topic in Intel® oneAPI Math Kernel Library

For what reasons can mkl_free() fail?

Po — Fri, 23 Aug 2013 23:05:48 GMT

I am working with Intel's MKL in C++ and I get a lot of runtime errors with themkl_free(some_matrix); call. Usually, it just hangs when it reaches the matrix. What are the reasons that can cause it to fail?

>>...the mkl_free( some

SergeyKostrov — Sun, 25 Aug 2013 19:22:49 GMT

>>...the mkl_free( some_matrix ) It is not enough and more technical details are needed. >>...What are the reasons that can cause it to fail? Please provide an example of how you use MKL functions.

Thanks for your reply Sergey.

Po — Sun, 25 Aug 2013 22:38:03 GMT

Thanks for your reply Sergey. I am using MS Visual Studio 2008 to build with MKL 11.0.5. When I run the application in Release mode, the program simply hangs so I was looking for ideas on how to debug the issue. A sample of the mkl_free() call can be found here on line 1464:

https://github.com/poliu2s/MKL/blob/master/MultiObjModelToUSReg/OptimizeShapeAndPoseCoef.cpp#L1464

Could you please prepare the

Gennady_F_Intel — Mon, 26 Aug 2013 06:53:50 GMT

Could you please prepare the standalone example shows the problem? the example you provided cannot be compiled.

Could you comment everything

SergeyKostrov — Tue, 27 Aug 2013 04:26:31 GMT

Could you comment everything between these two blocks in order to very that simple allocation-deallocation works without any problems? void Registration::multiObjectAtlasShapeCoefFunction( ... ) { ... // Initialize some variables double* Tr = (double*)mkl_malloc(4 * 4 * sizeof(double), 64); double* Tr2 = (double*)mkl_malloc(4 * 4 * sizeof(double), 64); ... /* Comment all codes between allocations and deallocations */ ... cout << "Before free" << endl; // Free all local variables mkl_free_buffers(); cout << "a" << endl; mkl_free(Tr); // fails to free cout << "b" << endl; mkl_free(Tr2); // cout << "c" << endl; // mkl_free(pose_feature_transform); // cout << "d" << endl; // mkl_free(pose_feature_transform2); // cout << "e" << endl; // mkl_free(ones); // cout << "f" << endl; // mkl_free(part1); // cout << "g" << endl; // mkl_free(part2); // cout << "h" << endl; // mkl_free(part1_2); // cout << "done." << endl; } Then, start uncommenting line-by-line with verifications of binaries ( in Debug and Release configurations ) until you reproduce the problem. If you manage to reproduce it follow these simple steps a last uncommented piece of codes is where the problem is.

DarioMangoni — Wed, 28 Oct 2015 17:06:01 GMT

Sergey Kostrov wrote:

>>...the mkl_free( some_matrix )

It is not enough and more technical details are needed.

>>...What are the reasons that can cause it to fail?

Please provide an example of how you use MKL functions.

Hi Sergey,
I revive this old post because I have some problems with mkl_free that throws exceptions and I disagree with your answers.
Compared to all of you I'm a ultra-novice programmer, but I heard that, if I have to write a function/method, I have two choices:
1 - make it exception free
2 - don't make it exception free
If 1 applies then we would be all happy.
If 2 applies I have two choices:
2a - my software is open-source and I don't want to support any user that would use my library/program. I could say:
"An exception is thrown? P**s off, and give a look at the definition yourself"
2b - my software is closed, I sell it, I make a lot of money and just because of this I provide a rich documentation about every single exception that can be thrown.
No matter "how you use MKL functions", no matter about "technical details" of the end-user program.
It's true: at 99% the user is wrong. He misused the function, he messed up everything, etc... but let him discover his own mistakes ! Let him debug his own code! Don't give him bread. Give him the tools needed to grow wheat.

Having said that, I might be wrong and if so I'm sorry, but if not, please think about it.