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.TH HPL_dlange 3 "September 10, 2008" "HPL 2.0" "HPL Library Functions"
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.SH NAME
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HPL_dlange \- Compute ||A||.
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.SH SYNOPSIS
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\fB\&#include "hpl.h"\fR
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\fB\&double\fR
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\fB\&HPL_dlange(\fR
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\fB\&const HPL_T_NORM\fR
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\fI\&NORM\fR,
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\fB\&const int\fR
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\fI\&M\fR,
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\fB\&const int\fR
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\fI\&N\fR,
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\fB\&const double *\fR
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\fI\&A\fR,
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\fB\&const int\fR
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\fI\&LDA\fR
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\fB\&);\fR
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.SH DESCRIPTION
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\fB\&HPL_dlange\fR
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returns  the value of the one norm,  or the infinity norm,
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or the element of largest absolute value of a matrix A:
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   max(abs(A(i,j))) when NORM = HPL_NORM_A,
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   norm1(A),        when NORM = HPL_NORM_1,
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   normI(A),        when NORM = HPL_NORM_I,
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where norm1 denotes the one norm of a matrix (maximum column sum) and
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normI denotes  the infinity norm of a matrix (maximum row sum).  Note
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that max(abs(A(i,j))) is not a matrix norm.
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.SH ARGUMENTS
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.TP 8
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NORM    (local input)           const HPL_T_NORM
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On entry,  NORM  specifies  the  value to be returned by this
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function as described above.
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.TP 8
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M       (local input)           const int
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On entry,  M  specifies  the number  of rows of the matrix A.
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M must be at least zero.
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.TP 8
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N       (local input)           const int
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On entry,  N specifies the number of columns of the matrix A.
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N must be at least zero.
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.TP 8
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A       (local input)           const double *
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On entry,  A  points to an  array of dimension  (LDA,N), that
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contains the matrix A.
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.TP 8
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LDA     (local input)           const int
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On entry, LDA specifies the leading dimension of the array A.
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LDA must be at least max(1,M).
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.SH EXAMPLE
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\fI\&#include "hpl.h"\fR
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int main(int argc, char *argv[])
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.br
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{
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.br
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   double a[2*2];
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.br
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   a[0] = 1.0; a[1] = 3.0; a[2] = 2.0; a[3] = 4.0;
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.br
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   norm = HPL_dlange( HPL_NORM_I, 2, 2, a, 2 );
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.br
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   printf("norm=%f\en", norm);
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.br
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   exit(0); return(0);
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.br
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}
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.SH SEE ALSO
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.BR HPL_dlaprnt \ (3),
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.BR HPL_fprintf \ (3).