getc2(3)

NAME
getc2 - getc2: triangular factor, with complete pivoting

SYNOPSIS

  Functions

subroutine cgetc2 (n, a, lda, ipiv, jpiv, info)
CGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.
subroutine dgetc2 (n, a, lda, ipiv, jpiv, info)
DGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.
subroutine sgetc2 (n, a, lda, ipiv, jpiv, info)
SGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.
subroutine zgetc2 (n, a, lda, ipiv, jpiv, info)
ZGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

Detailed Description

Function Documentation

  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.

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
    N

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

    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.
    !>

    LDA

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

    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).
    !>

    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).
    !>

    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.

  subroutine dgetc2 (integer n, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, integer, dimension( * ) jpiv, integer info)

DGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

Purpose:

    !>
    !> DGETC2 computes an LU factorization with 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 the Level 2 BLAS algorithm.
    !>

Parameters
    N

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

    A

    !>          A is DOUBLE PRECISION array, dimension (LDA, N)
    !>          On entry, the n-by-n matrix A 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, i.e., giving a nonsingular perturbed system.
    !>

    LDA

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

    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).
    !>

    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).
    !>

    INFO

    !>          INFO is INTEGER
    !>           = 0: successful exit
    !>           > 0: if INFO = k, U(k, k) is likely to produce overflow if
    !>                we try 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.

  subroutine sgetc2 (integer n, real, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, integer, dimension( * ) jpiv, integer info)

SGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

Purpose:

    !>
    !> SGETC2 computes an LU factorization with 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 the Level 2 BLAS algorithm.
    !>

Parameters
    N

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

    A

    !>          A is REAL array, dimension (LDA, N)
    !>          On entry, the n-by-n matrix A 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, i.e., giving a nonsingular perturbed system.
    !>

    LDA

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

    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).
    !>

    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).
    !>

    INFO

    !>          INFO is INTEGER
    !>           = 0: successful exit
    !>           > 0: if INFO = k, U(k, k) is likely to produce overflow if
    !>                we try 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.

  subroutine zgetc2 (integer n, complex*16, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, integer, dimension( * ) jpiv, integer info)

ZGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

Purpose:

    !>
    !> ZGETC2 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
    N

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

    A

    !>          A is COMPLEX*16 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.
    !>

    LDA

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

    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).
    !>

    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).
    !>

    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.

Author

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