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Technical Reference: Base Operating System and Extensions, Volume 2
STPSV, DTPSV, CTPSV, or ZTPSV Subroutine
Purpose
Solves systems of equations.
Library
BLAS Library (libblas.a)
FORTRAN Syntax
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(*)
Description
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 non-unit, upper or lower triangular matrix,
supplied in packed form.
No test for singularity or near-singularity is included
in this routine. Such tests must be performed before calling this routine.
Parameters
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 + (N-1)
* abs(INCX) ); on entry, the incremented array X must contain the N element right-hand
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. |
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