table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlantr.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlantr.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlantr.f
SYNOPSIS¶
Functions/Subroutines¶
double precision function DLANTR (norm, uplo, diag, m, n,
a, lda, work)
DLANTR returns the value of the 1-norm, or the Frobenius norm, or the
infinity norm, or the element of largest absolute value of a trapezoidal or
triangular matrix.
Function/Subroutine Documentation¶
double precision function DLANTR (character norm, character uplo, character diag, integer m, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) work)¶
DLANTR returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a trapezoidal or triangular matrix.
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. !>
Returns
DLANTR
!> !> 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 consistent matrix norm. !>
Parameters
NORM
!> NORM is CHARACTER*1 !> Specifies the value to be returned in DLANTR as described !> above. !>
UPLO
!> UPLO is 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
!> DIAG is CHARACTER*1 !> Specifies whether or not the matrix A has unit diagonal. !> = 'N': Non-unit diagonal !> = 'U': Unit diagonal !>
M
!> M is 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
!> N is 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
!> A is 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 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
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(M,1). !>
WORK
!> WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)), !> where LWORK >= M when NORM = 'I'; otherwise, WORK is not !> referenced. !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 139 of file dlantr.f.
Author¶
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Version 3.12.0 | LAPACK |