I am trying to execute some example code from a MATLAB toolkit, 'oscmex'. This toolkit allows for communication using the OSC protocol over MATLAB. I presume this question is non-specific; it should apply to any toolkit that is set-up in the manner that this one is.
Reasons aside, I'm having some simple trouble getting the toolkit up and running. The toolkit comes with no documentation whatsoever; just a set of six DLL files (in one directory), and a set of four MATLAB '.m' example code files (in another directory). Every toolkit I've used in the past has either been a built-in kit or has had an intuitive (semi-automated) install procedure.
After downloading the toolkit, the first thing I tried was to simply run one of the '.M' example codes. This failed as the first line of the code contained the function osc(), which is not (currently) recognised by MATLAB.
So, I figured maybe I need to move the '.M' files into the same folder as the DLLs; perhaps MATLAB would see the functions inside the DLLs. No dice.
So, I realise that I have to somehow link MATLAB to the DLLs on startup. I tried adding the DLLs to a folder and adding an entry to that in the 'pathdef.m' file. This also failed.
I've read somewhere I can load a DLL file by using the loadlibrary() function. So, I tried doing this for the DLL files. This failed on the first file:
>> loadlibrary('osc_free_address.dll')
Error using loadlibrary>lFullPath (line 587)
Could not find file osc_free_address.h.
I'm starting to run out of options... How can I get this set of DLLs up and running?
Browsing this library's web page it would seems these DLLs are just old form of mex files.
Therefore, they should not be used in the context of shared library (e.g., using loadlibrary and calllib), but rather compiled directly to mex files.
To do so, I would suggest the following steps:
Make sure you have a working mex compiler configured for your Matlab.
In matlab, type:
>> mex -setup
this will guide you through the configuration process. I understand that you are working on a windows machine, I usually work with visual studio compiler - works best for me.
This library's README file suggests that OSC
requires liblo 0.22 or later. See http://plugin.org.uk/liblo/
Make sure you have this library and it is located in you LD_LIBRARY_PATH (see e.g., this question for details, or the mex docs).
Get the source code for OSC library from their repository.
Compile the sources in matlab using
>> mex -O -largeArrayDims osc_free_address.c
>> mex -O -largeArrayDims osc_free_server.c
and so on for all 7 c source files. After mex-ing the c files you'll have mex files that you can run from Matlab as if they were regular functions.
You may find it useful to use the library's make file, as suggested by Andrew Mao.
Good luck,
If you look at the build for that software, it is compiling mex files, not DLLs (shared libraries): http://sourceforge.net/p/oscmex/code/4/tree/trunk/src/osc_make.m.
I would try using the mex commands instead of the dll commands (perhaps the files are just misnamed.) Even better, I would compile the files yourself with mex using the build file in source.
Note that the instructions also say that you need liblo-0.22 in order to run the library, so make sure you have that accessible as well.
I took a look at your OSC Toolkit. It seems they have been compiled by MATLAB mex. But, it is not mentioned for which kind of architecture they have been built. You can type mexext at MATLAB command prompt to find the extension for your MATLAB mex files. Then, change the DLL extensions to the given extension. If the original mex is compatible with your matlab, the DLL can be easily accessed by MATLAB. Just make sure to add the folder to your MATLAB path.
Try changing the extension from .dll to .mexw32 (in win32), or .wexw64 (in win64). It's a long shot but it might work.
The Shared Libraries cannot be used directly. As you have mentioned, you need to load them into MATLAB using loadlibrary. According to the documentation, loadlibrary takes two arguments (at least). The first argument is the name of the file, and the second one is the header file which contains definition of functions and external variables. If you do not provide the header file, the MATLAB looks for the a file with the same name as the DLL. Having said that, you need to have access to the header file or at least if you know how the function looks like, you need to write a header for the DLL.
I have worked with the DLLs in MATLAB. The MATLAB is not very user-friendly as long as DLL is concerned. Especially, if the DLL is written in a language other than C (or C++) you will have trouble loading the function into MATLAB.
Besides, MATLAB can only support some specific DLLs. Based, on your version of MATLAB, you need to find out whether or not the shared library is supported by MATLAB. Have a look at Here
In a nutshell, it is not easy to load a DLL into MATLAB. You need to have some information from DLL.
Related
For a while I have been compiling some mex files with own CUDA functions. I have the nvcc set up and everything compiles, and runs without problems.
However, when compiling
mex -largeArrayDims ./Source/Atb.cpp ./Source/voxel_backprojection.cu ./Source/voxel_backprojection2.cu -outdir ./Mex_files
I always get the following messages after the successful compilation
Building with 'NVIDIA CUDA Compiler'.
Could Not Find C:\CUDA_MATLABtests\MyToolbox\Mex_files\Atb.exp
Could Not Find C:\CUDA_MATLABtests\MyToolbox\Mex_files\Atb.exp
Why do I get this messages, If the code seems to work properly?
Should I have them? If so, should I manually create them? How?
In Visual Studio, an export (.exp) file is created so that others can link against your library.
For your typical mex file, no one will be linking against it, therefore the .exp files are not necessary. This is why your mex file runs just fine despite the fact that MATLAB issues this warning. Their uselessness in the context of mex files is further verified by the fact MATLAB tries to delete them itself during the cleanup process.
del PATH/Atb.pbj PATH/Atb.exp PATH/atb.manufest
Since Visual Studio generates these files by default (and there doesn't seem to be a good way to disable this behavior), I believe that they should exist somewhere on your machine after your code is compiled. It may actually be that MATLAB's mex configuration doesn't properly handle where to place these files and they end up somewhere other than your output directory.
I don't have Visual Studio currently, but you could probably search your local machine for that .exp file just to verify that it is indeed created and it's just placed somewhere that MATLAB isn't expecting. If this is the case, you can likely tweak your mexopts to handle this.
That being said, this warning is harmless for your typical mex file and can safely be ignored.
MATLAB Answers post on the topic
I created a .mex file of a MATLAB file test.m from MATLAB R2012b using MATLAB coder.
I got the output file test_mex.mexa64. I was hoping to use this .mex file in MATLAB 7.5.0 (R2007b) but it shows the following error.
Invalid MEX-file '/work/sreekanthl/test_mex.mexa64': libmwblascompat32.so:
cannot open shared object file: No such file or directory.
How can I make this .mex file work in 7.5.0 (R2007b)?
I agree with David Kelley's answer for general MEX files but there is a special consideration for MATLAB Coder generated MEX files. MATLAB Coder generated MEX code is expected to be forward compatible but generally is not expected to be backward compatible. In other words, you are expected to be able to use such MEX code in a newer release than the one with which it was generated, however using the code in an earlier release cannot be guaranteed to work.
The reason for this is that the MEX code uses various runtime libraries which ship with MATLAB. These libraries advance over time and the MEX file from the newer version may depend on features that the older libraries do not provide, or even on a new library which does not exist in the older release as you are seeing here.
If you want to create MEX code that is compatible with earlier releases, you could generate a standalone target such as a static library or a shared library (LIB or DLL respectively for MATLAB Coder), and either:
Try to use loadlibrary to call the generated code in MATLAB
Write a generic MEX interface for it and compile that MEX code in the older release
These options are more work but should enable you to create a MEX file or shared library usable in an older release.
While TMW says that mex functions are usually compatible between versions, it's not officially supported and quite common to run into issues with it.
The only reliable option is to simply recompile the generated source code that Matlab coder created (i.e., the C code) in the version you want to run it in using the mex function.
can you give me a basic c++ code that inclue opencv libraries , and can call the matlab engine ?
the file should compile using matlab mex.
(my problem is when I use the engine and compile it with "mex -f optionfile file.cpp"I get error message "cannot include opencv\cv.h" , but using the opencv without the engine its work using the mex file.xpp)
You need Matlab engine if you want to run .m files outside of Matlab command window (e.g. bash, c++ source file, etc.)
In your case, mex program (Matlab External Interface which acts like g++ or other c++ compilers) is required to compile a c++ source file. You must provide mex program a source file which is written according to what Matlab has introduced in its documentation.
If your source code (.cpp file) is including opencv/cv.h file and using one of its methods, you need to link the appropriate library (say libopencv.so, libopencv.dll or etc,) using -l flag. (I use mex foo.cpp -l opencv_core)
I hope it helps, you can provide your source
I am trying to compile a C++ function (found here). I downloaded the requisite packages, installed Microsoft Windows SDK 7.1, linked it to MATLAB using mex -setup, and then unzipped the function packages into my MATLAB path.
When I run the command:
mex -output Faddeeva_w -O Faddeeva_w_mex.cc Faddeeva.cc
I get the error message:
C:\PROGRA~1\MATLAB\R2013A\BIN\MEX.PL: Error: 'Faddeeva_w_mex.cc' not found.
But if I type which Faddeeva_w_mex.cc I get:
C:\Users\craigim\Documents\Code\Matlab\Faddeeva-MATLAB\Faddeeva_w_mex.cc
So MATLAB and the which command have no problems finding the file, but mex is lost. This is my very first attempt at compiling something with mex, so I'm really not sure where to start here. Does mex have a different path variable that I have to set?
I'm using MATLAB 2013a on a Windows 7 64bit machine with the version of SDK 7.1 that was linked from the MATLAB List of supported compilers.
Either cd into the directory containing the files (assuming they both in the same place), or specify full/relative path to the C++ files when invoking mex function
Try putting addpath('C:\Users\craigim\Documents\Code\Matlab\Faddeeva-MATLAB\'); in your m-file. The path that MATLAB uses seems to be internal and independent of whatever your OS is using.
Documentation on addpath here.
And a similar discussion here.
You may also have to set your PATH environment variable to the string returned by the command fullfile(matlabroot,'bin',computer('arch')) in MATLAB. Here are some instructions on setting environment variables for Windows and Mac or Linux
There is also a pretty good overview of building mex-files here although I get the impression that the basics are not going to answer your question.
I have dowloaded libsvm from http://www.csie.ntu.edu.tw/~cjlin/libsvm/
I unziped and copied the libsvm folder to c:..../documents/MATLAB folder. includedmex.h to all C files. Inside libsvm-> I have different folders. also in that Matlab folder I have files like libsvmread.c , libsvmwrite.c , makefile, make.m, svmtrain ,svmpredict etc...
how I can use these files in matlab? Can any one help me to create .mex files for these files.
I read and tried many times ..it is not working correctly for me. I need to do svmensemble creation in matlab.can anyone help me ASAP.
Have a look at the README file:
Installation and Data Format
On Unix systems, type make' to build thesvm-train' and
`svm-predict' programs. Run them without arguments to show the usages
of them.
On other systems, consult Makefile' to build them (e.g., see
'Building Windows binaries' in this file) or use the pre-built
binaries (Windows binaries are in the directorywindows').
For more information, tell us which operating system you are using.
you need to do mex -setup to configure the compiler.After which, you run the make.m file in the matlab folder.. Please read the README file.. the details are there...