SRC/ssyconvf_rook.f(3)

NAME
SRC/ssyconvf_rook.f

SYNOPSIS

  Functions/Subroutines
subroutine ssyconvf_rook (uplo, way, n, a, lda, e, ipiv, info)
SSYCONVF_ROOK

Function/Subroutine Documentation

  subroutine ssyconvf_rook (character uplo, character way, integer n, real, dimension( lda, * ) a, integer lda, real, dimension( * ) e, integer, dimension( * ) ipiv, integer info)

SSYCONVF_ROOK

Purpose:

     If parameter WAY = 'C':
     SSYCONVF_ROOK converts the factorization output format used in
     SSYTRF_ROOK provided on entry in parameter A into the factorization
     output format used in SSYTRF_RK (or SSYTRF_BK) that is stored
     on exit in parameters A and E. IPIV format for SSYTRF_ROOK and
     SSYTRF_RK (or SSYTRF_BK) is the same and is not converted.
     If parameter WAY = 'R':
     SSYCONVF_ROOK performs the conversion in reverse direction, i.e.
     converts the factorization output format used in SSYTRF_RK
     (or SSYTRF_BK) provided on entry in parameters A and E into
     the factorization output format used in SSYTRF_ROOK that is stored
     on exit in parameter A. IPIV format for SSYTRF_ROOK and
     SSYTRF_RK (or SSYTRF_BK) is the same and is not converted.

Parameters
    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

    WAY

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

    N

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

    A

              A is REAL array, dimension (LDA,N)
              1) If WAY ='C':
              On entry, contains factorization details in format used in
              SSYTRF_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
              SSYTRF_RK or SSYTRF_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
              SSYTRF_RK or SSYTRF_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
              SSYTRF_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.

    LDA

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

    E

              E is REAL 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

    IPIV

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

    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

Definition at line 196 of file ssyconvf_rook.f.

Author

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