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## dgesc2()

subroutine dgesc2 | ( | integer | n,
|  | double precision, dimension( lda, * ) | a,
|  | integer | lda,
|  | double precision, dimension( * ) | rhs,
|  | integer, dimension( * ) | ipiv,
|  | integer, dimension( * ) | jpiv,
|  | double precision | scale )

DGESC2 solves a system of linear equations using the LU factorization with complete pivoting computed by sgetc2.

Download DGESC2 + dependencies [TGZ] [ZIP] [TXT]

Purpose:

      !>
      !> DGESC2 solves a system of linear equations
      !>
      !>           A * X = scale* RHS
      !>
      !> with a general N-by-N matrix A using the LU factorization with
      !> complete pivoting computed by DGETC2.
      !>

Parameters

  [in]

  N

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

  [in]

  A

      !>          A is DOUBLE PRECISION array, dimension (LDA,N)
      !>          On entry, the  LU part of the factorization of the n-by-n
      !>          matrix A computed by DGETC2:  A = P * L * U * Q
      !>

  [in]

  LDA

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

  [in,out]

  RHS

      !>          RHS is DOUBLE PRECISION array, dimension (N).
      !>          On entry, the right hand side vector b.
      !>          On exit, the solution vector X.
      !>

  [in]

  IPIV

      !>          IPIV is INTEGER array, dimension (N).
      !>          The pivot indices; for 1 <= i <= N, row i of the
      !>          matrix has been interchanged with row IPIV(i).
      !>

  [in]

  JPIV

      !>          JPIV is INTEGER array, dimension (N).
      !>          The pivot indices; for 1 <= j <= N, column j of the
      !>          matrix has been interchanged with column JPIV(j).
      !>

  [out]

  SCALE

      !>          SCALE is DOUBLE PRECISION
      !>          On exit, SCALE contains the scale factor. SCALE is chosen
      !>          0 <= SCALE <= 1 to prevent overflow in the solution.
      !>

Author
  Univ. of Tennessee
  Univ. of California Berkeley
  Univ. of Colorado Denver
  NAG Ltd.

Contributors:
  Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden.