LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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subroutine cspcon | ( | character | uplo, |
integer | n, | ||
complex, dimension( * ) | ap, | ||
integer, dimension( * ) | ipiv, | ||
real | anorm, | ||
real | rcond, | ||
complex, dimension( * ) | work, | ||
integer | info | ||
) |
CSPCON
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CSPCON estimates the reciprocal of the condition number (in the 1-norm) of a complex symmetric packed matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by CSPTRF. An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
[in] | UPLO | UPLO is CHARACTER*1 Specifies whether the details of the factorization are stored as an upper or lower triangular matrix. = 'U': Upper triangular, form is A = U*D*U**T; = 'L': Lower triangular, form is A = L*D*L**T. |
[in] | N | N is INTEGER The order of the matrix A. N >= 0. |
[in] | AP | AP is COMPLEX array, dimension (N*(N+1)/2) The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CSPTRF, stored as a packed triangular matrix. |
[in] | IPIV | IPIV is INTEGER array, dimension (N) Details of the interchanges and the block structure of D as determined by CSPTRF. |
[in] | ANORM | ANORM is REAL The 1-norm of the original matrix A. |
[out] | RCOND | RCOND is REAL The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1-norm of inv(A) computed in this routine. |
[out] | WORK | WORK is COMPLEX array, dimension (2*N) |
[out] | INFO | INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value |
Definition at line 117 of file cspcon.f.