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Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

ISBN : 978-2-7460-9712-4
EAN : 9782746097124
(Editions ENI)

GNU/Linux	CentOS 4.8	i386
	slantr(l)

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SLANTR

NAME
SYNOPSIS
PURPOSE
DESCRIPTION
ARGUMENTS

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NAME

SLANTR - return 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

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 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, 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.

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slantr(l)