Segmentation fault on declaring variable while using mkl for matrix vector multiplication

[prakrati]

Hello ,
I am trying to use mkl library to do matrix vector multiplication .When I am declaring a variable char t3 ,its giving segmentation fault
and when I am commenting it ,its running fine.Please help me debug this problem
I have bolded the line and wrote a comment on it to identify it.

The error that I am getting is as follows:Output :

./matrixVectorMultMKL2.o 10 10 1
Intializing.. size = 10
Performing multiplication 100 times..
Segmentation fault

Please help!!!





#include

#include
#include "mkl_cblas.h"
#include "mkl.h"
#include

#include
void DisplayVector(double *vector, int size)
{
int i;
for (i=0 ; i printf("%lf ",vector);
}
printf("\\n");
}

static inline unsigned long long getticks() {
unsigned int _hi,_lo;
__asm__ __volatile__("rdtsc":"=a"(_lo),"=d"(_hi));
return ((unsigned long long)_hi << 32) | _lo;
}

double getTimeInSeconds(long long ticks) {

// first calculate processor speed
long long t1,t2,processorSpeed;
double timeInSeconds;
t1 = getticks();

sleep(1);
t2 = getticks();
processorSpeed = t2 - t1;
// now calculate time
timeInSeconds = ((double) ticks) / ((double) processorSpeed);

//timeInSeconds = ((double) ticks) / CLOCKS_PER_SEC ;
return timeInSeconds;
}

int main(int argc,char *argv[])
{
int i, size = atoi(argv[1]);
//int i;
//int size = 3;
long long t1,t2;
double *matrix = (double *) mkl_malloc (size * size * sizeof(double),16);
double *vector = (double *) mkl_malloc (size * sizeof(double),16);
double *resultVector = (double *) mkl_malloc (size * sizeof(double),16);

char t3; //Segmentation fault is coming due to this line

printf("Intializing.. size = %d\\n",size);
for (i=0; i<(size*size); i++) {
//matrix = i+1;
matrix = 1;
}
for (i=0;i //vector = i+1;
vector = 1;
resultVector = 0;
}

/*
void cblas_dgemv(const CBLAS_ORDER order,
const CBLAS_TRANSPOSE TransA, const MKL_INT M, const MKL_INT N,
const double alpha, const double *A, const MKL_INT lda,
const double *X, const MKL_INT incX, const double beta,
double *Y, const MKL_INT incY);

typedef enum {CblasRowMajor=101, CblasColMajor=102} CBLAS_ORDER;
typedef enum {CblasNoTrans=111, CblasTrans=112, CblasConjTrans=113} CBLAS_TRANSPOSE; */

mkl_set_num_threads ( 8 );
printf("Performing multiplication 100 times..\\n");

t1 = getticks();
//printf("t1 = %Ld\\n",t1);
for (i=0;i<100;i++) {
cblas_dgemv(CblasRowMajor, CblasNoTrans, size, size,1,matrix,size,vector,1,0,resultVector,1);
}
t2 = getticks();

//printf("Clock ticks required : %Ld\\n",t2 - t1);

//t = getTimeInSeconds(t2 - t1);

printf("Time for multiplication : %lf\\n",(getTimeInSeconds(t2 - t1)) / 100.0);

//printf("Result vector : ");
//DisplayVector(resultVector,size);

return 0;
}

[mecej4]

Which OS, C compiler, what version of MKL, and what were the compiler options used?

With Intel C 11.1.073 (IA32 or intel64) on SuSE Linux 11.3, the program, copied exactly from your post, can be compiled and run with no error messages when compiled with "icc -mkl -O ".

[Gennady_F_Intel]

Yes, more details will help to reproduce the problem.

I used to try with the latest Intel compiler v12 bundled ( aka Composer XE 2011). no problems..

--Gennady

[prakrati]

I am compiling it with GCC .The version of gcc and mkl is as follows:
GCC version used : gcc (GCC) 3.4.6 20060404 (Red Hat 3.4.6-8)

MKL version used : /app/intel/mkl/10.2.5.035

gcc matrixVectorMultMKL3.c -Wall -L $(MKLPATH) -I $(MKLINCLUDE) -lmkl_intel_ilp64 -lmkl_intel_thread -lmkl_core -liomp5 -lpthread -lm -o matrixVectorMultMKL3.o

When I compiled using your command ,it ran successfully so I am just confused why its not running with the previous command

Thanks and Regards
Prakrati

[Gennady_F_Intel]

That's very strange. Please try to remove all mkl routines calling. Will then be the same result?

[mecej4]

If you want to use ILP64 libraries, you probably have to tell GCC through suitable options that the default integer should be 64 bits.