stpsv.f man page

stpsv.f —

Synopsis

Functions/Subroutines

subroutine stpsv (UPLO, TRANS, DIAG, N, AP, X, INCX)
STPSV

Function/Subroutine Documentation

subroutine stpsv (characterUPLO, characterTRANS, characterDIAG, integerN, real, dimension(*)AP, real, dimension(*)X, integerINCX)

STPSV Purpose:

STPSV  solves one of the systems of equations

   A*x = b,   or   A**T*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

UPLO is 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.

TRANS

TRANS is 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**T*x = b.

    TRANS = 'C' or 'c'   A**T*x = b.

DIAG

DIAG is 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.

N

N is INTEGER
 On entry, N specifies the order of the matrix A.
 N must be at least zero.

AP

AP is REAL array of DIMENSION at least
 ( ( n*( n + 1 ) )/2 ).
 Before 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.
 Note that when  DIAG = 'U' or 'u', the diagonal elements of
 A are not referenced, but are assumed to be unity.

X

X is REAL array of dimension at least
 ( 1 + ( n - 1 )*abs( INCX ) ).
 Before 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

INCX is INTEGER
 On entry, INCX specifies the increment for the elements of
 X. INCX must not be zero.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Further Details:

Level 2 Blas routine.

-- Written on 22-October-1986.
   Jack Dongarra, Argonne National Lab.
   Jeremy Du Croz, Nag Central Office.
   Sven Hammarling, Nag Central Office.
   Richard Hanson, Sandia National Labs.

Definition at line 145 of file stpsv.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

stpsv(3) is an alias of stpsv.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK