Zpocon Zpotrf Zpotri Zpotrs Zppcon Zpptrf Zpptri Zpptrs

Zppcon() Sub Zppcon ( Uplo As  String, N As  Long, Ap() As  Complex, ANorm As  Double, RCond As  Double, Info As  Long  ) Condition number of a Hermitian positive definite matrix in packed form Purpose This routine estimates the reciprocal of the condition number (in the 1-norm) of a Hermitian positive definite packed matrix using the Cholesky factorization A = U^H*U or A = L*L^H computed by Zpptrf. An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCond = 1 / (norm(A) * norm(inv(A))). Parameters [in] Uplo Specifies whether the factor U or L is stored. = "U": Upper triangular factor U from the Cholesky factorization A = U^T*U. = "L": Lower triangular factor L from the Cholesky factorization A = L*L^T. [in] N Order of the matrix A. (N >= 0) (if N = 0, returns RCond = 1) [in] Ap() Array Ap(LAp - 1) (LAp >= N(N + 1)/2) The triangular factor U or L in packed form from the Cholesky factorization A = U^H*U or A = L*L^H, as computed by Zpptrf. [in] ANorm The 1-norm (or infinity-norm) of the symmetric matrix A. (ANorm >= 0) [out] RCond 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] Info = 0: Successful exit. = -1: The argument Uplo had an illegal value. (Uplo <> "U" nor "L") = -2: The argument N had an illegal value. (N < 0) = -3: The argument Ap() is invalid. = -4: The argument ANorm had an illegal value. (ANorm < 0) Reference LAPACK Example Program See example of Zppsv.