dtrtri (l) - Linux Manuals
dtrtri: computes the inverse of a real upper or lower triangular matrix A
Command to display dtrtri
manual in Linux: $ man l dtrtri
NAME
DTRTRI - computes the inverse of a real upper or lower triangular matrix A
SYNOPSIS
- SUBROUTINE DTRTRI(
-
UPLO, DIAG, N, A, LDA, INFO )
-
CHARACTER
DIAG, UPLO
-
INTEGER
INFO, LDA, N
-
DOUBLE
PRECISION A( LDA, * )
PURPOSE
DTRTRI 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
-
= aqUaq: A is upper triangular;
= aqLaq: A is lower triangular.
- DIAG (input) CHARACTER*1
-
= aqNaq: A is non-unit triangular;
= aqUaq: A is unit triangular.
- N (input) INTEGER
-
The order of the matrix A. N >= 0.
- A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
-
On entry, the triangular matrix A. If UPLO = aqUaq, 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 = aqLaq, 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 = aqUaq, 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.
Pages related to dtrtri
- dtrtri (3)
- dtrtrs (l) - solves a triangular system of the form A * X = B or A**T * X = B,
- dtrti2 (l) - computes the inverse of a real upper or lower triangular matrix
- dtrttf (l) - copies a triangular matrix A from standard full format (TR) to rectangular full packed format (TF)
- dtrttp (l) - copies a triangular matrix A from full format (TR) to standard packed format (TP)
- dtrcon (l) - estimates the reciprocal of the condition number of a triangular matrix A, in either the 1-norm or the infinity-norm
- dtrevc (l) - computes some or all of the right and/or left eigenvectors of a real upper quasi-triangular matrix T
- dtrexc (l) - reorders the real Schur factorization of a real matrix A = Q*T*Q**T, so that the diagonal block of T with row index IFST is moved to row ILST