Function

class Function

General mathematical function of decision variables.

__add__(rhs: ToFunction) → Function

Addition

__copy__() → Function
__deepcopy__(_memo: Any) → Function
__eq__(other: ToFunction) → Constraint

Create an equality constraint: self == other → Constraint with EqualToZero

Returns a Constraint where (self - other) == 0. Note: This does NOT return bool, it creates a Constraint object.

__ge__(other: ToFunction) → Constraint

Create a greater-than-or-equal constraint: self >= other → Constraint with LessThanOrEqualToZero

Returns a Constraint where (other - self) <= 0.

__iadd__(rhs: ToFunction) → Function
__le__(other: ToFunction) → Constraint

Create a less-than-or-equal constraint: self <= other → Constraint with LessThanOrEqualToZero

Returns a Constraint where (self - other) <= 0.

__mul__(rhs: ToFunction) → Function

Multiplication

__neg__() → Function

Negation operator

__new__(inner: ToFunction) → Function

Create a Function from various types.

Accepts:

  • int or float: creates a constant function

  • DecisionVariable: creates a linear function with single term

  • Parameter: creates a linear function with single term

  • Linear: creates a linear function

  • Quadratic: creates a quadratic function

  • Polynomial: creates a polynomial function

  • Function: returns a copy

__radd__(lhs: ToFunction) → Function

Reverse addition (lhs + self)

__repr__() → str
__rmul__(lhs: ToFunction) → Function

Reverse multiplication (lhs * self)

__rsub__(lhs: ToFunction) → Function

Reverse subtraction (lhs - self)

__sub__(rhs: ToFunction) → Function

Subtraction

add_assign(rhs: ToFunction) → None
add_linear(linear: Linear) → Function
add_polynomial(polynomial: Polynomial) → Function
add_quadratic(quadratic: Quadratic) → Function
add_scalar(scalar: float) → Function
almost_equal(other: ToFunction, atol: float = 1e-06) → bool
as_linear() → Optional[Linear]

Try to convert this function to a linear function.

Returns Some(Linear) if the function can be represented as linear, None otherwise. This is useful for checking if a function is suitable for linear programming solvers.

as_quadratic() → Optional[Quadratic]

Try to convert this function to a quadratic function.

Returns Some(Quadratic) if the function can be represented as quadratic, None otherwise.

content_factor() → float
degree() → int

Get the degree of this function.

Returns the highest degree of any term in the function. Zero function has degree 0, constant function has degree 0, linear function has degree 1, quadratic function has degree 2, etc.

evaluate(state: ToState, atol: Optional[float] = None) → float
from_bytes(bytes: bytes) → Function
from_linear(linear: Linear) → Function
from_polynomial(polynomial: Polynomial) → Function
from_quadratic(quadratic: Quadratic) → Function
from_scalar(scalar: float) → Function
mul_linear(linear: Linear) → Function
mul_polynomial(polynomial: Polynomial) → Function
mul_quadratic(quadratic: Quadratic) → Function
mul_scalar(scalar: float) → Function
num_terms() → int

Get the number of terms in this function.

Zero function has 0 terms, constant function has 1 term, and polynomial functions have the number of non-zero coefficient terms.

partial_evaluate(state: ToState, atol: Optional[float] = None) → Function
random(rng: Rng, num_terms: int = 5, max_degree: int = 3, max_id: int = 10) → Function
reduce_binary_power(binary_ids: set[int]) → bool

Reduce binary powers in the function.

For binary variables, \(x^n = x\) for any \(n \geq 1\), so we can reduce higher powers to linear terms.

Args:

  • binary_ids: Set of binary variable IDs to reduce powers for

Returns: True if any reduction was performed, False otherwise

required_ids() → set[int]
to_bytes() → bytes
property constant_term: float

Read-only property.

Get the constant term of the function.

Returns the constant term. Returns 0.0 if function has no constant term. Works for all polynomial functions by filtering the degree-0 term.

property linear_terms: dict[int, float]

Read-only property.

Get linear terms as a dictionary mapping variable id to coefficient.

Returns dictionary mapping variable IDs to their linear coefficients. Returns empty dict if function has no linear terms. Works for all polynomial functions by filtering only degree-1 terms.

property quadratic_terms: dict[tuple[int, int], float]

Read-only property.

Get quadratic terms as a dictionary mapping (row, col) to coefficient.

Returns dictionary mapping variable ID pairs to their quadratic coefficients. Returns empty dict if function has no quadratic terms. Works for all polynomial functions by filtering only degree-2 terms.

property terms: dict

Read-only property.

property type_name: str

Read-only property.