Flashnux

GNU/Linux man pages

• CentOS
• Debian
• Red Hat
• Ubuntu
• Unix

Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

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

GNU/Linux	CentOS 4.8	i386
	strtri(l)

---

STRTRI

NAME
SYNOPSIS
PURPOSE
ARGUMENTS

---

NAME

STRTRI - compute the inverse of a real upper or lower triangular matrix A

SYNOPSIS

	SUBROUTINE STRTRI(		UPLO, DIAG, N, A, LDA, INFO )
	CHARACTER		DIAG, UPLO
	INTEGER		INFO, LDA, N
	REAL		A( LDA, * )

PURPOSE

STRTRI computes the inverse of a real upper or lower triangular matrix A. This is the Level 3 BLAS version of the algorithm.

ARGUMENTS

UPLO (input) CHARACTER*1

= ’U’: A is upper triangular;
= ’L’: A is lower triangular.

DIAG (input) CHARACTER*1

= ’N’: A is non-unit triangular;
= ’U’: A is unit triangular.

N (input) INTEGER

The order of the matrix A. N >= 0.

A (input/output) REAL array, dimension (LDA,N)

On entry, the triangular matrix A. If UPLO = ’U’, the leading N-by-N upper triangular part of the array A contains the upper triangular matrix, and the strictly lower triangular part of A is not referenced. If UPLO = ’L’, the leading N-by-N lower triangular part of the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced. If DIAG = ’U’, the diagonal elements of A are also not referenced and are assumed to be 1. On exit, the (triangular) inverse of the original matrix, in the same storage format.

LDA (input) INTEGER

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

INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, A(i,i) is exactly zero. The triangular matrix is singular and its inverse can not be computed.

---

---

strtri(l)