1HPL_dlange(3)                HPL Library Functions               HPL_dlange(3)
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NAME

6       HPL_dlange - Compute ||A||.
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SYNOPSIS

9       #include "hpl.h"
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11       double  HPL_dlange(  const  HPL_T_NORM  NORM, const int M, const int N,
12       const double * A, const int LDA );
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DESCRIPTION

15       HPL_dlange returns  the value of the one norm,  or the  infinity  norm,
16       or the element of largest absolute value of a matrix A:
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18          max(abs(A(i,j))) when NORM = HPL_NORM_A,
19          norm1(A),        when NORM = HPL_NORM_1,
20          normI(A),        when NORM = HPL_NORM_I,
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22       where  norm1  denotes the one norm of a matrix (maximum column sum) and
23       normI denotes  the infinity norm of a matrix (maximum row  sum).   Note
24       that max(abs(A(i,j))) is not a matrix norm.
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ARGUMENTS

27       NORM    (local input)           const HPL_T_NORM
28               On  entry,   NORM  specifies  the  value to be returned by this
29               function as described above.
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31       M       (local input)           const int
32               On entry,  M  specifies  the number  of rows of the  matrix  A.
33               M must be at least zero.
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35       N       (local input)           const int
36               On  entry,   N specifies the number of columns of the matrix A.
37               N must be at least zero.
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39       A       (local input)           const double *
40               On entry,  A  points to an  array of dimension   (LDA,N),  that
41               contains the matrix A.
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43       LDA     (local input)           const int
44               On  entry,  LDA specifies the leading dimension of the array A.
45               LDA must be at least max(1,M).
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EXAMPLE

48       #include "hpl.h"
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50       int main(int argc, char *argv[])
51       {
52          double a[2*2];
53          a[0] = 1.0; a[1] = 3.0; a[2] = 2.0; a[3] = 4.0;
54          norm = HPL_dlange( HPL_NORM_I, 2, 2, a, 2 );
55          printf("norm=%f\n", norm);
56          exit(0); return(0);
57       }
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SEE ALSO

60       HPL_dlaprnt (3), HPL_fprintf (3).
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64HPL 2.2                        February 24, 2016                 HPL_dlange(3)
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