zpocon zpotrf zpotri zpotrs zppcon zpptrf zpptri zpptrs

zppcon() void zppcon ( char  uplo, int  n, doublecomplex  ap[], double  anorm, double *  rcond, doublecomplex  work[], double  rwork[], int *  info  ) 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 / (anorm * 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^H*U. = 'L': Lower triangular factor L from the Cholesky factorization A = L*L^H. [in] n Order of the matrix A. (n >= 0) (If n = 0, returns rcond = 1) [in] ap[] Array ap[lap] (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 Hermitian 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] work[] Array work[lwork] (lwork >= 2*n) Work array. [out] rwork[] Array rwork[lrwork] (lrwork >= n) Work array. [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) = -4: The argument anorm had an illegal value (anorm < 0) Reference LAPACK