LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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subroutine csyt01_3 | ( | character | uplo, |
integer | n, | ||
complex, dimension( lda, * ) | a, | ||
integer | lda, | ||
complex, dimension( ldafac, * ) | afac, | ||
integer | ldafac, | ||
complex, dimension( * ) | e, | ||
integer, dimension( * ) | ipiv, | ||
complex, dimension( ldc, * ) | c, | ||
integer | ldc, | ||
real, dimension( * ) | rwork, | ||
real | resid | ||
) |
CSYT01_3
CSYT01_3 reconstructs a symmetric indefinite matrix A from its block L*D*L' or U*D*U' factorization computed by CSYTRF_RK (or CSYTRF_BK) and computes the residual norm( C - A ) / ( N * norm(A) * EPS ), where C is the reconstructed matrix and EPS is the machine epsilon.
[in] | UPLO | UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix A is stored: = 'U': Upper triangular = 'L': Lower triangular |
[in] | N | N is INTEGER The number of rows and columns of the matrix A. N >= 0. |
[in] | A | A is COMPLEX array, dimension (LDA,N) The original symmetric matrix A. |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N) |
[in] | AFAC | AFAC is COMPLEX array, dimension (LDAFAC,N) Diagonal of the block diagonal matrix D and factors U or L as computed by CSYTRF_RK and 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 should be provided on entry 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. |
[in] | LDAFAC | LDAFAC is INTEGER The leading dimension of the array AFAC. LDAFAC >= max(1,N). |
[in] | E | E is COMPLEX array, dimension (N) 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. |
[in] | IPIV | IPIV is INTEGER array, dimension (N) The pivot indices from CSYTRF_RK (or CSYTRF_BK). |
[out] | C | C is COMPLEX array, dimension (LDC,N) |
[in] | LDC | LDC is INTEGER The leading dimension of the array C. LDC >= max(1,N). |
[out] | RWORK | RWORK is REAL array, dimension (N) |
[out] | RESID | RESID is REAL If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS ) If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS ) |
Definition at line 139 of file csyt01_3.f.