scipy.linalg.lapack.cgttrf

scipy.linalg.lapack.cgttrf(dl, d, du, overwrite_dl=0, overwrite_d=0, overwrite_du=0) = <flapack function cgttrf>

Compute the LU factorization of a tridiagonal matrix with partial pivoting (LAPACK cgttrf).

Parameters:

dlndarray

Subdiagonal elements, length n - 1.

dndarray

Diagonal elements, length n.

dundarray

Superdiagonal elements, length n - 1.

overwrite_dlint, optional

If nonzero, dl may be overwritten in place. Default is 0.

overwrite_dint, optional

If nonzero, d may be overwritten in place. Default is 0.

overwrite_duint, optional

If nonzero, du may be overwritten in place. Default is 0.

Returns:

dlndarray

Multipliers defining L.

dndarray

Diagonal of U.

dundarray

First superdiagonal of U.

du2ndarray

Second superdiagonal of U, length n - 2.

ipivndarray

Pivot indices, 1-based – unlike getrf, which returns them 0-based. gttrs, gtcon and gtsvx take them exactly as returned.

infoint

0 on success; if negative, the -info-th argument had an illegal value; if positive, u[info-1, info-1] is exactly zero and the factor is singular.