== or =:=) constraints Constraints; otherwise fails. Example:
?- taylor_contractor({X**4-4*X**3+4*X**2-4*X+3==0},T).
T = cf_contractor([X], [_A]),
X::real(-1.509169756145379, 4.18727500493995),
_A::real(-1.0Inf, 1.0Inf).
Use the contractor with cf_solve to search for solutions, as in:
?- X::real,taylor_contractor({X**4-4*X**3+4*X**2-4*X+3==0},T), cf_solve(T).
T = cf_contractor([X], [_A]),
X:: 1.000000000...,
_A::real(-1.0Inf, 1.0Inf) ;
T = cf_contractor([X], [_A]),
X:: 3.00000000...,
_A::real(-1.0Inf, 1.0Inf) ;
false.
Multiple equality constraints are supported, as in this example of the Broyden banded problem (N=2):
?- taylor_contractor({2*X1+5*X1**3+1==X2*(1+X2), 2*X2+5*X2**3+1==X1*(1+X1)},T), cf_solve(T).
T = cf_contractor([X2, X1], [_A, _B]),
X1:: -0.42730462...,
X2:: -0.42730462...,
_B::real(-1.0Inf, 1.0Inf),
_A::real(-1.0Inf, 1.0Inf) ;
false.
Centre form contractors can converge faster than the general purpose builtin fixed point iteration provided by solve/1.
cf_solve/1