SRC/dsytrs2.f(3)

NAME
SRC/dsytrs2.f

SYNOPSIS

  Functions/Subroutines
subroutine dsytrs2 (uplo, n, nrhs, a, lda, ipiv, b, ldb, work, info)
DSYTRS2

Function/Subroutine Documentation

  subroutine dsytrs2 (character uplo, integer n, integer nrhs, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( * ) work, integer info)

DSYTRS2

Purpose:

     DSYTRS2 solves a system of linear equations A*X = B with a real
     symmetric matrix A using the factorization A = U*D*U**T or
     A = L*D*L**T computed by DSYTRF and converted by DSYCONV.

Parameters
    UPLO

              UPLO is CHARACTER*1
              Specifies whether the details of the factorization are stored
              as an upper or lower triangular matrix.
              = 'U':  Upper triangular, form is A = U*D*U**T;
              = 'L':  Lower triangular, form is A = L*D*L**T.

    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.

    A

              A is DOUBLE PRECISION array, dimension (LDA,N)
              The block diagonal matrix D and the multipliers used to
              obtain the factor U or L as computed by DSYTRF.
              Note that A is input / output. This might be counter-intuitive,
              and one may think that A is input only. A is input / output. This
              is because, at the start of the subroutine, we permute A in a
              'better' form and then we permute A back to its original form at
              the end.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,N).

    IPIV

              IPIV is INTEGER array, dimension (N)
              Details of the interchanges and the block structure of D
              as determined by DSYTRF.

    B

              B is DOUBLE PRECISION array, dimension (LDB,NRHS)
              On entry, the right hand side matrix B.
              On exit, the solution matrix X.

    LDB

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

    WORK

              WORK is DOUBLE PRECISION array, dimension (N)

    INFO

              INFO is INTEGER
              = 0:  successful exit
              < 0:  if INFO = -i, the i-th argument had an illegal value

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 130 of file dsytrs2.f.

Author

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