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I'm using UNIX platform whihc has MATLAB 2007b. My MPI FORTRAN calls MATLAB to use function "pwelch".
I'm getting following error :
*********************************************************************
terminate called after throwing an instance of 'MathWorks::System::SimpleException'
ERROR:engPutVariable
rank 5 in job 1 orville18.local_39792 caused collective abort of all ranks
exit status of rank 5: return code 0
*********************************************************************
What does it mean?(memory related problem?)
How do i solve it,any idea?
Thanks in advance...





I'm running Visual Studio 8 and Matlab 7, now I've changed matlab.h to matrix.h, which allows it to compile properly, however when it tries to build it can't open "libmatlb.lib". As I understand it MatLab 7 doesn't require libmatlb.lib or libmmfile.lib, but when I take out the code that tries calling them I get 8 more build errors:
Matlab to C++.obj : error LNK2001: unresolved external symbol "public: virtual __thiscall CMatlabEng::~CMatlabEng(void)" (??1CMatlabEng@@UAE@XZ)
Matlab to C++.obj : error LNK2001: unresolved external symbol "public: int __thiscall CMatlabEng::Close(void)" (?Close@CMatlabEng@@QAEHXZ)
Matlab to C++.obj : error LNK2001: unresolved external symbol "public: int __thiscall CMatlabEng::EvalString(char const *)" (?EvalString@CMatlabEng@@QAEHPBD@Z)
Matlab to C++.obj : error LNK2001: unresolved external symbol "public: int __thiscall CMatlabEng::PutVariable(char const *,struct mxArray_tag const *)" (?PutVariable@CMatlabEng@@QAEHPBDPBUmxArray_tag@@@Z)
Matlab to C++.obj : error LNK2001: unresolved external symbol "public: int __thiscall CMatlabEng::SetVisible(bool)" (?SetVisible@CMatlabEng@@QAEH_N@Z)
Matlab to C++.obj : error LNK2001: unresolved external symbol "public: void __thiscall CMatlabEng::Open(char const *)" (?Open@CMatlabEng@@QAEXPBD@Z)
Matlab to C++.obj : error LNK2001: unresolved external symbol "public: __thiscall CMatlabEng::CMatlabEng(void)" (??0CMatlabEng@@QAE@XZ)
Debug/Matlab to C++.exe : fatal error LNK1120: 7 unresolved externals
Error executing link.exe.
Any ideas on how to get over this obstacle?
thanks for your time
TNT





I have exactly the same problem, if you already fixed it, please let me know.
thanks,
gvallemoura





hi, i have read the article about how to use matlab syntax in c++, but i cant understand it(maybe its because my english is not good enough).
actually, i want to do singular value decomposition(svd) function from matlab to my c++ project because i dont want to waste time to make the function myself..(actually i need some functions, not only svd)
anyone can tell me step by step how to use/connect matlab in c++?
u can send me an email to rifsolution@yahoo.com
please help me..
thanx..
btw, i use matlab 5.3, msvc++ 6.0, windows vista





Dir Sir,
I use Microsoft Visual Studio.NET, Matlab 6.5. I tried to use header flie "engine.h", but I meet the below problem:
This is my code:

#include
#include
#include "engine.h"
void main()
{
Engine* ep;
ep = engOpen(NULL); // Connect to MATLAB engine

When I build project, I have the error:
error LNK2019: unresolved external symbol engOpen referenced in function_main
I look forward to hearing from you.
Thanks you so much.
Best regards,





Hi,
I have tried to run this code in visual studio 2005. I have changed Matlab.h to matrix.h, removed the unnecessary libs and the program compiles without error. However, at runtime I get an unhandled exception and a crash in gs_support.c in the lines listed below
#else /* defined (_WIN64) */
cookie = systime.ft_struct.dwLowDateTime;
cookie ^= systime.ft_struct.dwHighDateTime;
#endif /* defined (_WIN64) */
Please find error log below
'MatlabClass.exe': Loaded 'C:\Documents and Settings\mdp28\Desktop\MatlabEng_demo\Debug\MatlabClass.exe', Symbols loaded.
'MatlabClass.exe': Loaded 'C:\WINDOWS\system32\ntdll.dll', No symbols loaded.
'MatlabClass.exe': Loaded 'C:\WINDOWS\system32\kernel32.dll', No symbols loaded.
Firstchance exception at 0x000a4ad6 in MatlabClass.exe: 0xC0000005: Access violation reading location 0x000a4ad6.
Unhandled exception at 0x000a4ad6 in MatlabClass.exe: 0xC0000005: Access violation reading location 0x000a4ad6.
The program '[3800] MatlabClass.exe: Native' has exited with code 0 (0x0).
Regards
Michael





Hi,
at first thanks for writing CMatlabEng.
I want to use an instance 'm_matlab' of CMatlabEng as a member in another class.
I wanted to open the Instance in the constructor (m_matlab.Open(NULL);) and close it in destructor. I found out that it only works when Opening 'm_matlab' in the same method where I want to use it.
Do you have some idea what´s the reason for this?
thanks in advance Jower
jower





Hello!
Sounds familiar ... It seems the matlab engine can only be used within the same thread it's been initialized in. If your constructor is called within thread A and your actual data processing is done in another thread B, it won't work. (Check "GetCurrentThreadId()")
Its no solution but that's what I've figured out by now.
Best regards
Sven





I am using the MATLAB v7.0.0(R14)and changed "Matlab.h" to "Matrix.h".
But, when I have complied the "MatlabClass", I got the error message "cannot open file "libeng.lib" ".
Do I have to set the full path of "libeng.lib" in the "pragma comment(lib,HERE)"?
If it is right, please let me know where libeng.lib is.
Also, I couldn't find both "libmatlb.lib" and "libmmfile.lib" in the whole matlab folder.
thank you
best regards,





Maybe you didn't install MATLAB Compiler Toolbox.
A. Riazi





You don't need libmatlb.lib or libmmfile.lib anymore for Matlab 7.0, so get rid of those. I don't know how to help you with libeng.lib, though.
Good luck.





How do you get the values from the pointer? (I'm new at C++.)
I do this:
mxArray *myP;
myP = mxCreateDoubleMatrix(1, 1, mxREAL);
int inMyP[1][1];
memcpy((void*) mxGetPr(myP), (void*) inMyP, sizeof(inMyP));
matlab.PutVariable("myP", myP);
matlab.EvalString("myP=1;");
myP = matlab.GetVariable("myP");
cout << myP << endl;
But myP isn't 1.
Thanks.





You created a double matrix: mxCreateDoubleMatrix(....)
but declared an integer array: int inMyP[1][1];
change this line to double inMyP[1][1];
Best regards,
A. Riazi





Yay! I got it to work. This is the code, slightly modified from above. The way to fix it is to use the memcpy function, but flip the variables.
mxArray *myP = NULL;
myP = mxCreateDoubleMatrix(1, 1, mxREAL);
double inMyP[1][1];
//matlab.PutVariable("myP", myP); //Don't need.
matlab.EvalString("myP = 1");
myP = matlab.GetVariable("myP");
memcpy((void*) inMyP, (void*) mxGetPr(myP), sizeof(inMyP)); //This was the fix, notice that the variables are changed around.
cout << inMyP[0][0] << endl;
cout << endl;
mxDestroyArray(myP);
Thanks a bunch for your help.
 modified at 16:09 Wednesday 10th January, 2007





myP is a pointer to mxArray structure. Then by using
cout << myP << endl;
you will see address of pointer. For printing the content of the matrix, use mlfPrintMatrix() function.
Here is the code:
mxArray *A;
A=mxCreateDoubleMatrix(3, 3, mxREAL);
memcpy(mxGetPr(A), (void *) imMyP, 3 * 3 * sizeof(double));
mlfPrintMatrix(A);
For more info, please see my other article: Solving Engineering Problems Using MATLAB C API[^]
Best regards,
A. Riazi





Great! I might use this in the future for dealing with larger arrays.
Clement





I'm currently using MATLAB version 7.3.0.267(R2006b)
 modified at 14:58 Friday 1st December, 2006





You may change matlab.h to matrix.h, and it works. Good luck!
Prgramming





In fact, neither "matlab.h" nor "matrix.h" is needed to run this demo in Matlab 7.0! Also, "libmatlb.lib" and "libmmfile.lib" should be removed.





Plz email me if you could find the answer also
I find the following error
#include"engine.h" not found





Dear Riazi,
I'm currently building a C++ project and hoping to use the MATLAB ploting function to show the results. I already loaded your code into the project folder but there seems to be a runtime error, for example, "...undefined reference to CMatlabEng::CMatlabEng()..." I think my problem is how to intergrate/compile your code with mine. In other words, I don't know how to put your code into my makefile.
Please, Riazi, if you have any suggestion or know of any way to make this work, please help.
Thank you very much.
Nik.





As I know, MATLAB Engin API only works under windows. Because the API uses Automation (ActiveX) technology.
Best regards,
A. Riazi





can you tell me how to embed the matlab figure into winform,like list control?
i use microsoft vc#2003 and matlab r2006a.
thank you very much.
tom





Hi, I need call some functions of the Intel Library OpenCV from matlab.I'm doing a project with matlab about image processing. My project director told me that there was a direct form for call this Intel library but now it's not possible.then, I'm thinking do it by a MEXfiles and need help!!!
How can I do it?
Thank you very much!!!!
Pedro Fernandez.





There are two ways:
1 Writing your own MEX files.
2 Create an ActiveX control containing the OpenCV codes then using the control inside your mfiles.
Best regards,
A. Riazi







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