`scipy.linalg._flapack:cgtcon`

Signature

def cgtcon(dl, d, du, du2, ipiv, anorm, norm = 1)

Estimate the reciprocal condition number of a tridiagonal matrix from its gttrf factorization (LAPACK cgtcon).

dl : ndarray: Multipliers defining L, as returned by gttrf.
d : ndarray: Diagonal of U, as returned by gttrf.
du : ndarray: First superdiagonal of U, as returned by gttrf.
du2 : ndarray: Second superdiagonal of U, as returned by gttrf.
ipiv : ndarray: Pivot indices from gttrf, 1-based.
anorm : float: Norm of the original matrix, in the norm selected by norm.
norm : str, optional: '1' or 'O' for the 1-norm, 'I' for the infinity norm. Default is '1'.

rcond : float: Estimate of the reciprocal condition number.
info : int: 0 on success; if negative, the -info-th argument had an illegal value.