topic Solving a system of equation in Intel® oneAPI Math Kernel Library

Solving a system of equation

majides — Sun, 23 Jan 2011 00:04:42 GMT

I'm a beginner in using MKL library , Actually I want to solve a system of equation by calling dgetf and dgetrs function , but the segmentation fault error always appear when I run my program. The equation is Ax=B, which A is a dim*dim array and B is a dim array. Here is the part of my program which solves the system of equation

void Solve(int dim, double* A, double* B)

{

int* piv = new int [dim];

int info = 0;

int nhrs = 1;

char p = 'T';

dgetrf(&dim, &dim, A, &dim, piv, &info);

if(info)

{

printf("Fact failed -- %d\\n", info);

for(int i = 0; i < dim; i ++)

{

for(int j = 0; j < dim; j ++)

printf("%e\\t", A[i*dim+j]);

printf("\\n");

}

exit(0);

}

cout<<"\\n","\\n";

dgetrs(&p, &dim, &nhrs, A,&dim, piv, B, &dim, &info);

if(info)

{

printf("Solve failed -- %d\\n", info);

exit(0);

}

free(piv);

}

It would be highly appreciated if you can hel me .

Solving a system of equation

mecej4 — Sun, 23 Jan 2011 05:15:51 GMT

You have posted a fragment of a program. There is no point in listing all the possible ways in which that fragment could be expanded into a runnable program that causes a runtime error. Nor is there much to gain from posting one example of code that runs correctly, even though this is quite a bit easier to do.

Present a complete example and you will improve the chances that someone will tell you what the mistakes are.

Solving a system of equation

majides — Sun, 23 Jan 2011 19:36:55 GMT

Thanksfor your comment , I didn't get your meaning , here is the function which should solve my system of equation Ax=B, where A is the Matrix ofcoefficient, and in a n*n array , and b is the right side of my equation which is a n array . This is a complete example forexampleif youputA={1,2,1,2,1,1,1,1,0} and B={230} and send it ti the Sole the error segmentation fault appears.

Solving a system of equation

Gennady_F_Intel — Sun, 23 Jan 2011 20:13:58 GMT

I checked the problem with the version 10.2 Update7. win7. 32bit. No exceptions were found with the inputs you pointed.

for example - see the results after dgetrf

dgetrf passed -- 0

2.000000e+000 5.000000e-001 5.000000e-001

1.000000e+000 1.500000e+000 3.333333e-001

1.000000e+000 5.000000e-001 -6.666667e-001

--Gennady

Solving a system of equation

majides — Mon, 24 Jan 2011 02:00:43 GMT

Thanks for your reply , can you please say me the libraries you have linked ?

Solving a system of equation

mecej4 — Mon, 24 Jan 2011 02:26:22 GMT

B={230} and send it ti the Sole the error segmentation fault appears

B={230} initializes only B[0], leaving B[1] and B[2] unset.

send it ti the Sole

????

Solving a system of equation

majides — Mon, 24 Jan 2011 02:33:25 GMT

sorry I mean B={2,3,0} not {230}.

Solving a system of equation

Gennady_F_Intel — Mon, 24 Jan 2011 06:10:05 GMT

"mkl_intel_c.lib mkl_intel_thread.lib mkl_core.lib libiomp5md.lib"

if you need I can send the VS2008 project with yourexample.

Solving a system of equation

majides — Tue, 25 Jan 2011 22:28:36 GMT

Thank you so much, my question is that do you know which libraries are equal to this library in linux version , I'm using a linux version of mkl library so I don't know which library I should link for this new version because the guide library for last version is omitted in this version .

Solving a system of equation

TimP — Tue, 25 Jan 2011 23:47:04 GMT

Enough has changed since the MKL which had libguide, and enough depends on input from you, that the link advisor at the top of this forum would be better than taking a guess, although basically there's a direct correspondence between libraries needed for Windows and those for linux.

Solving a system of equation

Gennady_F_Intel — Wed, 26 Jan 2011 08:58:47 GMT

See here the direct link to the adviser