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
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