
STRSV(l) BLAS routine STRSV(l)
NAME
STRSV  solve one of the systems of equations A*x = b, or A'*x = b,
SYNOPSIS
SUBROUTINE STRSV ( UPLO, TRANS, DIAG, N, A, LDA, X, INCX )
INTEGER INCX, LDA, N
CHARACTER*1 DIAG, TRANS, UPLO
REAL A( LDA, * ), X( * )
PURPOSE
STRSV solves one of the systems of equations
where b and x are n element vectors and A is an n by n unit, or nonunit, upper or lower
triangular matrix.
No test for singularity or nearsingularity is included in this routine. Such tests must
be performed before calling this routine.
PARAMETERS
UPLO  CHARACTER*1.
On entry, UPLO specifies whether the matrix is an upper or lower triangular matrix
as follows:
UPLO = 'U' or 'u' A is an upper triangular matrix.
UPLO = 'L' or 'l' A is a lower triangular matrix.
Unchanged on exit.
TRANS  CHARACTER*1.
On entry, TRANS specifies the equations to be solved as follows:
TRANS = 'N' or 'n' A*x = b.
TRANS = 'T' or 't' A'*x = b.
TRANS = 'C' or 'c' A'*x = b.
Unchanged on exit.
DIAG  CHARACTER*1.
On entry, DIAG specifies whether or not A is unit triangular as follows:
DIAG = 'U' or 'u' A is assumed to be unit triangular.
DIAG = 'N' or 'n' A is not assumed to be unit triangular.
Unchanged on exit.
N  INTEGER.
On entry, N specifies the order of the matrix A. N must be at least zero.
Unchanged on exit.
A  REAL array of DIMENSION ( LDA, n ).
Before entry with UPLO = 'U' or 'u', the leading n by n upper triangular part of
the array A must contain the upper triangular matrix and the strictly lower trian
gular part of A is not referenced. Before entry with UPLO = 'L' or 'l', the lead
ing n by n lower triangular part of the array A must contain the lower triangular
matrix and the strictly upper triangular part of A is not referenced. Note that
when DIAG = 'U' or 'u', the diagonal elements of A are not referenced either, but
are assumed to be unity. Unchanged on exit.
LDA  INTEGER.
On entry, LDA specifies the first dimension of A as declared in the calling (sub)
program. LDA must be at least max( 1, n ). Unchanged on exit.
X  REAL array of dimension at least
( 1 + ( n  1 )*abs( INCX ) ). Before entry, the incremented array X must contain
the n element righthand side vector b. On exit, X is overwritten with the solution
vector x.
INCX  INTEGER.
On entry, INCX specifies the increment for the elements of X. INCX must not be
zero. Unchanged on exit.
Level 2 Blas routine.
 Written on 22October1986. Jack Dongarra, Argonne National Lab. Jeremy Du
Croz, Nag Central Office. Sven Hammarling, Nag Central Office. Richard Hanson,
Sandia National Labs.
BLAS routine 16 October 1992 STRSV(l) 
