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

NAME
       SRC/spttrf.f

SYNOPSIS
   Functions/Subroutines
       subroutine spttrf (n, d, e, info)
           SPTTRF

Function/Subroutine Documentation
   subroutine spttrf (integer n, real, dimension( * ) d, real, dimension( * )
       e, integer info)
       SPTTRF

       Purpose:


            SPTTRF computes the L*D*L**T factorization of a real symmetric
            positive definite tridiagonal matrix A.  The factorization may also
            be regarded as having the form A = U**T*D*U.

       Parameters
           N

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

           D

                     D is REAL array, dimension (N)
                     On entry, the n diagonal elements of the tridiagonal matrix
                     A.  On exit, the n diagonal elements of the diagonal matrix
                     D from the L*D*L**T factorization of A.

           E

                     E is REAL array, dimension (N-1)
                     On entry, the (n-1) subdiagonal elements of the tridiagonal
                     matrix A.  On exit, the (n-1) subdiagonal elements of the
                     unit bidiagonal factor L from the L*D*L**T factorization of A.
                     E can also be regarded as the superdiagonal of the unit
                     bidiagonal factor U from the U**T*D*U factorization of A.

           INFO

                     INFO is INTEGER
                     = 0: successful exit
                     < 0: if INFO = -k, the k-th argument had an illegal value
                     > 0: if INFO = k, the leading principal minor of order k
                          is not positive; if k < N, the factorization could not
                          be completed, while if k = N, the factorization was
                          completed, but D(N) <= 0.

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 90 of file spttrf.f.

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

LAPACK                          Version 3.12.0                 SRC/spttrf.f(3)