LAPACK 3.3.1 with LAPACKE: dlamch missing?

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LAPACK 3.3.1 with LAPACKE: dlamch missing?

Postby error5772 » Fri Sep 02, 2011 10:55 am

Dear people!

I searched the posts, but could not find any solution:

My LAPACK 3.3.1 on ATLAS (threaded F77-Interface) using Intel's LAPACKE-Interface
works fine, but I found no LAPACKE_dlamch()-, LAPACK_dlamch()- or dlamch_()-function
defined in the header (even not in the LAPACKE-sorce-code)! I solved the problem by
setting my own thresholds, but older results with dlamch seem to be mor accurate.

Does anyone know what to do?

Thanks

Michael
error5772
 
Posts: 19
Joined: Thu Sep 01, 2011 5:02 am

Re: LAPACK 3.3.1 with LAPACKE: dlamch missing?

Postby admin » Tue Sep 20, 2011 4:49 pm

Dear Michael,
yes indeed dlamch has not been shipped with the first release of LAPACKE.
The next LAPACKE release will include it.
You can still call directly the dlamch Fortran routine.
Something like this should work
Code: Select all
#include <stdio.h>
#include <stdlib.h>

double dlamch_( char* cmach );

int main(void)
{
  printf("============= DLAMCH =============\n");
  char cmach='S';
  double eps;
  eps = (double) dlamch_( &cmach );
  printf("LAPACK EPS = %e\n",eps);
 
  }


Julie
admin
Site Admin
 
Posts: 490
Joined: Wed Dec 08, 2004 7:07 pm

Re: LAPACK 3.3.1 with LAPACKE: dlamch missing?

Postby error5772 » Tue Oct 11, 2011 12:30 pm

Hey thanks!

This was 10-times more than I expected! The code works after
including my "lapacke.h(pp)" and changing to (C++):

extern "C" {double dlamch_( char* cmach );}

und linking with my FORTRAN -llapack! That was an
interlanguage call to Fortran or not? I thought that this is much
more complex - even for double ;-)

Thank you very much!!!

Michael
error5772
 
Posts: 19
Joined: Thu Sep 01, 2011 5:02 am


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