dtrtrs (3)  Linux Manuals
NAME
dtrtrs.f 
SYNOPSIS
Functions/Subroutines
subroutine dtrtrs (UPLO, TRANS, DIAG, N, NRHS, A, LDA, B, LDB, INFO)
DTRTRS
Function/Subroutine Documentation
subroutine dtrtrs (characterUPLO, characterTRANS, characterDIAG, integerN, integerNRHS, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( ldb, * )B, integerLDB, integerINFO)
DTRTRS
Purpose:

DTRTRS solves a triangular system of the form A * X = B or A**T * X = B, where A is a triangular matrix of order N, and B is an NbyNRHS matrix. A check is made to verify that A is nonsingular.
Parameters:

UPLO
UPLO is CHARACTER*1 = 'U': A is upper triangular; = 'L': A is lower triangular.
TRANSTRANS is CHARACTER*1 Specifies the form of the system of equations: = 'N': A * X = B (No transpose) = 'T': A**T * X = B (Transpose) = 'C': A**H * X = B (Conjugate transpose = Transpose)
DIAGDIAG is CHARACTER*1 = 'N': A is nonunit triangular; = 'U': A is unit triangular.
NN is INTEGER The order of the matrix A. N >= 0.
NRHSNRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
AA is DOUBLE PRECISION array, dimension (LDA,N) The triangular matrix A. If UPLO = 'U', the leading NbyN 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 NbyN 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.
LDALDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).
BB is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, the right hand side matrix B. On exit, if INFO = 0, the solution matrix X.
LDBLDB is INTEGER The leading dimension of the array B. LDB >= max(1,N).
INFOINFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value > 0: if INFO = i, the ith diagonal element of A is zero, indicating that the matrix is singular and the solutions X have not been computed.
Author:

Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
 November 2011
Definition at line 140 of file dtrtrs.f.
Author
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