# FreeBSD Manual Pages

```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 = 1.0; a = 3.0; a = 2.0; a = 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 2.3			       December	2, 2018			 HPL_dlange(3)
```

NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | EXAMPLE | SEE ALSO

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