Basis Factorization Controls¶

class ecyglpki.FactorizationControls¶

The basis factorization control parameter object

>>> p = Problem()
>>> r = FactorizationControls(p)

eps_tol¶

Tolerance below which numbers are replaced by zero, a Real number

>>> r.eps_tol  # the GLPK default
2.220446049250313e-16
>>> r.eps_tol = 0.1
>>> r.eps_tol
0.1

nfs_max¶

Maximal number of additional row-like factors, an int

(Used only when type contains 'Forrest-Tomlin'.)

>>> r.nfs_max  # the GLPK default
100
>>> r.nfs_max = 200
>>> r.nfs_max
200

nrs_max¶

Maximal number of additional row and columns, an int

(Used only when type contains 'Bartels-Golub' or 'Givens'.)

>>> r.nrs_max  # the GLPK default
70
>>> r.nrs_max = 7
>>> r.nrs_max
7

piv_lim¶

Number of pivot candidates that need to be considered, an int ≥1

>>> r.piv_lim  # the GLPK default
4
>>> r.piv_lim = 3
>>> r.piv_lim
3

piv_tol¶

Markowitz threshold pivoting tolerance, a Real number

(Value must lie between 0 and 1.)

>>> r.piv_tol  # the GLPK default
0.1
>>> r.piv_tol = 0.5
>>> r.piv_tol
0.5

suhl¶

Whether to use Suhl heuristic, a bool

>>> r.suhl  # the GLPK default
True
>>> r.suhl = False
>>> r.suhl
False

type¶

The basis factorization type, str pairs

Possible first components:

Possible second components

'Forrest-Tomlin': Forrest–Tomlin update applied to U (only with plain LU factorization)
'Bartels-Golub': Bartels–Golub update applied to Schur complement
'Givens': Givens rotation update applied to Schur complement

>>> r.type  # the GLPK default
('LU', 'Forrest-Tomlin')
>>> r.type = ('BTLU', 'Bartels-Golub')
>>> r.type
('BTLU', 'Bartels-Golub')