diff options
| -rw-r--r-- | sumofsquares/problems.py | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/sumofsquares/problems.py b/sumofsquares/problems.py index 4256642..4482c1e 100644 --- a/sumofsquares/problems.py +++ b/sumofsquares/problems.py @@ -174,7 +174,15 @@ class SOSProblem(Problem): return internal_prob.solve(verbose) def apply(self, state: ExpressionState) -> tuple[ExpressionState, InternalSOSProblem]: - """ Convert to internal SOS problem by applying state to the expressions. """ + """ + Convert to internal SOS problem by applying state to the expressions. + + **Technical Note:** The internal SOS problem may only constraints that + are linear in the optimization variables, hence, conversion of + polynomial equality / non-negativity constraints are done here. + Likewise the cost function must also be reduced to quadratic expression + here. + """ constraints: list[Constraint[PolyMatrixMixin]] = [] state, cost = self.cost.apply(state) @@ -213,6 +221,7 @@ class SOSProblem(Problem): elif isinstance(c, NonNegative): if c.domain: + # See also class canon.PutinarPSatz raise ValueError(f"Cannot convert non-negativity constraint nr. {i} " "to conic constraint. Domain restricted non-negativity " "must be preprocessed by using a Positivstellensatz!") @@ -270,8 +279,6 @@ class InternalSOSProblem(Problem): def to_conic_problem(self) -> ConicProblem: """ Conver the SOS problem into a Conic program. - - TODO: docstring """ cost = poly.to_affine(self.cost) if cost.degree > 2: @@ -327,6 +334,8 @@ class InternalSOSProblem(Problem): nrows, ncols = constr.shape if constr.degree > 1: + # If this error occurs an it is not the user's fault, there is a bug in + # SOSProblem.apply raise ValueError("To convert to conic constraints must be linear or affine " f"but {str(c.expression)} has degree {constr.degree}.") |