I recently found out that you can get Octave to warn when you are using features not compatible with Matlab. Due to working with others this feature is appealing.
warning ('on', 'Octave:matlab-incompatible')
However when I use it in even simple scripts
warning ('on', 'Octave:matlab-incompatible');
x = 5;
plot(x);
I get many warning due to the implementation of plot using non-Matlab compatible features. For example
warning: potential Matlab compatibility problem: ! used as operator near line 215 offile /usr/share/octave/3.8.1/m/plot/draw/plot.m
Is there a way to turn off these warnings? I don't care if plot is implemented using non-Matlab features because when I use Matlab its implementation will be fine.
No that is not possible which makes the Octave:matlab-incompatible almost useless. Also, that warning is only printed for syntax so you can still use Octave only functions (such as center or sumsq) without any problem.
I recommend you use a text editor that has separate Matlab and Octave syntax highlight (such as gedit) and avoid things that don't get highlighted.
Here's how it's done in Matlab, which looks to be similar to the Octave case:
warning('on', 'Octave:matlab-incompatible'); % Your Octave warning
x = 5;
WarnState = warning('off', 'Offending_MSGID'); % You'll need to get the specific ID
plot(x);
warning(WarnState); % Restore
Yes, it's a bit clumsy. There's no way to specify that a warning is not enabled within a particular file that I know of.
One thing that can happen is that the code an be interrupted by the user or an error before the warning state is restored. In this case, Your system now is in an unknown warning state. One way to avoid this is to use onCleanup. This function is called when a function exits, even if it exits due to an error. You might rewrite the above as:
warning('on', 'Octave:matlab-incompatible'); % Your Octave warning
x = 5;
WarnState = warning('off', 'Offending_MSGID'); % You'll need to get the specific ID
C = onCleanup(#()warning(WarnState));
plot(x);
...
Note that onCleanup won't be called until the function exits so the warning state won't be restored until then. You should be able to add a warning(WarnState); line to manually restore before if you want. Just be sure that whatever function onCleanup is calling can never return an error itself.
Related
In the Dymola translation log of one large model I see several times the warning:
Warning: Can only compute non-scalar gradients of functions specifying derivatives and not for:
noEvent
with no indication of where it comes from. Could someone explain what the warning means, and how to find and fix it?
Any message of that kind should only occur if you have set the flag Advanced.PrintFailureToDifferentiate = true; if you set this flag to false it should not occur.
The likely cause is that you have a non-scalar expression involving noEvent that for some reason needs to be solved using a system of equations; and it just means that Dymola does not yet generate analytic Jacobians for such systems.
The exact cause is difficult to say without the model; you could send that through the normal support-channels.
So I'm doing some hobby-related stuff which involves taking Fourier transforms of large real arrays which barely fit in memory, and was curious to see if there was an in-place version of rfft and irfft that saved RAM, since RAM consumption is important to me. These transforms are possible despite the input-vs-output-type mismatch, and require an extra row of padding.
In Implement in-place rfft! and irfft!, Tim Holy said he was working on an in-place rfft! and irfft! that made use of a buffer-containing RCpair object, but then Steven Johnson said that he was implementing something equivalent using A_mul_B!(y, plan, x), which he elaborated on here.
Things get a little weird from then on. In the documentation for both 0.3.0 and 0.4.0 there is no mention of A_mul_B!, although A_mul_B is listed. But when I try entering them into Julia, I get
A_mul_B!
A_mul_B! (generic function with 28 methods)
A_mul_B
ERROR: A_mul_B not defined
which suggests that the situation is actually the opposite of what the documentation currently describes.
So since A_mul_B! seems to exist, but isn't documented anywhere, I tried to guess how to test it in-place as follows:
A = rand(Float32, 10, 10);
p = plan_rfft(A);
A_mul_B!(A,p,A)
which resulted in
ERROR: `A_mul_B!` has no method matching A_mul_B!(::Array{Float32,2}, ::Function, ::Array{Float32,2})
So...
Are in-place real FFTs still a work in progress? Or am I using A_mul_B! wrong?
Is there a mismatch between the 0.3.0 documentation and 0.3.0's function library?
That pull request from Steven Johnson is listed as open, not merged; that means the work hasn't been finished yet. The one from me is closed, but if you want the code you can grab it by clicking on the commits.
The docs indeed omit mention of A_mul_B!. A_mul_B is equivalent to A*B, and so isn't exported independently now. A_mul_B! would be used like this: instead of C = A*B, you could say A_mul_B!(C, A, B).
Can you please edit the docs to fix these issues? (You can edit files here in your webbrowser.)
There is a nice command in Matlab called hold all, which causes subsequent plot commands to add to the current plot, using subsequent colours from the current colourmap.
But Octave says:
o.exe:248> hold all
error: hold: invalid hold state
error: called from:
error: C:\Programs\Octave\324_gcc440\share\octave\3.2.4\m\plot\hold.m at line 70, column 2
I've been using hold on, but all the lines a blue and similar, and I'm finding I'm spending too much brainpower trying to figure out which is which, rather than focus on understanding the pattern.
I'm looking for a solution that I can just type in, would rather not modify Octave's code or add scripts, for all the obvious reasons. Automatic colourmap rotation ought to have been the default behaviour, so maybe I'm missing something obvious...?
The option hold all already exists in Octave. The problem is that you're using a very old version of Octave. The current version is 3.6.4.
Sometimes I accidentally declare variables that have the name of a function.
Here is a constructed example:
max(4:5) % 5
max(1:10)=10*ones(10,1); % oops, should be == instead of =
max(4:5) % [10 10]
At the moment I always find this out the hard way and it especially happens with function names that I don't use frequently.
Is there any way to let matlab give a warning about this? It would be ideal to see this on the right hand side of the screen with the other warnings, but I am open to other suggestions.
Since Matlab allows you to overload built-in functionality, you will not receive any warnings when using existing names.
There are, however, a few tricks to minimize the risk of overloading existing functions:
Use explicitFunctionNames. It is much less likely that there is a function maxIndex instead of max.
Use the "Tab"-key often. Matlab will auto-complete functions on the path (as well as variables that you've declared previously). Thus, if the variable auto-completes, it already exists. In case you don't remember whether it's also a function, hit "F1" to see whether there exists a help page for it.
Use functions rather than scripts, so that "mis-"assigned variables in the workspace won't mess up your code.
I'm pretty sure mlint can also check for that.
Generally I would wrap code into functions as much as possible. That way the range of such an override is limited to the scope of the function - so no lasting problems, besides the accidental assumption of course.
When in doubt, check:
exist max
ans =
5
Looking at help exist, you can see that "max" is a function, and shouldn't be assigned as a variable.
>> help exist
exist Check if variables or functions are defined.
exist('A') returns:
0 if A does not exist
1 if A is a variable in the workspace
2 if A is an M-file on MATLAB's search path. It also returns 2 when
A is the full pathname to a file or when A is the name of an
ordinary file on MATLAB's search path
3 if A is a MEX-file on MATLAB's search path
4 if A is a MDL-file on MATLAB's search path
5 if A is a built-in MATLAB function
6 if A is a P-file on MATLAB's search path
7 if A is a directory
8 if A is a class (exist returns 0 for Java classes if you
start MATLAB with the -nojvm option.)
I have a problem involving NDSolve in Mathematica, which I run multiple times with different values of the parameters. For some of these values, the solution results in singularities and NDSolve warns with NDSolve::ndsz or other related warnings.
I would simply like to catch these warnings, suppress their display, and just keep track of the fact that a problem occurred for these particular values of the parameters. I thought of the following options (neither of which really do the trick):
I know I can determine whether a command has resulted in a warning or error by using Check. However, that will still display the warning. If I turn it off with Off the Check fails to report the warning too.
It is possible to stop NDSolve using the EventLocator method, so I could check for very large values of the function or its derivatives and stop evaluation in that case. However, in practice, this still produces warnings from time to time, presumably because the step size can sometimes be so large that the NDSolve warning triggers before my Event has taken place.
Any other suggestions?
If you wrap the Check with Quiet then I believe that everything should work as you want. For example, you can suppress the specific message Power::indet
In[1]:= Quiet[Check[0^0,err,Power::indet],Power::indet]
Out[1]= err
but other messages are still displayed
In[2]:= Quiet[Check[Sin[x,y],err,Power::indet],Power::indet]
During evaluation of In[2]:= Sin::argx: Sin called with 2 arguments; 1 argument is expected. >>
Out[2]= Sin[x,y]
Using Quiet and Check together works:
Quiet[Check[Table[1/Sin[x], {x, 0, \[Pi], \[Pi]}], $Failed]]
Perhaps you wish to redirect messages? This is copied almost verbatim from that page.
stream = OpenWrite["msgtemp.txt"];
$Messages = {stream};
1/0
FilePrint["msgtemp.txt"]