. Now I feel that the handle of the hammer is a Baroque wooden carving, richly ornamented, weighting 120 lbs... More surprising is the strange comfort of spending so much more time working with Mathematica's superhuman -indeed extraterrestrial- capabilities for algorithm development and testing, and the "translating" to Matlab upon request. I guess necessity is the mother of strange companions...

Commoditization is an excellent point. It should be an answer by itself.

Answer 11

The use of degrees as the unit for angles in some functions of the Image Processing Toolbox. For instance

• hough: takes arguments and returns results in degrees

as opposed to, for example,

• atan2: returns result in radians, like the majority of angular functions in most languages and maths packages.

Apart from the irritation of having to keep writing *pi/180 here and there (and forgetting to quite often), it also makes it harder to teach students to use grown-up units (radians) in their programs rather than degrees.

Similarly, why is there not a built in rad2deg.m, or deg2rad.m function? Sure it's easy to write yourself, but just a bit annoying that it's not there already.

It appears that rad2deg.m deg2rad.m radtodeg.m and degtorad.m all exist within the mapping toolbox. Now, I don't know whether I can use those functions without requiring others to have a license for the toolbox. This is dumb. Pick a name for the function pair and make them built-ins.

No element of a toolbox can be used by anyone who does not have a license for the toolbox. It would, for example, not be permitted to copy those files from the mapping toolbox and include them with your code that is intended to run without the toolbox.

Answer 12

Mesh doesn't accept class 'single' inputs.

Answer 13

The fact that once you schedule a low-level function, you cannot in any way stop it. Such as conv(zeros(umpteen,1), ones(umpteen,1)). A big red, working "stop" button would have been nice.

I like to run my scripts, insert break-points, then test stuff using command-line on the variables available. In recent versions, I have not been able to define new variables that way easily, having to declare them as global (??)

I would have really liked the core matrix-syntax to be even cleaner (not having scalars being 1x1 2d arrays for instance).

I would have liked some sort of extension of the matrix syntax into tensors.

I really hate the frustration when I go from compact, vectorized, readable MATLAB-code and have to dip my toes into "real" programming languages, where you spend most of your time concentrating on the implementation instead of the functionality :-D

Answer 14

1. I'd really appreciate improved MEX-debugging capabilities on Linux systems in regard to the user: Seriously, we're still using GDB? Launching MATLAB in CLI-only mode in order to see what your MEX is doing?
2. Customizable color schemes for C-files... what's the matter of applying only half of the personalized colors? Use ALL or NONE if two separate color schemes are too much to integrate: if I optimize the color scheme for personal visibility and oversight, coding C is nearly impossible as it results on dark navy blue keywords and dark green comments on black background.
3. Object oriented programming would be a nice feature. (I now, I now, it is supposed to be present, but there are so many times I develop OO systems according to OO concepts and design patterns and have to realize at the end, that behaviour isn't supported by MATLAB's OO-engine. It's more like "as-long-as-you-use-only-trivial-OO-concepts-you-wont-realize-it-just-looks-like-OO-but-in-fact-isn't"-concept. :(

Answer 15

I would love to just write x++; instead of x = x + 1;

I would prefer to write inc(x) and dec(x) instead of x = x+1 and x = x-1.

This has been discussed in CSSM repeatedly. It would concern MATLAB's fundamental methods for addressing variables. I do not assume, that this will be implemented.
But I see the benefit. A dirty C-Mex implementation is possible using some undocumented API functions. But I will not implement an instable method, which save micro-seconds, but can cause weeks for debugging.

Funny, in Simulink Stateflow (action language) this is already possible.

Answer 16

The figure-export is a pain, if annotation are used they will move about, not all of them and not much and not to any order (at least nothing i could recognise) but sometimes a few mm in the odd direction.

Also, quality of copied figures is poor (blurry lines/text) and requires workarounds like export_fig .

Answer 17

It can be very slow, compared to the same functionality written in, say, C.

For example, for loops filling in cell arrays are slow. Also, code like:

A = sin(abs(A)) .^ 2;

is (I believe) not optimized to do all three operations on each element simultaneously. Rather, it churns the entire array through memory 3 times.

However, it's getting faster all the time. :)

Now add the programming and debugging time to the runtime: While the C-implementation runs with the double speed, it take 8 additional minutes to be written, debugged and compiled. A serious programmer can estimate if the runtime of the program ever succeed 8 minutes, and if so, calling a C-Mex is the better choice and not harder than writing a pure C-function.

I want to have my cake and eat it. It would be great to never have to resort to a C mex file, but sadly I often do.

I hope it doesn't do what you described.
If it does, They need to optimize it fast.

Answer 18

FOPEN has lost its Vax-D support in Matlab 2008a without any notice in the documentation. The argument from TMW was, that computers needing this numerical format are not manufactured anymore and the further support will take too many resources from TMW.

Stopping the support without mentioning this in the docs took too many resources from me.

Sorry about that one (again). Hopefully Mike's File Exchange submission is helping you and others who were bit by this.
http://www.mathworks.com/matlabcentral/fileexchange/22675

@Scott: Thanks. My answer does actually not match the question, because this problem does not "frustrate" me in the present, but "frustrated" me in the past. I appreciate it, that such breaks in the backward-compatibility happen very seldom. See my positive estimation in http://www.mathworks.com/matlabcentral/answers/1428-what-do-you-like-about-matlab

I have prototype functions working that overload fopen, fread, and fwrite and provide seamless backwards compatibility for VAXD/G support (i.e., you don't have to change any of your code that uses VAXD/G options). When I get some time I will polish them up and submit them to the FEX. Be careful of the submissions 22675 etc noted above since they contain bugs.

@James: Thanks. I've published a C3D-File converter (format used in the motion-analysis), which is downloaded 20 to 50 times per month since April 2009. It seems that at least about 1000 other users suffers from this compatibility limitation also.

Unfortunately for me this is a continuing problem. ALL my data is in the vaxd format. I will probably have to pay a full time employee to convert all my files (1975 to present) and check that it is converting correctly. Mathworks has been working with me on fixing the freadVAXD function so I can upgrade from 2008a in the mean time. This is the first time I looked into different programing languages. Separating people from there data is never a good idea.

Answer 19

"load file.mat" saves 3 keystrokes compared to "load('file.mat')", but I've spent more than 600 keystrokes in answering desperate question in CSSM, Answers and goMatlab about using a variable as file name.

The HELP text of SAVE and LOAD explains the needed arguments explicitely. Therefore it is not Matlab, which frustrates me in this point, but the fact that a lot of Matlab beginners are overstrained by the tricky and actually not useful feature of non-functional forms of commands - and that even a good help text cannot intercept these problems.

Answer 20

The way that anything that turns char into cell arrays strips spaces when it does so. Sometimes -- often, in fact -- I want those spaces. Would it hurt to at least have the option?

Wouldn't mat2cell work?

a = 'aaa ';
b = 'bb';
c = ' C '
A = strvcat(a,b,c)

mat2cell(A,ones(size(A,1),1))

The strvcat() step adds spaces to short lines, and the mat2cell is going to preserve those introduced spaces.

Answer 21

To produce diagrams for a report is often quite frustrating. I've seldom try to do anything special because of the risk to waste my time and end up with a disappointing result. However, now I try and I'm indeed frustrated.

Background:

• A simulation study and I want to present the result in a few Trellis Displays (plot matrix)

• MsWord and I want to CopyFigure&Paste the diagrams into the report, i.e. use the meta file format (emf). I believe that with MsWord emf is better than eps. However, export_fig doesn't support emf(?).

• One Trellis Display contains 3x3x3=27 grouped bar graphs showing histogram data. It is readable and useful!

Approach:

• Put the axes on a figure, which has the aspect-ratio (and size) of an A4-paper

• Absolute units so that I can measure with a plastic ruler on the print-out and adjust the code based on the reading (without tricky calculations).

• Crop the white margins of the figure.

• Edit Copy Figure | Paste into MsWord | and finally convert to Acrobat PDF.

Causes for frustration:

• Some elements of the Trellis Display are not displayed on screen. OK, MATLAB had choosen OpenGL. Painters does a better job in this case.

• The "Trellis strip" above the bar graph interferes with the box of the bar graph. Adjusting the positions doesn't really help. OK, the order in which axes are created is important. I have to create the strip before the bar graph (or better use UISTACK).

• Handle graphic objects of the Trellis Display are dislocated on the printout. OK, I hadn't made sure "all" units were set to normalized before exporting/printing. The Mathworks calls MATLAB a high level language and ask me to handle this "feature" of PRINT. MLINT could at least have given me a warning.

• MATLAB doesn't provide a crop-figure function (Windows platforms). However, with TightInset I was able to improve my old crop_figure.

• The width of the bars vary. (I call that a bug.) In the worst case a few bars are only half as wide as the widest. I've seen something similar with IMAGE. In that case changing painters to zbuffer solved the problem, but not this time. OK, adjusting BarWidth seems to help somewhat. There seems to be a minimum width.

Will a new and better graphic support be part of R2011a? I've waited so long! However, this litany reduced my frustration a bit. Now, I will overlook the taints in my Trellis Display and do something useful.

/ per

Answer 22

Schedule keeps slipping on the DWIM (Do What I Mean) toolbox.

And that's the one that could send the entire MW development team to Geneva!

That brings to mind something that I read was posted on the Stanford University computer bulletin board sometime in the early 1970s:

     I really hate this damn machine!  
     I wish that they would sell it.  
     It won’t do what I want it to,
     But only what I tell it!  

I’ve certainly had days like that.

Answer 23

The database toolbox is way too sensitive: You have to use string commands in order to have linebreaks in your code, or you are doomed with one loooooooong sentence! It's also too picky regarding the syntax, considering it's supposed to support several different SQL languages.

Start giving out the source code for webinars a day in advance, rather than several days later. That way people can actually play around with the code, and the presenter can go through some functions etc but spend more time on Q&A and applications.

Call me old-fashioned but I much prefer the "old" printed User Guides for the Toolboxes. I'd be happy to pay for them. When I need to check if there's an update or additional info I'll go online, but for most purposes I just want to grap the guide to look something up quickly without cluttering my screen with help windows.

You can get some PDF manuals here and print/bind them at your local printer. I agree, the help windows are only useful if you have a specific command to refresh your memory about, but not if you want to get a big picture (for example, regexp is covered in several pages in the documentation).

Answer 24

plot(1:10,'b-',3*(1:10),'r')

Throws an error. MATLAB, you know how to plot against indices when there is only one vector, why not two after a line style string?

Answer 25

Once every now and then when I type a character or two at the commnd-line and hit "tab" for expansion matlab simply freezes, and I have found no way to unfreeze it - so it is just to kill the process and start over again. This is very frustrating since at times too much work have gotten lost.

I hope you've sent a report to the technical support team mentioning the Matlab and OS version.

Happens to me too sometimes.

Answer 26

I have been a licensed user of MATLAB for the past 20 years. I am also a big Mathematica user and sometimes use Maple and Mathcad and of course I love R and Python. I have enjoyed using MATLAB for my numerical work, but the licensing hassles have driven me to the point that I am considering just dropping it after all these years. I don't mind paying the (substantial) price for my license -- but then just let me do my work -- whether it is on my main desktop or my laptop. I used to just get the update CDs and my license number by email and no hassles. Are you really making more money by stopping piracy with all your licensing hassles? I doubt it. You are driving away your paying customers/user base. I sympathize with this (former) user: http://mybrainextension.blogspot.com/2011/07/aaaarrrrrrgh-matlab.html

Also I find the license manager cryptic for managing a small group of user licenses. If I have a license management task, I almost never open up the license manager and succeed on my first try; I always end up calling/emailing tech support.

Without doubt FlexLM is neither smart, nor user-friendly. I've struggeled with several other software package also, which use this license manager. The usual procedure is 12 minutes for installing the software, 2 hours trying to install the license manager, one hour for emails and phone calls to the technical support, who comes in the next day, look of what I have done so far. Finally the sessions end with something like: "I've called the developpers this morning and they told me, that you need the computer's name and nothing else." But after we typed in the IP, the software suddenly accepts the connection to the license server.

The FlexLM software is a really bad choice. It is very sad, that TMW has decided for this service, because all it does is impeding the legal usage of Matlab substantially.

The fact that if I want to deactivate an old version of matlab on a PC with 2 versions, since there is a new release out and flex deactivates all versions on the PC is a pain.... Why doesn't it just deactivate the one selected?

Answer 27

I know nobody writes big programs in Matlab (haha), but it sure would be nice to have a source code browser. I don't use simulink much, but there is a nice browser in there.

What do you consider big? How many lines?

What kind of features would you envision in a "source code browser" ?

Should this perhaps be over in http://www.mathworks.com/matlabcentral/answers/1325-what-is-missing-from-matlab ?

I'm using a > 200'000 lines of code program distributed to about 2000 M- and C-Mex-files. When I want to modify a specific feature, it would be nice to have a treeview to the dependent functions. But if e.g. the data are shared by using a large struct, there is not automatic solution to find the functions which read or write a certain substruct.
Without doubt an object oriented approach is required to manage "large" projects - but this does not mean object oriented syntax necessarily.

Answer 28

there are sometimes where you just have to kill matlab because it would rather complete a nonsense calculation rather than listen to I really didn't want to know quite that much. I swear this happens every time I have a short deadline on a presentation. Now I just want to go home, but I promised to do a presentation before I leave.

And when it breaks down or starts to annoy
Or grinds when it moves
And gives you no joy ...

Answer 29

Matlab is the greatest, but it bothers me to no end that microsoft excel does bar graphs, error bars, and in general does statistics in a much more straightforward manner than matlab. It should not be so.

Could you explain how?

Answer 30

removal of working version (from 6.5 onwards) on HPUX.

Answer 31

Difficulty publishing documents.

For calculation publishing, homework assignments etc, it's difficult to show values along the way and display them.

Sean - could you clarify? When I want to show intermediate values, I leave off the semi-colon in calculations and make sure I start a new cell after each value.

How can you publish the code of a fcn preserving M highlighting?http://www.mathworks.com/matlabcentral/answers/1405-publishing-in-matlab

You can publish function files (with M highlighting) since R2008a.

I have used Editpad Pro for all my text editing for years. It has a very powerful highlighting capability, and permits copying highlighted text as RTF. Fortunately, MATLAB's editor checks for updated files on disk promptly, so I don't usually have a delay when I save from EPP and swap to MATLAB. I use the GUI as my primary interface to MATLAB rather than the command line.

Hard to document equations (I use MathCad for this, but then it's a separate document from my code).

Answer 32

Not concerning MATLAB, but MATLAB Answer:

The latency caused by the automatic preview drives me crazy. It frustrates me, that there is a function implemented already, which disables the auto-updates, but this function is called after a large number of charatcers only. It would be extremely easy to set this number to 1 in the source code. But it seems like TMW waits until the next monthly update to include such improvements. What a pitty.

Ha. Solved: Create a short dummy answer at first. Reload the question page. Hit the "Edit" button before the page is completely loaded => A tiny inputbox opens in the top right corner on a blank page => without a preview window! Not nice, but not annoying anymore.

Just curious, what browser are you using?

Firefox here. This situation is discussed in the "Matlab Answers Wish-list" topic.

Answer 33

"It is cross platform, making code easy to share (assuming the other people have forked out for the not-so-cheap license)." This made me laugh. I have paid $100 for a student version of MATLAB. (I'm sure this is quite inexpensive compared to non-student versions of MATLAB, but that's $100 more than something like Python, and grad students do not typically have much in the way of extra money.) Now I can't buy the compiler toolbox. I can't pay for the privilege of taking the code I write on my desktop computer and using it on my netbook? I can't write an application to share with fellow students or professors? Users have a lot of other options for programming languages, and sharing your applications is a fundamental need for programmers that basically any of these other languages would satisfy. But TMW won't take my money for the same feature? I really think the compiler toolbox should be included in the base MATLAB installation, and since I know that won't happen any time soon (probably ever), I cannot understand why they wouldn't want my extra $30.

I also use MATLAB at work, where it is installed on a single computer while they decide if they want to shell out for more licences. I cannot recommend the compiler toolbox, builder EX toolbox, or spreadsheet link EX toolboxes to the company, because I cannot see the prices! TMW website won't show prices unless you give them all of your information in the first place. So I thought, "that's fine, they already have my information because I've already paid for their product". But since they see that I have a student account, I'm not allowed to even see the prices of other products that aren't available for the student version! Why on earth would they have this restriction?

In the end, MATLAB is neat. I love the IDE. I think the editor has features that are lacking from almost any other IDE in any other language. And the code generation/ease of use features for non-programmers are excellent. But given the amount that has to be spent to make use of your own code on more than one machine and the incredibly slow and under-featured GUI toolkit (that many others have already mentioned), Python + matplotlib seems like it's in my near future.

"grad students do not typically have much in the way of extra money" .... but they often have iPhones or the like.

"I cannot understand why they wouldn't want my extra $30." Regular price: $5000 for MATLAB Compiler, or $6500 for MATLAB Coder.

Mathworks is constrained by government contracts to sell to governments at their "most favorable customer" rates for equivalent products. The Student Edition versions are and will remain crippled in some respect so that they are _not_ "equivalent products". Deal with the limitation or be prepared to pay about $7000 for the software that is currently bundled in to the Student Edition.

Welcome to the real world. You don't get student prices at pennies on the dollar without *some* limitation.

I would love to describe the kind of budget trade-offs that have to be made in the real world, but unfortunately one of the other trade-offs that get made in the real world is that your company "confidentiality agreements" tend to become deemed more and more inclusive when your company is in financial difficulties.

"but they often have iPhones or the like." That's a straw man. Is the implication that I shouldn't complain about something being expensive unless I've devoted all of my extra money to it?

"Regular price: $5000 for MATLAB Compiler, or $6500 for MATLAB Coder." I would have liked the ability to see these prices listed on their web site. Also, these prices are astronomical. Are all of the toolboxes this expensive? I know MATLAB has some features that are unique to it, but how do companies justify this cost when Python + matplotlib + py2exe is free? I would expect that MATLAB would be on the losing end of many budget trade-offs.

As for crippling the student version, I fully understand that. It happens with many products, and is expected. But they could have allowed the compiler toolbox for the student edition without allowing the additional deployment toolboxes (builders, spreadsheet link). And they could disallow some of the other more specialized toolboxes (Phased Array System Toolbox, Aerospace Toolbox, Parallel Computing Toolbox, Distributed Computing Toolbox) that students are less likely to want, need, or be able to pay for. (Maybe these are already disallowed, I haven't checked.) There are ways to cripple the student version while still allowing students to have the compiler. And no matter what the current cost of the various products are, I will continue to believe that it SHOULD be the case that any programming language comes with a way to share applications.

If Python + matplotlib is so good, why is anyone willing to pay for Matlab? The truth is because Matlab is generally very good at what it does. You might not be able to pay for it, but I'm afraid that's really just tough chops to you because others will. Last time I checked, Matlab are not a charity.

If you care to look, there are other open-source alternatives to Matlab, but of course these are not yet as fully featured or reliable, hence people and organisations still being willing to pay for the real thing. Perhaps you could contribute to these if you feel strongly enough about it.

I don't know why you consider the open-source alternatives not as fully featured or reliable. Maybe Python doesn't have a Phased Array System Toolbox (or maybe it does, I have no idea), but the base capabilities of Python and MATLAB are very similar, and all of the extensions to Python are free. I would consider the (still free) combination of Python, matplotlib, py2exe, and the toolkit of your choice (Tkinter, wxPython, etc.) to be more fully featured than the base installation of MATLAB.

Also, I'm not frustrated because I'm unable (i.e., can't afford) to pay for it, nor am I frustrated that it costs money in the first place. (I'm certainly not asking MATLAB to give the code away.) All I said is I would like the opportunity to pay for the compiler.

5000$ is *not* an astronomical. In the real world - I mean apart from the university - a company pays 100.000$ a year for an educated programmer (brutto~=netto, unfortunately). Of course you can perform the calculations with free software also - Matlab has no witchcraft. But a company will calculate if it is cheaper to buy the established and well tested Matlab toolboxes: If the programming, debugging and tests consume 2 month less, the price of Matlab is actually negative. :-) I haven't seen a project in the last 20 years, whose costs were dominated by the software.

The assumption that students have iPhones is not meaningful here. Take into account, what a programmer could accomplish, if he or she does not waste time with playing around with a high-tech gadget.

I do not see a reason to sell the Compiler toolbox to students. Students can usually share their programs as M-file with other students having a student-version also. The professors can use licenses of the university usually. And a company is not allowed to use the student version at all.

If you want to ask TMW for prices, call your local distributor. I agree that the anonymous web-page access is not comfortable. Even the email contact is sometimes sluggish: It seems like there is still a student-flag in my account information, because the replies of my mails to the support start with "this service is not available for students...".
But whenever I spoke to a TMW employee personally, the contact was very friendly and efficient. They even called *me* actively after I could not solve a problem in the newsgroup. Therefore I strongly recommend to using a phone, even an iPhone if available, to get information from human to human.

Jan, I also had my account somehow linked to my ancient student edition. It was a quick email to one of the Matlab Central Admins to fix it.

If a student needs access to a program written using the student license, then they can pay the $100 for the student license. It takes 50 such students to equal the cost of one compiler license.

If the university staff needs access to the program, the university can use one of their compiler licenses. Universities get substantial educational discounts.

If someone outside the university needs access, then you have gone beyond student research in to "distribution". Let the university or the other party worry about the financing of a version that allows the compiler toolbox.

There is nothing that stops you from distributing your source to others. What do you distribute with Python: your source or an executable? Mathworks in no way blocks you from sharing your intellectual work with others; they can read the source and study the Mathworks documentation all they want.

Obviously, Andy, your formative years of computing were not the same years as mine: in the early 1980's buying just a C compiler was $2100US, which is about $4900US in today's money. Certainly groups such as FSF have done wonders in providing common software at good value -- but that doesn't mean that commercial companies are obliged to buy in to Stallman's philosophy that *all* computer software should be free (except for shipping and handling and the like) and that companies should only charge for the _service_ of customizing it to meet specific situations.

The organization I work for (which is *not* Mathworks or any related company) considers $50,000 the lower bound of being worth thinking about: if we can't gross at least $50,000 on something, then it isn't worth our cost of drawing up the contracts and having them checked by our lawyers and writing up proposals and setting up work plans and cross-checking intellectual property rights and scheduling people and the like. Suppose Mathworks is considerably more "agile" -- suppose they could do it for (say) $15,000. At the $30 price point you suggest, they would need 5000 sales -- and that wouldn't even cover the increased cost of support (since using the compiler is tricky) and installation costs. Is that realistic? Is it realistic that Mathworks could make the change for as little as $15000 ?

For my purposes, I'm talking about my ability to provide an application (compiled, not the code) for use by fellow grad students. Since I am a pure math grad student, requiring others to get even the $100 student version of MATLAB, which they would otherwise have no use for, is not a reasonable solution. And to answer your question about distributing Python, you can easily distribute either the source or a compiled executable.

"...but that doesn't mean that commercial companies are obliged to buy in to Stallman's philosophy that all computer software should be free..." As I have said a few times now, I'm not asking for anything to be free. I'm pointing out in the "What frustrates you about MATLAB" thread that I'm frustrated that I'm not given the option to pay for a product. I didn't think this was so unreasonable of a comment.

As for exact pricing, I only mentioned $30 earlier because that's what a lot of other toolboxes cost for the student version. Perhaps it could be more for the compiler, or they could offer less support. How many student versions do they sell? Is it unreasonable to think that they would sell 5000 versions of the compiler to users using the student version? In any case, I was just voicing frustration in what I thought was the appropriate place to do so. I don't think the burden is on me to come up with a pricing plan.

I agree that there is no point in their being so secretive about prices. Why not just post price tables on their web site?

They have a pricing plan: $US7100 gets you the compiler and base MATLAB together, with a right to distribute to as many people as you like for however much you want to charge them. Your counter-proposal is for a price much less than $100 per person.

This topic reminds me of Harlan Ellison's "Pay The Writer" essay, available on YouTube. (Caution: strong language.)

Anything written by Harlan Ellison should be approached cautiously.

Answer 34

That contour effects the clim range! I've used something along these lines:

pcolor(x,y,z1)
hold on
contour(x,y,z2,8,'w')

Just to see if the shape/location in z2 aligned with those in z1. Since matlab7 I had to use the 'v6' flag. Now I'm gently told that functionality is going out. So I guess I'd have to track every "contour('v6'" in all my code and replace it with something along the lines of:

pcolor(x,y,z1)
hold on
cX = caxis;
contour(x,y,z2,8,'w')
caxis(cX)

Which I find uglier and clunkier. Or I could shadow contour with my own wrapper where z2 is scaled to cX if there is a colour argument. But I prefer to avoid shading the mathwork's functions.

Answer 35

In the spirit of "do what I mean" while testing functions, the command history is oblivious to context. Frequently I'll start my tests ("runtests"), stop at a breakpoint and examine some variables ("look.at.this.object"), then kill the function and need to restart the test. In this situation, [up] [enter] does exactly what I said (repeat last command entered), but never what I want (repeat last command in this scope: "runtests").

Whatever I did while stopped in the debugger is completely meaningless in the base workspace. The command history would border on reading my mind if it followed which workspace commands were issued in.

If you have variable names being passed down using the same dummy variable names, or if both routines use the same global variables, then you might have good reason to want to repeat the same command in different contexts. The same goes if you are using shared variables.

Answer 36

At Walter Roberson's request I'm reposting this answer here.

Boredom Forecast: High(78/100). Discussion of Syntax.

First, get the preferred indentation by using "smart indent" in the Matlab Editor.

 for t = 1:1:26
    if 0<t<=4
        x1d(t) = 0.5*t;
        x2d(t) = 0.5*t;
    elseif 4 < t && t <= 7.
        x1d(t) = 0.5*t;
        x2d(t) = 3.33;
    elseif 7<t<=10
        x1d(t) = 0.5*t;
        x2d(t) = 10/3 - 0.5*(t-40/3);
    elseif 10<t<=26
        x1d(t) = 0.5*t;
        x2d(t) = 0;
    end
end

Second, as Paulo Silva points out, compound logical expressions, such as 4 < t <= 7 are not allowed in Matlab, Fortran, Pascal, ..., etc. Instead you have to write (for the convenience of the compiler-interpreter (writer)), 4 < t && t <= 7.

Count yourself lucky. In some languages you would have to write if 4 < t && (t < 7 | t = 7) etc.

This logical expression would take an eagle-eyed programmer anywhere from 10 mins to a day to check for errors (precedence rules for && versus |, etc.).

This is crazy. Any compiler-interpreter that rejects 4 < t <= 7 is doing so for purely lexical-syntactical convenience. This is not a code generation problem. Most 1st or 2nd-year computer science students could write a (character-by-character) program that would translate 4 < t <= 7 into 4 < t && t <= 7.

For me, the key to Matlab's success, and what attracted me, was the important syntactical innovation by Cleve Moler: a notation that made it easy to translate statements in Linear Algebra into a programming language. This is what IBM's Jim Backus tried to do with the FORTRAN (FORmula TRANslation) (56?) compiler. He succeeded, despite the sceptics, and Cleve Moler succeeded, despite the sceptics, to produce programming languages that are widely used in scientific computing.

So, in typical Irish fashion, I will answer your question with a question:

Why can't Matlab, etc., recognize the simple statement if 4 < t <= 7

Derek O'Connor.

PS: Another question: why is it so difficult to write anything but plain text on this site? I had to write | for the double |, which kept disappearing.

Anybody for Stack Exchange?

PPS: Yes, yes: we know how to get rid of all the elseif's

I am against it otherwise I would forget, and beginners wouldn't ever notice that:

for x positive (and e1,...eN monotonically increasing)
if x <= e1

elseif x <= e2.

elseif x <= e3

% and so on...

else (the N-th case)
end
end

@Derek: I do not understand "Boredom Forecast: High(78/100). Discussion of Syntax."
"4<t<=7" is not identical to "4<t && t<=7" if the expression t has side-effects. In addition it might be converted to "4<t & t<=7" also, or "and(4<t, t<=7)". This will affect the short-circuting in IF statements!
Although "4<t<=7" looks a little bit smarter, I could not be *frustrated* by such details.

@Jan,

Writing logical expressions with side effects is a mortal sin, especially in loop control. Such expressions have been the source of countless errors in the past and have been rightly deprecated by most experts.

Short-circuiting would not be affected if the compiler-interpreter does its job properly.

Everybody knows that MATLAB isn't even useful as manure, since you cannot write expressions such as

4 < t1 < t2 <= t3 < t4 < 11 <= t6 < 15

and have them interpreted way that would be obvious even to a 5th grader.

@Walter,

Your example vividly illustrates the old saying that "a good
programming language does not guarantee good programming".

Given the best programming language in the world, someone,
somewhere, will use it to write an expression such as yours.

As you indicate that most 1st or 2nd year computer science students could write a program that does the range translation, could you perhaps outline a BNF for such expressions allowing for indefinite comparison chaining? With a semantic description of what should happen if type conversions are involved? With smooth integration for operator overloading?

@Walter,

You are setting up "straw men". All I asked for was a simple
*syntactical* change that allows:

1st Form: if expr1 < scalar var < expr2

This would be translated during the lexical scan phase to:

2nd Form: if (expr1 < scalar var) && (scalar var < exp2)

So, if you and Jan have objections to the 1st form then these
apply equally to the 2nd form, which is valid Matlab. In other
words, the 1st Form introduces no *new* semantical problems.

Of course the vectorizers will object to "scalar var", but again,
that objection applies to both forms.

I have two reason for wanting the 1st Form:

1. Such expressions occur frequently enough to make this form
useful.

2. The more important reason is that the 1st Form is often
mis-translated by programmers, especially beginners.

Your second reason argues instead for an m-lint warning and fix-up.

You have restricted the scope to "scalar variables", but of course MATLAB is runtime sized, so it might not be known until execution whether your t is scalar or vector. If it is vector, then using && is a faulty translation. If you are going to admit the syntax, is there a reason why it should not be applicable to vectors and matrices?

If your t involves a function call, then it becomes important as to how many times t is evaluated. You *know* that people are going to code things like

if 0 <= f(x) <= 10

and you know that saying that it is bad practice is not going to deter them from doing so. So you need to define the semantics. Is it *just* a rewriting to save a few keystrokes, or is it an implicit evaluation with assignment to a hidden temporary variable that is deleted at the end of the clause? The choice is going to matter, especially when it comes to operator overloading.

What if the endpoints involve function calls? f(x) < 5 < f(y) for example. If it is just a rewriting then you don't know ahead of time whether f(y) is going to be executed. That's bad language design.

Side effects happen. For example *all* I/O involves side effects.

I don't believe in designing in syntactic sugar that has ill-defined meaning.

@Walter,

I can only repeat what I said above: " the 1st Form introduces no *NEW* semantical problems.

@Derek: So you want "a<b<=C" to be converted automatically to "a<b && b<=c", such that you do not get new problems, but no new features also. It would catch a frequent error of beginners, ok. And it would confuse the beginners in case of side-effects, because b is evaluated more often, than it appears in the code.
It is my opinion, that the confusion level is more dangerous than the buggy code and therefore I prefer a MLint warning - which should contain a hint to the vectorized approach based on HISTC.
But I see, that you'd prefer the "a<b<=c" syntax. Due to the fact, that this would change the current behaviour and millions or billions of lines of existing code had to be checked for incompatibilities, I do not assume, that this wish will be implemented.

If beginners should be pampered, remove EVAL, EVALIN, ASSIGNIN and the not-functional form of SAVE until the user confirms, that s/he will not be surprised to run into problems and will not ask corresponding questions in any forum.

@Jan

At least you concede that the "a<b<c" form would eliminate frequent
beginners' errors.

If beginners are using any logical expressions with side-effects
then they are already confused. The compiler-interpreter should
issue a warning and then tell them to stop programming and seek
professional help immediately.

How can the behavior of existing code be affected by "a<b<c" if, by
definition, that code has not used that form? That's like saying
that the handling of my 5-year-old Porche is going to change
because the 2011 model has a new suspension.

I take it from your final sentence that you do not like pampering
beginners. I wonder if teaching a class of 300 first-year Business
or Engineering students "An Introduction to Computers and
Programming" would change your mind?

I am not sure why you say that "by definition" existing code does not use the form "a<b<c" ? It is legal to use that code, and it has meaning in MATLAB. If a and b and c are logical variables, then a<b<c is equivalent to (a | ~b) & c which is true in 3 of the 8 logical conditions. Your proposed rewrite to (a<b) && (b<c) fails for non-scalars; if we change it to (a<b) & (b<c) to accommodate arrays, then the rewritten version is false for all 8 of the possible logical conditions. When working with logic variables, a < b is equivalent to (~a) & b, so b<c would be (~b) & c, and thus (a<b) & (b<c) would be equivalent to (~a) & b & (~b) & c; with the b & ~b you can see that the expression will always be false for logic variables.

Thus, you want to start with code that has defined and potentially useful meaning, and you want to make the code crash if it is used for non-scalars, and you want to define the new meaning to something that cannot possibly hold in some cases where the original meaning does hold. And yet this apparently will introduce no new semantic problems ???

Can we not at the very least have it as an axiom that introducing new syntactic sugar should not lead to errors in valid existing code?

@Derek: Currently working: 4<5<1 ==> FALSE, because this is (4<5)=TRUE and TRUE<1=FALSE. 4<5<2 ==> TRUE, because (4<5)=TRUE and TRUE<2=TRUE. I admit that this code is strange, but valid Matlab syntax. Therefore in this case pampering beginners would mean to affront the expert users.
I think it is clear, that I do not pamper beginners, but try to assist them to improve their Matlab skills. Fortunately I had the chance to teach much smaller classes in advanced numerical methods. To have enough time to concentrate on the essentials, I gave this crash course: "Read the FAQ, no EVAL, SAVE with parenthesis, LOAD with output, Matlab never acts magically."

@Jan, Walter

First we had straw men. Now we have red herrings:

>> for t = 3:8, if (4<t<=7),disp(['In Range']),else disp(['Out Range']),end, end

In Range In Range In Range In Range In Range In Range

>> for t = 3:8, if (4<t) && (t<=7),disp(['In Range']),else disp(['Out Range']),end, end

Out Range Out Range In Range In Range In Range Out Range

I can see that this discussion is leading nowhere, so let's end it
by agreeing to disagree.

Can we not at the very least have it as an axiom that introducing new syntactic sugar should not lead to errors in valid existing code?

@Walter: TMW follows this idea. At least usually. Some releases ago this was valid to reference a field of a struct directly after the function has return: "fcn(in).field". Now you need: "tmp = fcn(in), tmp.field". So I would not call it an axiom.

Answer 37

MATLAB assignment (a = 1) statements must be terminated with a ; to suppress output, but the 'natural' case is to NOT want output, in all but the simplest code segments (for me). As a result, my MATLAB code is cluttered with ;s, and I have the extra hassle of having to remember to put them everywhere. It seems that many have asked for this to be changed, but Mathworks has declined. I opine that it would an easy matter to allow either syntax via an inline flag or a global setting so that users have a choice. Then one could either change a setting in Preferences or add a line to one's code such as SemicolonOutputs=1 or SemicolonSuppresse=1. Dunno why it is so hard to convince Mathworks of that. I like the feature of being able to display results so easily without constructing a print statement, so I don't want the option to go completely away. ~R~

The ';' don't bother me -- I am accustomed to languages in which semicolons are statement separators or statement terminators. Often they serve to remove ambiguity when you have multiple statements on the same line.

I do not suffer from the semicolons. I've written programs in C, C++, Fortran77, Cobol, Basic (Sinclair and GFA), Maple, BodyLanguage (Vicon), Matlab, Perl, Tcl, Brainfuck and WhiteSpace. And my mother-language is German. Therefore a trailing semicolon is just another syntax detail - I _like_ them, if they are consistent and working.
I'm really happy that it is too hard to convince TMW to change such a fundamental detail.

On the other hand, if they weren't required and you put a semicolon only if you DID want the output echoed to the command window, I think I could adapt to that quite quickly. I don't string multiple commands together on one line - though more compact, I think that makes it confusing and harder to follow.

@IA: I do not include mutliple commands inside a line also, but there are is over a million of lines in the toolbox functions. Checking them in a 100% secure way will cost time and money. Some users create M-files dynamically, which is not cute, but existing. These functions would have to consider the current behaviour of the trailing semicolons.
I agree, that there is not good reason to use the semicolons. But there are very good reasons not to change the working syntax.

If TMW were starting from scratch, it might make sense to drop the semicolon, but I cannot see a reason to drop it now. I think the flag idea is really bad since it would introduce so many compatibility issues when sharing and reusing code.

I do wish mlint would give a warning for all lines that are not terminated with a semicolon: For example

x = 1:10
x
plot(x)

the plot function does not produce an mlint warning. This could cause nightmares if plot was changed to always return the handle.

@Walter, you can use commas to separate multiple commands on the same line (of course you get the output of each command).

According to an Answer from someone at Mathworks, the current version of timer interrupts can interrupt between any two lines -- which in turn means that if you have any critical code on a single processor or which is not protected by semaphores on multiple processors, then you should put the code on one line (and of course that code shouldn't call upon any toolboxes or .m or .p coded routines...)

Answer 38

The command editor is horrible: quaint and tedious and so frustrating to use. Compare it to the functionality present with GNU readline. Using the latter I can easily recall previous commands using quick keystrokes to search for commands containing a given string and quickly modify the command and execute it. In the matlab command editor you have ... the arrow keys. How quaint. Yes, you can type characters and hit the up arrow and recall earlier commands that started with that string. Be still my beating heart.

Answer 39

Fast simulation with S-Functions written in C. Speeding up simulation (e.g. in Accelerator mode) requires TLC files (at least wrapping). M-language requires full inlining (more TLC coding).

I haven't found any other way to enable rapid simulation with S-Functions and I don't want to code everything with Simulink Blocks (prefer S-Functions).

Maybe someone has a comment/hint on this?

Once wrote a function to convert an arbitrary mathematical function into a simulink block diagram. Maybe thats something for you?

Hey, thanks for your answer!
You mean putting Math Function and other blocks together?
This is what I actually don't like. My model is quite big, and I prefer writing it in M-Language (that's why S-Functions).

Hi Michael,

what about using the S-Function Builder? At least you get the tlc code for free ...

Titus

Answer 40

what frustrates me in MATLAB is how to make a graphic with continuous data which has two boundary conditions as a result from the previous formula. for an example

Lp=A+B;
Lr=C+D; % these are the boundary conditions
for Lb = 1:1:30 % this is the continuous data
  if 0<Lb<=Lp
      Mn(Lb) = E*F;
  elseif Lp < Lb && Lb <= Lr.
      Mn(Lb) = 0.5*((Lb-Lp)/(Lr-Lp))+F;
  elseif Lb>Lr
      Mn(Lb) = (Lb/3)^2 - (sqrt(Lb/G));
  end
end
plot(Lb,Mn)

what i wanted to make is that program running from the first condition to another. when the program is running the data until the first boundary condition, the data calculation must change into the second formula and so on. but if i use that script it didn't run like what i've wanted to be. what should i do to solve this kind of problems? thank you so much..

0<Lb<=Lp means (0<Lb)<=Lp, and (0<Lb) will be a logical result which is always 0 or 1. You need to code (0<Lb) && (Lb <= Lp)

hello Mr. walter thanks for your answer. so it means the logical is always based on Lb? Instead of the boundary Lp and Lr. one more question is it ok to use if-elseif above or i use a script just like this,

Mn=zeros(size(Lb));
idx1=0<lb && Lb<=Lp;
Mn(idx1)=Fy*Zx;
idx2=Lb>Lp & Lb<=Lr;
Mn(idx2)=Cb*((Fy*Zx)-(((Fy*Zx)-Mr)*((idx2-Lp)/(Lr-Lp))));
idx3=Lb>Lr;
Mn(idx3)=((Cb*pi)/idx3)*(sqrt((E*Iy*G*J)+(((pi*E)/idx3)^2)*Iy*Iw));
plot (Lb,Mn)

or

Mn=zeros(size(Lb));
[a,a] = histc(Lb,[-inf,Lp,Lr,inf]);
z = {@(x)Fy*Zx,@(x)Cb*((Fy*Zx)-(((Fy*Zx)-Mr)*((x-Lp)/(Lr-Lp)))),@(x)((Cb*pi)/x)*(sqrt((E*Iy*G*J)+(((pi*E)/x)^2)*Iy*Iw))};
out = arrayfun(@(x)z{x}(Lb(a==x)),1:3,'un',0);
y = [out{:}];

what's the difference between the first script and the second one?
thanks again Mr. walter
and happy new year..

I would say that the second of those is unnecessarily complex. It is clever, but difficult to read or maintain.

MATLAB programmers in general understand logical indexing, and understand "for" loops.

Usually logical indexing is faster than "for", but not always, especially not with R2010b or later, and not when memory is low.

I do not think I understand your question about whether the logic is based on Lb. No matter what variables are involved if you have X followed by a relation operator followed by Y followed by a relation operator followed by Z, the operations will be handled left to right, doing the test between X and Y first to create a logical value and then using that logical value in the comparison with Z. MATLAB does not have any built-in range comparison syntax such as you probably wanted to imply by 0<Lb<=Lp

Answer 41

all matlab information i've read about robot modelling in simulink 3D animation is all about serial robots and im working with parallel robots u.u

Answer 42

I dont know if somebody has posted this already but I would like to mention that the auto-fill feature frustrates me a lot. I can start out with a capital L looking for say "Lambda" it still shows me list of all the other things that start-out with "l". Come on MTW, there it cannot be that difficult to sort with case!

TMW or MTV?

Answer 43

The behaviour of pcolor: Why are the last column and row not shown? Why does the datatip always shows 0 for the z-coordinate?

Chess is played on the "faces" of the 8 x 8 grid, but Go is played on the intersections of that grid. Neither is right or wrong; they just are.

If you want a full-sized color display grid, use image() or imagesc() instead of pcolor().

If you want non-zero z-coordinates but interpolation at the intersections like for pcolor, then use surf() and view() it from the above.

pcolor() is intended to create a 2D pseudo-colored object, just the same way that image() creates a 2D object.

Answer 44

Lack of support for DAQ module digital IO when using 64 bit matlab. Yes, the obvious solution is to uninstall the 64 bit and install the 32 bit... Of course, I have machines deployed off site which need to run this code, but have the 64 bit loaded... argh..

the whole daq toolbox is pretty frustrating. Not sure why they need to change the way the code works, converting my code is going to be a pain when they finally finish the session based architecture. The old way works pretty well, don't think it should go away. And the lack of 64 bit support is baffling to me.

Answer 45

the constant version change and the no support for previous version commands

Mathworks normally keeps command compatibility for a number of years -- four to five in my experience.

Version change is the modern business reality: software which does not update often "enough" is considered to be too rigid and stodgy, and the company involved is seen to be "not agile enough" to react to changing market demands. People would migrate to other software.

I cannot, though, speak to Mathwork's policy on bug fixes. Some of the other vendors I deal with, do tend to put out "dot releases" to address the more important (or more frustrating) bugs between releases.

If you don't want to upgrade versions twice a year, don't. No one is forcing you to. They typically will say for years beforehand that a particular function is deprecated (meaning obsolete, scheduled for removal, and recommending/warning you not to use it). I know they changed roipoly but kept the old roipoly as roipolyold and deprecated it, but thankfully they've kept it so far (about 5 years or so). It has some nice features the new one doesn't have (yet). So the support will last for many years after you were warned not to use a function.

@Lucas, in the FOSS community (not that MATLAB is part of that) biannual time based releases are pretty common with Ubuntu, KDE, and LibreOffice all doing releases twice a year. Just because a new release comes out every 6 months doesn't mean you need to upgrade immediately. I generally am a year or more behind.

Answer 46

The number of MATLAB users using old versions who cannot cope with code written for new versions frustrates me. It would be easier if the MATLAB documentation made it easier to realize that using ~ to ignore input/output arguments is relatively new. Similarly, that the random number generator seems to be improved every year. Maybe adding updates to the documentation which explain what features are missing in the old release would convince people to upgrade.

I remember that somewhere in the forum somebody (Matt Fig or Jan Simon or both?) pointed out the need for a log of changes to the function inside the .m file (as we do in the FEX).

Unfortunately updating the documentation would only marginally improve productivity while requiring huge effort and time. However, TMW made older docs available on the web.

Even in simulink many additions and chagnes are done in each release but it is very difficult to trace which addition/change has introduced in which release :-(

TAB, have you ever read the release notes: http://www.mathworks.com/help/base/relnotes/? If these don't meet your needs, say why not.

@Oleg, it is not really that. I include change logs to my functions. If I write a new function the change log is empty. The documentation will say it was tested with r2011a (I tend to run a few versions behind). I will then get complaints that is doesn't work on r2009a.

Answer 47

My biggest Gripe is that it has not decent method of binary manipulation. Creat a bin data type that will display the answer in 1's and 0's without throwing it into a string. Tell me what the binary number looks like. Create a binary toolbox that is designed for firmware and embedded systems people like me. Please!!

Answer 48

Error messages like this one really frustrates me

    Error while evaluating TimerFcn for timer 'test4ida_timer'     
    Undefined function or variable 'parent_folder'.

The callback function of the timer invokes thousands of line of code. I feel Matlab lets me down: no function name, no line number.

It might not be the first time I complain about this. I reckon, it's my number one "Frustration cause candidate".

This one is even more frustrating

    Error while evaluating TimerFcn for timer 'test4ida_timer'     
    Specified key type does not match the type expected for this container.

This is a messy problem and I have a bug report/service request dealing with this and a partial solution. Care to post it as a new question?

And Per, please contact us as well to provide your specific feedback. I certainly agree, debugging with timers can be difficult.

Answer 49

Things that frustrate me about MATLAB... most problems usually revolve around Simulink.

1.) The Simulink 'model' command does not accept complex data types. The 'sim' command does...the model command is array inputs only.

2.) Simulink often initializes super slow when executing sim commands.

3.) If you tell Simulink to not recompile your model by 'assuming up to date', if you dont also set the "error if out of date" field to none, then it still will check whether the project is up to date.

4.) Simulink's performance advisor and profiler are a joke. Simulink profiler will tell you information, but you cant do anything with that information.

5.) It amazes me MATLAB still does not allow for writing out symbolic math easily.

6.) GUI's are trick y to put together. It seems like GUIDE is an all or nothing approach. You eather start your GUI from GUID or your start from scratch. Once you started a GUIDE project through, its very difficult to continue as a .fig only file.

When you refer to "writing out symbolic math", are you referring to input or output? As you familiar with MuPAD and MuPAD notebooks?