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## cgetc2()

subroutine cgetc2 | ( | integer | n,
|  | complex, dimension( lda, * ) | a,
|  | integer | lda,
|  | integer, dimension( * ) | ipiv,
|  | integer, dimension( * ) | jpiv,
|  | integer | info )

CGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

Download CGETC2 + dependencies [TGZ] [ZIP] [TXT]

Purpose:

      !>
      !> CGETC2 computes an LU factorization, using complete pivoting, of the
      !> n-by-n matrix A. The factorization has the form A = P * L * U * Q,
      !> where P and Q are permutation matrices, L is lower triangular with
      !> unit diagonal elements and U is upper triangular.
      !>
      !> This is a level 1 BLAS version of the algorithm.
      !>

Parameters

  [in]

  N

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

  [in,out]

  A

      !>          A is COMPLEX array, dimension (LDA, N)
      !>          On entry, the n-by-n matrix to be factored.
      !>          On exit, the factors L and U from the factorization
      !>          A = P*L*U*Q; the unit diagonal elements of L are not stored.
      !>          If U(k, k) appears to be less than SMIN, U(k, k) is given the
      !>          value of SMIN, giving a nonsingular perturbed system.
      !>

  [in]

  LDA

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

  [out]

  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).
      !>

  [out]

  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]

  INFO

      !>          INFO is INTEGER
      !>           = 0: successful exit
      !>           > 0: if INFO = k, U(k, k) is likely to produce overflow if
      !>                one tries to solve for x in Ax = b. So U is perturbed
      !>                to avoid the overflow.
      !>

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.