Forum poll: Intel MKL and threading

Intel MKL users,

We would like to hear from you how you are using Intel MKL with threading. Do you use the parallel or sequential MKL? How do your multithreaded applications use MKL? We would appreciate you to complete a short survey. It takes no more than 5 minutes. Your feedback will help us to make Intel MKL a better product. Thanks!

Survey link:


Troubleshooting HOWTO: Bad hardware? MPSS? Configuration?

Are you having problems with your hardware (Cannot see your Intel(R) Xeon Phi(tm) coprocessor?  Sporadic accessibility?) or with the Intel(R) Manycore Platform Software Stack (Intel(R) MPSS) running reliably?

Attached to this post are PDF "flowcharts" that explain how you can troubleshoot the problem (note:  Both Linux and Windows flowcharts are available), and shows what information you will want to collect if you need to escalate your issue to your OEM provider or Intel.

What collateral/documentation do you want to see?

Do you have questions that you are not finding the answers for in our documentation?  Need more training, source code examples, on what specifically?   Help us understand what's missing so that we can make sure we develop documentation you care about (what is important, and what is nice to have)!   Thank you

FAQS: Compilers, Libraries, Performance, Profiling and Optimization.

In the period prior to the launch of Intel® Xeon Phi™ coprocessor, Intel collected questions from developers who had been involved in pilot testing. This document contains some of the most common questions asked. Additional information and Best-Known-Methods for the Intel Xeon Phi coprocessor can be found here.

The Intel® Compiler reference guides can be found at:

Оптимизировали, оптимизировали, да не выоптимизировали!

Оптимизация? Конечно, каждый сталкивался с данной задачей при разработке своих, сколь-нибудь значительных, требующих определённых вычислений, приложений. При этом способов оптимизировать код существует огромное множество, и, как следствие, различных путей сделать это в автоматическом режиме с помощью опций компилятора. Вот здесь и возникает проблема – как выбрать то, что нужно нам и не запутаться?

Links to instruction documentation

Regarding intel MIC offload error: buffer write failed

I am trying to explore the code offloading construct .In the following program
 the offloaded region fetches the architecture of MIC card.
void main()
  FILE *fp,*fp1;
 char data[100],data1[100],final[100];
#pragma offload target(mic: 0) inout(data , fp)
	fp=popen("uname -m","r");
	fread(data, sizeof(char),100 , fp);
Here are three sample runs of this program:
  • The first run succeeds ,

Can AVX instruction be executed in parallel


Can two avx instrcutions can be executed in parallel?

For example,


            a1= _mm256_load_ps((Rin +offset)); 
            a2= _mm256_load_ps((Gin +offset));  
            a3= _mm256_load_ps((Bin +offset));

            ac0 = _mm256_mul_ps(a1, in2outAvx_11); 
            ac1 = _mm256_mul_ps(a2, in2outAvx_12);
            ac2 = _mm256_mul_ps(a3, in2outAvx_13);
            z0 = _mm256_add_ps(ac0,ac1);
            z1 = _mm256_add_ps(z0, ac2);

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.

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