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slantr

 NAME
      SLANTR - 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
      REAL FUNCTION SLANTR( NORM, UPLO, DIAG, M, N, A, LDA, WORK )

          CHARACTER DIAG, NORM, UPLO

          INTEGER   LDA, M, N

          REAL      A( LDA, * ), WORK( * )

 PURPOSE
      SLANTR  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
      SLANTR returns the value

         SLANTR = ( 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 SLANTR 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 triangular
              instead of trapezoidal if M = N.

      DIAG    (input) CHARACTER*1
              Specifies whether or not the matrix A has unit diag-
              onal.  = '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, SLANTR 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, SLANTR is set to
              zero.

      A       (input) REAL array, dimension (LDA,N)
              The trapezoidal matrix A (A is triangular if M = N).
              If UPLO = 'U', the leading m by n upper trapezoidal
              part of the array A contains the upper trapezoidal
              matrix, and the strictly lower triangular 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 diagonal 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) REAL array, dimension (LWORK),
              where LWORK >= M when NORM = 'I'; otherwise, WORK is
              not referenced.