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Technical Reference: Base Operating System and Extensions , Volume 2
Solves systems of
equations.
BLAS Library
(libblas.a)
SUBROUTINE STPSV(UPLO, TRANS, DIAG,
N, AP, X, INCX)
INTEGER INCX, N
CHARACTER*1 DIAG, TRANS, UPLO
REAL AP(*), X(*)
SUBROUTINE DTPSV(UPLO, TRANS, DIAG,
N, AP, X, INCX)
INTEGER INCX,N
CHARACTER*1 DIAG,TRANS,UPLO
DOUBLE PRECISION AP(*), X(*)
SUBROUTINE CTPSV(UPLO, TRANS, DIAG,
N, AP, X, INCX)
INTEGER INCX,N
CHARACTER*1 DIAG,TRANS,UPLO
COMPLEX AP(*), X(*)
SUBROUTINE ZTPSV(UPLO, TRANS, DIAG,
N, AP, X, INCX)
INTEGER INCX,N
CHARACTER*1 DIAG,TRANS,UPLO
COMPLEX*16 AP(*), X(*)
The STPSV,
DTPSV, DTPSV, or ZTPSV subroutine solves one
of the systems of equations:
A * x = b
OR
A' * x =
b
where b and x are N
element vectors and A is an N by N unit, or
nonunit, upper or lower triangular matrix, supplied in packed form.
UPLO
 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
 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
 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
 On entry, N specifies the order of the matrix
A; N must be at least 0; unchanged on
exit.

AP
 A vector of dimension at least ( ( N * (N+1) )/2
); on entry with UPLO = 'U' or 'u', the
array AP must contain the upper triangular matrix packed
sequentially, column by column, so that AP(1) contains
A(1,1), AP(2) and AP(3) contain
A(1,2) and A(2,2) respectively, and so on. Before
entry with UPLO = 'L' or 'l', the array
AP must contain the lower triangular matrix packed sequentially,
column by column, so that AP(1) contains A(1,1),
AP(2) and AP(3) contain A(2,1) and
A(3,1) respectively, and so on. When DIAG =
'U' or 'u', the diagonal elements of A are not
referenced, but are assumed to be unity; unchanged on exit.

X
 A vector of dimension at least (1 + (N1) *
abs(INCX) ); on 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
 On entry, INCX specifies the increment for the elements of
X; INCX must not be 0; unchanged on
exit.

No test for singularity or
nearsingularity is included in this routine. Such tests must be
performed before calling this routine.
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