SRC/ssyconvf.f(3)          Library Functions Manual          SRC/ssyconvf.f(3)

NAME
       SRC/ssyconvf.f

SYNOPSIS
   Functions/Subroutines
       subroutine ssyconvf (uplo, way, n, a, lda, e, ipiv, info)
           SSYCONVF

Function/Subroutine Documentation
   subroutine ssyconvf (character uplo, character way, integer n, real,
       dimension( lda, * ) a, integer lda, real, dimension( * ) e, integer,
       dimension( * ) ipiv, integer info)
       SSYCONVF

       Purpose:


            If parameter WAY = 'C':
            SSYCONVF converts the factorization output format used in
            SSYTRF 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. It also converts in place details of
            the interchanges stored in IPIV from the format used in SSYTRF into
            the format used in SSYTRF_RK (or SSYTRF_BK).

            If parameter WAY = 'R':
            SSYCONVF 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 that is stored
            on exit in parameter A. It also converts in place details of
            the interchanges stored in IPIV from the format used in SSYTRF_RK
            (or SSYTRF_BK) into the format used in SSYTRF.

       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:
                       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:
                       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)

                     1) If WAY ='C':
                     On entry, details of the interchanges and the block
                     structure of D in the format used in SSYTRF.
                     On exit, details of the interchanges and the block
                     structure of D in the format used in SSYTRF_RK
                     ( or SSYTRF_BK).

                     1) If WAY ='R':
                     On entry, details of the interchanges and the block
                     structure of D in the format used in SSYTRF_RK
                     ( or SSYTRF_BK).
                     On exit, details of the interchanges and the block
                     structure of D in the format used in SSYTRF.

           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 205 of file ssyconvf.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0               SRC/ssyconvf.f(3)