LAPACK  3.4.2
LAPACK: Linear Algebra PACKage
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dtrti2.f File Reference

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Functions/Subroutines

subroutine dtrti2 (UPLO, DIAG, N, A, LDA, INFO)
 DTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).

Function/Subroutine Documentation

subroutine dtrti2 ( character  UPLO,
character  DIAG,
integer  N,
double precision, dimension( lda, * )  A,
integer  LDA,
integer  INFO 
)

DTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).

Download DTRTI2 + dependencies [TGZ] [ZIP] [TXT]
Purpose:
 DTRTI2 computes the inverse of a real upper or lower triangular
 matrix.

 This is the Level 2 BLAS version of the algorithm.
Parameters:
[in]UPLO
          UPLO is CHARACTER*1
          Specifies whether the matrix A is upper or lower triangular.
          = 'U':  Upper triangular
          = 'L':  Lower triangular
[in]DIAG
          DIAG is CHARACTER*1
          Specifies whether or not the matrix A is unit triangular.
          = 'N':  Non-unit triangular
          = 'U':  Unit triangular
[in]N
          N is INTEGER
          The order of the matrix A.  N >= 0.
[in,out]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.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,N).
[out]INFO
          INFO is INTEGER
          = 0: successful exit
          < 0: if INFO = -k, the k-th argument had an illegal value
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
September 2012

Definition at line 111 of file dtrti2.f.

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