I have an m file from which I use to create dll using the Matlab deploytool. the code simply reads as:
function hello
disp('Hello')
end
there are six functions in the compiled dll exported as:
uint8 helloInitialize
[uint8, voidPtr, voidPtr] helloInitializeWithHandlers(voidPtr, voidPtr)
helloPrintStackTrace
helloTerminate
uint8 mlfHello
[uint8, MATLAB arrayPtr, MATLAB arrayPtr] mlxHello(int32, MATLAB arrayPtr, int32, MATLAB arrayPtr)
Now I want to run this dll from my matlab command window using calllib and use
the hello function. Assuming that I use the correct function mlfHello, calllib('hello','mlfHello') gives me nothing. Please advise me on what function to call and how to do it?
I'm not 100% its still the case but it certainly used to be that you couldn't load DLL's which were created in Matlab back into Matlab.
I suspect its still the case - so you cant do what your trying to do.
[edit] I dont have a link because they dont like to advertise the fact. The reason AFAIK is to avoid users compiling toolbox capability into DLL and giving to others to use in Matlab without a toolbox license.
Related
I am running my code in Matlab. But I also want to call a function in octave. How should I import the qp function of Octave to Matlab?
The Octave language is a superset of the Matlab language. If qp only made use of the Matlab language, then you could simply add it to your Matlab path and be done with it.
However, Octave's qp makes extensive use of Octave only language so you basically have to port the code yourself. There are no tools for this, you have to convert the code from one language to another. In addition, the actual solver is the function __qp__ which is written in C++ and uses liboctave.
Two easier alternatives than porting qp are:
save the data from your Matlab session into a file save foo.mat mydata, call Octave to do the work and save the results system ('octave --eval ''load ("foo.mat"); qp (...); save foo.mat ...;', and read the file back load foo.mat.
or the much simpler alternative, just use Octave.
Octave syntaxt is not totally compatible with MATLAB. For example the preferred syntax for defining function in Octave is like this:
function ret = f()
%do something
endfunction
but MATLAB doesn't accept that syntax and there are other differences like differences in calling native codes and ... so it is not simple to convert each statement of octave library to matlab or convert oct c++ source to mex.
A straightforward way is that you should have an installation of Octave and run octave script from it then save the results to a mat file and in MATLAB load the file . You may use system function to execute octave or run it from shell.
so lets say you have 2 files in the same directory. a.m and b.m In the script b.m if you type a as a line of code everything in a.m will happen (variable assignments function definitions computations etc...)
Additionally you can use the import statement for adding things to your import list. as seen here.
I tried using the .. command in MATLAB to generate Laguerre polynomials but I keep getting this error every time:
I found this in the help section:
Since I have defined x as symbolic I shouldn't be getting this error.
Also on website I found this which says that the function does not run in MATLAB.
Can anyone help? Thanks in advance
Like you say, and the matlab help says this function only works inside mupad, maybe in later versions it works in matlab console.
If you want to use it, write mupad in Matlab Command window and then use it in the mupad, matlab will return you the result as I show in the picture
In R2014b+, there is a laguerreL function available directly from within Matlab. However, a version of this function was introduced to MuPAD in R2009a. You can call the MuPAD version from within Matlab
syms x;
feval(symengine,'laguerreL',2,x)
or
evalin(symengine,'laguerreL(2,x)')
Both return x^2/2 - 2*x + 1.
You can read more about interacting with MuPAD functionality from Matlab here. However, I'd recommend browsing and searching the archived documentation for your specific version or using your built-in HTML documentation (e.g., doc mupad or doc 'calling mupad').
I need to write a MEX file to evaluate the double integral of an arbitrary function, since in Matlab the numerical integration is too slow.
So far I was only able defining by hand all the possible functions that I use and parse a string in the MEX file to choose which one to integrate. This is very ugly.
I would like to send to the MEX file directly the function, something like
myIntMex(#(x,y)f,0,1,0,1)
to integrate function f in the interval [0,1]x[0,1].
So far the only option I have found is mexCallMATLAB but I have also read that it is even slower than pure Matlab.
I have also found a free code here but it only works for single integrals.
So my question is: how do I do it? How do I give to the MEX file the function handle? Does a code for that already exists?
My teacher in the signal analysis course has given me some Matlab code that I have to execute in order to complete a home assignment. I have always been using GNU Octave without troubles, but this time there is this command that is giving me headaches.
[c8,g8]=fit(time, sin_4_harmonic,’fourier8’)
I cannot find the function "fit" in GNU Octave, which is referenced for Matlab at the following url http://www.mathworks.se/help/curvefit/fit.html
Does anyone knows which package should I load, or if there is any equivalent?
Thanks =)
As far as I know, that function is not present in any of the Octave packages. However, the best place to look for something similar would be the optim package, probably the function nonlin_curvefit. Looking at the documentation, the model fourier8 is of the type Y = a0+a1*cos(x*p)+b1*sin(x*p)... +a8*cos(8*x*p)+b8*sin(8*x*p).
A work-around may be using "polyfit" function. To get the values, use "polyval".
I want to know how can this function(from MATLAB) resize the columns of an input image using weights an indices previously computed.
Which equations uses to do that?
resizeColumnsCore(double(in), weights', indices');
When I looked for a function called resizeColumnsCore in MATLAB 7.11.0 (R2010b) I didn't find anything. However, I did find a MEX-file by that name in MATLAB 7.8.0 (R2009a) in this subdirectory of the Image Processing Toolbox:
C:\Program Files\MATLAB\R2009a\toolbox\images\images\private\
I guess they've phased it out or replaced it with another function in newer MATLAB versions. Now, if you want to know what the MEX-file does, you need to look at the source code it is compiled from. Luckily, it appears that this source code resizeColumnsCore.cpp can be found in the following directory:
C:\Program Files\MATLAB\R2009a\toolbox\images\images\private\src\misc\
And you can look through that code to determine the algorithms used to resize the columns of an image given a set of weights and indices.
Now, if you want to know how these input arguments to resizeColumnsCore are computed, you'll have to look at the code of a function that calls it. I know of at least one function in the IPT that calls this function: IMRESIZE. If you type edit imresize at the command prompt it will open that function in the Editor, allowing you to look through the code so you can see how the arguments to resizeColumnsCore are created.
What I can tell you for R2009a is that there is a subfunction in the file imresize.m called contributions which computes the weights and indices that are ultimately passed as arguments to resizeColumnsCore. That is where you will want to start looking to determine what algorithms are used to compute these arguments.
Looks like this isn't a proprietary MATLAB function. Could we see some code or a link to the code?