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NAME
     dlantr - return the value of the one norm, or the  Frobenius
     norm,  or the infinity norm, or the element of largest abso-
     lute value of a trapezoidal or triangular matrix A

SYNOPSIS
     DOUBLE PRECISION FUNCTION DLANTR( NORM, UPLO, DIAG, M, N, A,
               LDA, WORK )

     CHARACTER DIAG, NORM, UPLO

     INTEGER LDA, M, N

     DOUBLE PRECISION A( LDA, * ), WORK( * )



     #include <sunperf.h>

     double dlantr(char norm, char uplo, char diag, int m, int n,
               double *da, int lda) ;

PURPOSE
     DLANTR  returns the value of the one norm,  or the Frobenius
     norm,  or  the   infinity norm,  or the  element of  largest
     absolute value  of a trapezoidal or triangular matrix A.


DESCRIPTION
     DLANTR returns the value

        DLANTR = ( max(abs(A(i,j))), NORM = 'M' or 'm'
                 (
                 ( norm1(A),         NORM = '1', 'O' or 'o'
                 (
                 ( normI(A),         NORM = 'I' or 'i'
                 (
                 ( normF(A),         NORM = 'F', 'f', 'E' or 'e'

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


ARGUMENTS
     NORM      (input) CHARACTER*1
               Specifies the value to be returned  in  DLANTR  as
               described above.

     UPLO      (input) CHARACTER*1
               Specifies whether the matrix A is upper  or  lower
               trapezoidal.  = 'U':  Upper trapezoidal
               = 'L':  Lower trapezoidal Note that A is  triangu-
               lar instead of trapezoidal if M = N.

     DIAG      (input) CHARACTER*1
               Specifies whether or not the  matrix  A  has  unit
               diagonal.  = 'N':  Non-unit diagonal
               = 'U':  Unit diagonal

     M         (input) INTEGER
               The number of rows of the matrix A.  M >=  0,  and
               if  UPLO = 'U', M <= N.  When M = 0, DLANTR is set
               to zero.

     N         (input) INTEGER
               The number of columns of the matrix A.   N  >=  0,
               and  if UPLO = 'L', N <= M.  When N = 0, DLANTR is
               set to zero.

     A         (input) DOUBLE PRECISION array, dimension (LDA,N)
               The trapezoidal matrix A (A is triangular if  M  =
               N).   If UPLO = 'U', the leading m by n upper tra-
               pezoidal part of the array A  contains  the  upper
               trapezoidal  matrix,  and  the strictly lower tri-
               angular part of A is not referenced.   If  UPLO  =
               'L',  the leading m by n lower trapezoidal part of
               the array A contains the lower trapezoidal matrix,
               and the strictly upper triangular part of A is not
               referenced.  Note that when DIAG = 'U', the diago-
               nal  elements  of  A  are  not  referenced and are
               assumed to be one.

     LDA       (input) INTEGER
               The leading dimension of  the  array  A.   LDA  >=
               max(M,1).

     WORK      (workspace)  DOUBLE  PRECISION  array,   dimension
               (LWORK),
               where LWORK >= M when NORM = 'I'; otherwise,  WORK
               is not referenced.

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