Intel® Math Kernel Library

ZGETRS memory corruption(?) with denormal numbers

We recently encountered a rather strange issue when passing denormal numbers in the right-hand-side matrix to ZGETRS. Attached is a small C++ file that reproduces this error.

In this file, we set up a left- and right-hand-side matrix, factorize the lhs with ZGETRF and then call ZGETRS. Before and after the call to ZGETRS, we call the standard math fmod function with some arbitrary numbers. The call to fmod that happens before the ZGETRS call works as expected. The call afterwards however returns nan, regardless of what numbers are passed.

Does Intel MKL Pardiso come with selected Matrix Inversion

Hi, I am trying to compute the inverse of a sparse matrix. I saw in the pardiso website that manipulating certain parameters may result in computing the inverse of selected rows and columns of the matrix. 

Does anyone know if intel MKL pardiso has this functionality and if so any sample code for the same ? 

dggev deterministic behaviour

Hello, 

I am using dggev (mkl versions 11.2.1 & 11.2.2) and i notice some non deterministic behaviour concerning eigenvalues near zero and infinite eigenvalues and eigenvectors. I use the parallel mkl version with gomp (not intel omp). I compile my code using gcc 4.4.7. It seems that there are (at least) 2 sets of output that differ in the regions mentioned. I also use mkl allocators to ensure my memory is aligned. It is a rare phainomenon, but still, could you have a look? 

Thanks! 

Inplace permutation

Hello,

I need to permute a vector according to an index array jpvt returned by ?geqp3.  In the example lapack/source/dgeqpfx.f it is done using an auxiliary array. I would like to do the transformation inplace (or at least with O(1) extra memory), but as you can see from the attached source code, I don’t seem to be able to use ?laswp correctly. Can this be used for this kind of transformation ? If yes, how ? If no, is there another way to do this ?

Thank you in advance.

 

Do I need Pardiso_64? iparm(18) reports negative value

I am attempting to solve a large complex, symmetric matrix using PARDISO.  The matrix has approximately 1,000,000 equations, and 91,000,000 non-zeros.  I suspect that during Pardiso's factorization stage, the number of non-zeroes in the factors exceed the 32-bit integer size limit (i.e. 2^31).  I suspect this because pardiso returns a very large negative number for iparm(18), after the factorization stage.

So ... here's the questions.

Application Shutdown on call to DftiCreateDescriptor for Intel MKL c++

Hello all, 

I have built a C++plugin to that employs MKL's fft libraries for filtering purposes. This plugin is used by a C++ compute system that generates data on demand by any other application. This compute system is used by a C# application. When I request data of my plugin, I can debug up to my DftiCreateDescriptor call only for my application to shut down on execution of said call.

The following is the output generated:

A bug in zgelsd in MKL 15.0

Hi there, 

Thank you for reading this post. 

I got these error messages when calling zgelsd  in MKL 15.0 to solve  a fairly large matrix,

Intel MKL INTERNAL ERROR: Condition 1 detected in function DLASD4.

Intel MKL INTERNAL ERROR: Condition 1 detected in function DLASD8.

I googled online and found the exact issue here https://software.intel.com/en-us/forums/topic/373673, where it said the bug had been fixed in MKL 11 update 5.

Iscriversi a Intel® Math Kernel Library