SRC/stptrs.f(3)            Library Functions Manual            SRC/stptrs.f(3)

NAME
       SRC/stptrs.f

SYNOPSIS
   Functions/Subroutines
       subroutine stptrs (uplo, trans, diag, n, nrhs, ap, b, ldb, info)
           STPTRS

Function/Subroutine Documentation
   subroutine stptrs (character uplo, character trans, character diag, integer
       n, integer nrhs, real, dimension( * ) ap, real, dimension( ldb, * ) b,
       integer ldb, integer info)
       STPTRS

       Purpose:


           !>
           !> STPTRS solves a triangular system of the form
           !>
           !>    A * X = B  or  A**T * X = B,
           !>
           !> where A is a triangular matrix of order N stored in packed format, and B is an N-by-NRHS matrix.
           !>
           !> This subroutine verifies that A is nonsingular, but callers should note that only exact
           !> singularity is detected. It is conceivable for one or more diagonal elements of A to be
           !> subnormally tiny numbers without this subroutine signalling an error.
           !>
           !> If a possible loss of numerical precision due to near-singular matrices is a concern, the
           !> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
           !>

       Parameters
           UPLO

           !>          UPLO is CHARACTER*1
           !>          = 'U':  A is upper triangular;
           !>          = 'L':  A is lower triangular.
           !>

           TRANS

           !>          TRANS is CHARACTER*1
           !>          Specifies the form of the system of equations:
           !>          = 'N':  A * X = B  (No transpose)
           !>          = 'T':  A**T * X = B  (Transpose)
           !>          = 'C':  A**H * X = B  (Conjugate transpose = Transpose)
           !>

           DIAG

           !>          DIAG is CHARACTER*1
           !>          = 'N':  A is non-unit triangular;
           !>          = 'U':  A is unit triangular.
           !>

           N

           !>          N is INTEGER
           !>          The order of the matrix A.  N >= 0.
           !>

           NRHS

           !>          NRHS is INTEGER
           !>          The number of right hand sides, i.e., the number of columns
           !>          of the matrix B.  NRHS >= 0.
           !>

           AP

           !>          AP is REAL array, dimension (N*(N+1)/2)
           !>          The upper or lower triangular matrix A, packed columnwise in
           !>          a linear array.  The j-th column of A is stored in the array
           !>          AP as follows:
           !>          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
           !>          if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.
           !>

           B

           !>          B is REAL array, dimension (LDB,NRHS)
           !>          On entry, the right hand side matrix B.
           !>          On exit, if INFO = 0, the solution matrix X.
           !>

           LDB

           !>          LDB is INTEGER
           !>          The leading dimension of the array B.  LDB >= max(1,N).
           !>

           INFO

           !>          INFO is INTEGER
           !>          = 0:  successful exit
           !>          < 0:  if INFO = -i, the i-th argument had an illegal value
           !>          > 0:  if INFO = i, the i-th diagonal element of A is exactly zero,
           !>                indicating that the matrix is singular and the
           !>                solutions X have not been computed.
           !>

       Author
           Univ. of Tennessee


           Univ. of California Berkeley


           Univ. of Colorado Denver


           NAG Ltd.

       Definition at line 134 of file stptrs.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/stptrs.f(3)