Scientific Operations

HPL_idamax HPL 2.2 Library Functions February 24, 2016


HPL_idamax 1st k s.t. |x_k| = max_i(|x_i|).


#include "hpl.h"

int HPL_idamax( const int N, const double * X, const int INCX );


HPL_idamax returns the index in an n-vector x of the first element having maximum absolute value.


N       (local input)                 const int
        On entry, N specifies the length of the vector x. N  must  be
        at least zero.
X       (local input)                 const double *
        On entry,  X  is an incremented array of dimension  at  least
        ( 1 + ( n - 1 ) * abs( INCX ) )  that  contains the vector x.
INCX    (local input)                 const int
        On entry, INCX specifies the increment for the elements of X.
        INCX must not be zero.


#include "hpl.h"

int main(int argc, char *argv[])
   double x[3];
   int    imax;
   x[0] = 1.0; x[1] = 3.0; x[2] = 2.0;
   imax = HPL_idamax( 3, x, 1 );
   printf("imax=%d\n", imax);

See Also

HPL_daxpy, HPL_dcopy, HPL_dscal, HPL_dswap.