subroutine csyconvf (UPLO, WAY, N, A, LDA, E, IPIV, INFO)
CSYCONVF
CSYCONVF
Purpose:
If parameter WAY = 'C': CSYCONVF converts the factorization output format used in CSYTRF 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. It also coverts in place details of the intechanges stored in IPIV from the format used in CSYTRF into the format used in CSYTRF_RK (or CSYTRF_BK). If parameter WAY = 'R': CSYCONVF 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 that is stored on exit in parameter A. It also coverts in place details of the intechanges stored in IPIV from the format used in CSYTRF_RK (or CSYTRF_BK) into the format used in CSYTRF. CSYCONVF can also convert in Hermitian matrix case, i.e. between formats used in CHETRF and CHETRF_RK (or CHETRF_BK).
Parameters:
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 COMPLEX array, dimension (LDA,N)
1) If WAY ='C':
On entry, contains factorization details in format used in
CSYTRF:
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:
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 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
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 CSYTRF.
On exit, details of the interchanges and the block
structure of D in the format used in CSYTRF_RK
( or CSYTRF_BK).
1) If WAY ='R':
On entry, details of the interchanges and the block
structure of D in the format used in CSYTRF_RK
( or CSYTRF_BK).
On exit, details of the interchanges and the block
structure of D in the format used in CSYTRF.
INFO
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
Author:
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
Contributors:
November 2017, Igor Kozachenko,
Computer Science Division,
University of California, Berkeley
Definition at line 211 of file csyconvf.f.
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