dgecon dgecov dgels dgesv dlange dlansy dpocon dposv dsyev

dgecon() def dgecon ( norm  , n  , a  , anorm    ) Condition number of a general matrix Purpose dgecon estimates the reciprocal of the condition number of a general real matrix A, in either the 1-norm or the infinity-norm, using the LU factorization computed by dgetrf, dgesv or dgesvx. 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))). Returns (rcond, info) rcond (float): The reciprocal of the condition number of the matrix A, computed as rcond = 1/(norm(A) * norm(inv(A))). info (int): = 0: Successful exit. = -1: The argument norm had an illegal value. (norm != '1', 'O' nor 'I') = -2: The argument n had an illegal value. (n < 0) = -3: The argument a is invalid. = -4: The argument anorm had an illegal value. (anorm < 0) Parameters [in] norm Specifies whether the 1-norm condition number or the infinity-norm condition number is required. = '1' or 'O': 1-norm = 'I': Infinity-norm [in] n Order of the matrix A. (n >= 0) (If n = 0, returns rcond = 1) [in] a Numpy ndarray (2-dimensional, float, n x n) Factors L and U from the factorization A = P*L*U as computed by dgetrf, dgesv or dgesvx. [in] anorm norm = '1' or 'O': The 1-norm of the original matrix A (anorm >= 0) norm = 'I': The infinity-norm of the original matrix A (anorm >= 0) Reference LAPACK Example Program See example of dgesv.