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dtrtri.f(3) LAPACK dtrtri.f(3)

NAME

dtrtri.f

SYNOPSIS

Functions/Subroutines


subroutine dtrtri (UPLO, DIAG, N, A, LDA, INFO)
DTRTRI

Function/Subroutine Documentation

subroutine dtrtri (character UPLO, character DIAG, integer N, double precision, dimension( lda, * ) A, integer LDA, integer INFO)

DTRTRI

Purpose:


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

Parameters:

UPLO


UPLO is CHARACTER*1
= 'U': A is upper triangular;
= 'L': A is lower triangular.

DIAG


DIAG is CHARACTER*1
= 'N': A is non-unit triangular;
= 'U': A is unit triangular.

N


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

A


A is DOUBLE PRECISION 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


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

INFO


INFO is 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.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 111 of file dtrtri.f.

Author

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Tue Nov 14 2017 Version 3.8.0