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## csyconvf_rook()

subroutine csyconvf_rook | ( | character | uplo,
|  | character | way,
|  | integer | n,
|  | complex, dimension( lda, * ) | a,
|  | integer | lda,
|  | complex, dimension( * ) | e,
|  | integer, dimension( * ) | ipiv,
|  | integer | info )

CSYCONVF_ROOK

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

Purpose:

      !> If parameter WAY = 'C':
      !> CSYCONVF_ROOK converts the factorization output format used in
      !> CSYTRF_ROOK provided on entry in parameter A into the factorization
      !> output format used in CSYTRF_RK (or CSYTRF_BK) that is stored
      !> on exit in parameters A and E. IPIV format for CSYTRF_ROOK and
      !> CSYTRF_RK (or CSYTRF_BK) is the same and is not converted.
      !>
      !> If parameter WAY = 'R':
      !> CSYCONVF_ROOK performs the conversion in reverse direction, i.e.
      !> converts the factorization output format used in CSYTRF_RK
      !> (or CSYTRF_BK) provided on entry in parameters A and E into
      !> the factorization output format used in CSYTRF_ROOK that is stored
      !> on exit in parameter A. IPIV format for CSYTRF_ROOK and
      !> CSYTRF_RK (or CSYTRF_BK) is the same and is not converted.
      !>
      !> CSYCONVF_ROOK can also convert in Hermitian matrix case, i.e. between
      !> formats used in CHETRF_ROOK and CHETRF_RK (or CHETRF_BK).
      !>

Parameters

  [in]

  UPLO

      !>          UPLO is CHARACTER*1
      !>          Specifies whether the details of the factorization are
      !>          stored as an upper or lower triangular matrix A.
      !>          = 'U':  Upper triangular
      !>          = 'L':  Lower triangular
      !>

  [in]

  WAY

      !>          WAY is CHARACTER*1
      !>          = 'C': Convert
      !>          = 'R': Revert
      !>

  [in]

  N

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

  [in,out]

  A

      !>          A is COMPLEX array, dimension (LDA,N)
      !>
      !>          1) If WAY ='C':
      !>
      !>          On entry, contains factorization details in format used in
      !>          CSYTRF_ROOK:
      !>            a) all elements of the symmetric block diagonal
      !>               matrix D on the diagonal of A and on superdiagonal
      !>               (or subdiagonal) of A, and
      !>            b) If UPLO = 'U': multipliers used to obtain factor U
      !>               in the superdiagonal part of A.
      !>               If UPLO = 'L': multipliers used to obtain factor L
      !>               in the superdiagonal part of A.
      !>
      !>          On exit, contains factorization details in format used in
      !>          CSYTRF_RK or CSYTRF_BK:
      !>            a) ONLY diagonal elements of the symmetric block diagonal
      !>               matrix D on the diagonal of A, i.e. D(k,k) = A(k,k);
      !>               (superdiagonal (or subdiagonal) elements of D
      !>                are stored on exit in array E), and
      !>            b) If UPLO = 'U': factor U in the superdiagonal part of A.
      !>               If UPLO = 'L': factor L in the subdiagonal part of A.
      !>
      !>          2) If WAY = 'R':
      !>
      !>          On entry, contains factorization details in format used in
      !>          CSYTRF_RK or CSYTRF_BK:
      !>            a) ONLY diagonal elements of the symmetric block diagonal
      !>               matrix D on the diagonal of A, i.e. D(k,k) = A(k,k);
      !>               (superdiagonal (or subdiagonal) elements of D
      !>                are stored on exit in array E), and
      !>            b) If UPLO = 'U': factor U in the superdiagonal part of A.
      !>               If UPLO = 'L': factor L in the subdiagonal part of A.
      !>
      !>          On exit, contains factorization details in format used in
      !>          CSYTRF_ROOK:
      !>            a) all elements of the symmetric block diagonal
      !>               matrix D on the diagonal of A and on superdiagonal
      !>               (or subdiagonal) of A, and
      !>            b) If UPLO = 'U': multipliers used to obtain factor U
      !>               in the superdiagonal part of A.
      !>               If UPLO = 'L': multipliers used to obtain factor L
      !>               in the superdiagonal part of A.
      !>

  [in]

  LDA

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

  [in,out]

  E

      !>          E is COMPLEX array, dimension (N)
      !>
      !>          1) If WAY ='C':
      !>
      !>          On entry, just a workspace.
      !>
      !>          On exit, contains the superdiagonal (or subdiagonal)
      !>          elements of the symmetric block diagonal matrix D
      !>          with 1-by-1 or 2-by-2 diagonal blocks, where
      !>          If UPLO = 'U': E(i) = D(i-1,i), i=2:N, E(1) is set to 0;
      !>          If UPLO = 'L': E(i) = D(i+1,i), i=1:N-1, E(N) is set to 0.
      !>
      !>          2) If WAY = 'R':
      !>
      !>          On entry, contains the superdiagonal (or subdiagonal)
      !>          elements of the symmetric block diagonal matrix D
      !>          with 1-by-1 or 2-by-2 diagonal blocks, where
      !>          If UPLO = 'U': E(i) = D(i-1,i),i=2:N, E(1) not referenced;
      !>          If UPLO = 'L': E(i) = D(i+1,i),i=1:N-1, E(N) not referenced.
      !>
      !>          On exit, is not changed
      !>

  [in]

  IPIV

      !>          IPIV is INTEGER array, dimension (N)
      !>          On entry, details of the interchanges and the block
      !>          structure of D as determined:
      !>          1) by CSYTRF_ROOK, if WAY ='C';
      !>          2) by CSYTRF_RK (or CSYTRF_BK), if WAY ='R'.
      !>          The IPIV format is the same for all these routines.
      !>
      !>          On exit, is not changed.
      !>

  [out]

  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.

Contributors:

      !>
      !>  November 2017,  Igor Kozachenko,
      !>                  Computer Science Division,
      !>                  University of California, Berkeley
      !>
      !>