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HPL_dlange(3)                HPL Library Functions               HPL_dlange(3)

NAME
       HPL_dlange - Compute ||A||.

SYNOPSIS
       #include "hpl.h"

       double HPL_dlange( const HPL_T_NORM NORM, const int M, const int N,
       const double * A, const int LDA );

DESCRIPTION
       HPL_dlange returns  the value of the one norm,  or the infinity norm,
       or the element of largest absolute value of a matrix A:

          max(abs(A(i,j))) when NORM = HPL_NORM_A,
          norm1(A),        when NORM = HPL_NORM_1,
          normI(A),        when NORM = HPL_NORM_I,

       where norm1 denotes the one norm of a matrix (maximum column sum) and
       normI denotes  the infinity norm of a matrix (maximum row sum).  Note
       that max(abs(A(i,j))) is not a matrix norm.

ARGUMENTS
       NORM    (local input)           const HPL_T_NORM
               On entry,  NORM  specifies  the  value to be returned by this
               function as described above.

       M       (local input)           const int
               On entry,  M  specifies  the number  of rows of the matrix A.
               M must be at least zero.

       N       (local input)           const int
               On entry,  N specifies the number of columns of the matrix A.
               N must be at least zero.

       A       (local input)           const double *
               On entry,  A  points to an  array of dimension  (LDA,N), that
               contains the matrix A.

       LDA     (local input)           const int
               On entry, LDA specifies the leading dimension of the array A.
               LDA must be at least max(1,M).

EXAMPLE
       #include "hpl.h"

       int main(int argc, char *argv[])
       {
          double a[2*2];
          a[0] = 1.0; a[1] = 3.0; a[2] = 2.0; a[3] = 4.0;
          norm = HPL_dlange( HPL_NORM_I, 2, 2, a, 2 );
          printf("norm=%f\n", norm);
          exit(0); return(0);
       }

SEE ALSO
       HPL_dlaprnt (3), HPL_fprintf (3).

HPL 2.1                        October 26, 2012                  HPL_dlange(3)