SRC/ssyconvf_rook.f(3)     Library Functions Manual     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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LAPACK                          Version 3.12.0          SRC/ssyconvf_rook.f(3)