Note: this is a BLAS routine and is not in libslatec.a
*DECK STPSV
SUBROUTINE STPSV (UPLO, TRANS, DIAG, N, AP, X, INCX)
C***BEGIN PROLOGUE STPSV
C***PURPOSE Solve one of the systems of equations.
C***LIBRARY SLATEC (BLAS)
C***CATEGORY D1B4
C***TYPE SINGLE PRECISION (STPSV-S, DTPSV-D, CTPSV-C)
C***KEYWORDS LEVEL 2 BLAS, LINEAR ALGEBRA
C***AUTHOR Dongarra, J. J., (ANL)
C Du Croz, J., (NAG)
C Hammarling, S., (NAG)
C Hanson, R. J., (SNLA)
C***DESCRIPTION
C
C STPSV solves one of the systems of equations
C
C A*x = b, or A'*x = b,
C
C where b and x are n element vectors and A is an n by n unit, or
C non-unit, upper or lower triangular matrix, supplied in packed form.
C
C No test for singularity or near-singularity is included in this
C routine. Such tests must be performed before calling this routine.
C
C Parameters
C ==========
C
C UPLO - CHARACTER*1.
C On entry, UPLO specifies whether the matrix is an upper or
C lower triangular matrix as follows:
C
C UPLO = 'U' or 'u' A is an upper triangular matrix.
C
C UPLO = 'L' or 'l' A is a lower triangular matrix.
C
C Unchanged on exit.
C
C TRANS - CHARACTER*1.
C On entry, TRANS specifies the equations to be solved as
C follows:
C
C TRANS = 'N' or 'n' A*x = b.
C
C TRANS = 'T' or 't' A'*x = b.
C
C TRANS = 'C' or 'c' A'*x = b.
C
C Unchanged on exit.
C
C DIAG - CHARACTER*1.
C On entry, DIAG specifies whether or not A is unit
C triangular as follows:
C
C DIAG = 'U' or 'u' A is assumed to be unit triangular.
C
C DIAG = 'N' or 'n' A is not assumed to be unit
C triangular.
C
C Unchanged on exit.
C
C N - INTEGER.
C On entry, N specifies the order of the matrix A.
C N must be at least zero.
C Unchanged on exit.
C
C AP - REAL array of DIMENSION at least
C ( ( n*( n + 1))/2).
C Before entry with UPLO = 'U' or 'u', the array AP must
C contain the upper triangular matrix packed sequentially,
C column by column, so that AP( 1 ) contains a( 1, 1 ),
C AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 )
C respectively, and so on.
C Before entry with UPLO = 'L' or 'l', the array AP must
C contain the lower triangular matrix packed sequentially,
C column by column, so that AP( 1 ) contains a( 1, 1 ),
C AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 )
C respectively, and so on.
C Note that when DIAG = 'U' or 'u', the diagonal elements of
C A are not referenced, but are assumed to be unity.
C Unchanged on exit.
C
C X - REAL array of dimension at least
C ( 1 + ( n - 1 )*abs( INCX ) ).
C Before entry, the incremented array X must contain the n
C element right-hand side vector b. On exit, X is overwritten
C with the solution vector x.
C
C INCX - INTEGER.
C On entry, INCX specifies the increment for the elements of
C X. INCX must not be zero.
C Unchanged on exit.
C
C***REFERENCES Dongarra, J. J., Du Croz, J., Hammarling, S., and
C Hanson, R. J. An extended set of Fortran basic linear
C algebra subprograms. ACM TOMS, Vol. 14, No. 1,
C pp. 1-17, March 1988.
C***ROUTINES CALLED LSAME, XERBLA
C***REVISION HISTORY (YYMMDD)
C 861022 DATE WRITTEN
C 910605 Modified to meet SLATEC prologue standards. Only comment
C lines were modified. (BKS)
C***END PROLOGUE STPSV