Known Limitations in MKL 10.1 - For Windows*


Limitations to the FFT functions:

  • Mode DFTI_TRANSPOSE is implemented only for the default case
  • Mode DFTI_REAL_STORAGE can have the default value only and cannot be set by the DftiSetValue function (i.e. DFTI_REAL_STORAGE = DFTI_REAL_REAL)
  • The ILP64 version of Intel® MKL does not currently support FFTs with any one dimension larger than 2^31-1. Any 1D FFT larger than 2^31-1 or any multi-dimensional FFT with any dimension greater than 2^31-1 will return the "DFTI_1D_LENGTH_EXCEEDS_INT32" error message. Note that this does not exclude the possibility of performing multi-dimensional FFTs with more than 2^31-1 elements; as long as any one dimension length does not exceed 2^31-1
  • Some limitations exist on arrays sizes for Cluster FFT functions. See mklman.pdf for a detailed description
  • When a dynamically linked application uses Cluster FFT functionality, it is required to put the static Intel® MKL interface libraries on the link line as well. For example: -Wl,--start-group $MKL_LIB_PATH/libmkl_intel_lp64.a $MKL_LIB_PATH/libmkl_cdft_core.a -Wl,--end-group $MKL_LIB_PATH/libmkl_blacs_intelmpi20_lp64.a -L$MKL_LIB_PATH -lmkl_intel_thread -lmkl_core -liomp5 -lpthread

 


Limitations to the LAPACK functions:

  • The ILAENV function, which is called from the LAPACK routines to choose problem-dependent parameters for the local environment, cannot be replaced by a user's version
  • second() and dsecnd() functions may not provide correct answers in the case where the CPU frequency is not constant.
  • As of version 10.0 the following two issues apply when linking to the dynamic libraries:
    • A user provided XERBLA will not be invoked if LAPACK is called with illegal input parameters. The default XERBLA will be used instead.
    • A user may encounter a segment violation if they call the LP64 interface to LAPACK with illegal parameters. This is because a request may be made to allocate a negative amount of memory.

Limitations to the Vector Math Library (VML) and Vector Statistical Library (VSL) functions:

  • Usage of mkl_vml.fi may produce warning about TYPE ERROR_STRUCTURE length
  • In case user needs to build custom DLL that contains references to Intel® MKL functions, the Intel® MKL DLL Builder Tool should be used. Other DLL build techniques are not supported

 


Limitations to the ScaLAPACK functions:

  • The user can not substitute PJLAENV for their own version. This function is called by ScaLAPACK routines to choose problem-dependent parameters for the local environment.
  • There are possible problems with getting global environment variables such as MKL_BLACS_MPI by -genvlist by MPICH2. In this case, try to set all necessary environment variables by using the control panel. From the System control panel select the "Advanced" tab and click the "Environment Variables" button.

 


Limitations to the ILP64 version of Intel® MKL:

  • The ILP64 version of Intel® MKL does not contain the complete functionality of the library. For a full listing of what is in the ILP64 version refer to the user's guide in the doc directory.

 


Limitations to the Java examples:

  • The Java examples don't work if the path to the JDK contains spaces. Please use quotes to set JAVA_HOME in those cases. For example: set JAVA_HOME="C:\Program Files\Java\jdk1.6.0_06"

 

The DHPL_CALL_CBLAS option is not allowed when building the hybrid version of MP LINPACK.

We recommend that /Od be used for the 10.0 Intel® compilers when compiling test source code available with Intel® MKL. Current build scripts do not specify this option and default behavior for these compilers has changed to provide vectorization.


Limitations to dummy libraries:

  • Dummy libraries cannot be used in #pragma constructions. Dummy libraries cannot be linked by Intel compiler as a driver. Please see Chapter 3 of User's Guide for more information

All VSL functions return an error status, i.e., default VSL API is a function style now rather than a subroutine style used in earlier Intel® MKL versions. This means that Fortran users should call VSL routines as functions. For example:

errstatus = vslrnggaussian(method, stream, n, r, a, sigma)

rather than subroutines:

call vslrnggaussian(method, stream, n, r, a, sigma)

Nevertheless, Intel® MKL provides a subroutine-style interface for backward compatibility. To use subroutine-style interface, manually include mkl_vsl_subroutine.fi file instead of mkl_vsl.fi by changing the line include 'mkl_vsl.fi' mkl.fi (in the include directory) with the line include 'mkl_vsl_subroutine.fi'. VSL API changes don't affect C/C++ users.


Memory Allocation:

In order to achieve better performance, memory allocated by Intel® MKL is not released. This behavior is by design and is a one time occurrence for Intel® MKL routines that require workspace memory buffers. Even so, the user should be aware that some tools may report this as a memory leak. Should the user wish, memory can be released by the user program through use of a function (MKL_FreeBuffers()) made available in Intel® MKL or memory can be released after each call by setting the environment variable MKL_DISABLE_FAST_MM (see User's Guide in the doc directory for more details). Using one of these methods to release memory will not necessarily stop programs from reporting memory leaks, and in fact may increase the number of such reports should you make multiple calls to the library thereby requiring new allocations with each call. Memory not released by one of the methods described will be released by the system when the program ends. To avoid this restriction disable memory management as described above.


Other:

The GMP component is located in the solver library. For Intel® 64 and IA-64 platforms these components support only LP64 interface.

Using /MT when linking with multi-threaded Intel® MKL is recommended. Use of /MD with Microsoft* Visual C++* .NET 2003 may cause linking errors.

 

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