scipy.linalg.lapack.sgtcon

scipy.linalg.lapack.sgtcon(dl, d, du, du2, ipiv, anorm, norm='1') = <flapack function sgtcon>

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

Parameters:

dlndarray

Multipliers defining L, as returned by gttrf.

dndarray

Diagonal of U, as returned by gttrf.

dundarray

First superdiagonal of U, as returned by gttrf.

du2ndarray

Second superdiagonal of U, as returned by gttrf.

ipivndarray

Pivot indices from gttrf, 1-based.

anormfloat

Norm of the original matrix, in the norm selected by norm.

normstr, optional

'1' or 'O' for the 1-norm, 'I' for the infinity norm. Default is '1'.

Returns:

rcondfloat

Estimate of the reciprocal condition number.

infoint

0 on success; if negative, the -info-th argument had an illegal value.