Row

class Row : public idol::impl::Row

Row modeling-old object.

This class is used to represent an optimization model’s row. It is made of a right hand-side and a set of { Var, Constant } pairs representing the coefficient (Constant) of the row in each column (Var). Such pairs are called left hand-side terms.

The whole left hand-side is stored as an Expr<Var, Var> while the whole right hand-side is stored as a Constant.

Example:

auto constraint = model.add_ctr(x + y <= 1.);
const auto& row = model.get_ctr_row(constraint); // Row(x + y, 1.)

Public Functions

Row() = default

inline Row(Expr<Var, Var> &&t_lhs, Expr<Var, Var> &&t_rhs)

Constructor.

Creates a new row with a left hand-side t_lhs and a right hand-side t_rhs.

Parameters:

• t_lhs – The left hand-side.

• t_rhs – The right hand-side.

inline Row(Expr<Var, Var> &&t_lhs, const Expr<Var, Var> &t_rhs)

Constructor.

Creates a new row with a left hand-side t_lhs and a right hand-side t_rhs.

Parameters:

• t_lhs – The left hand-side.

• t_rhs – The right hand-side.

inline Row(const Expr<Var, Var> &t_lhs, Expr<Var, Var> &&t_rhs)

Constructor.

Creates a new row with a left hand-side t_lhs and a right hand-side t_rhs.

Parameters:

• t_lhs – The left hand-side.

• t_rhs – The right hand-side.

inline Row(const Expr<Var, Var> &t_lhs, const Expr<Var, Var> &t_rhs)

Constructor.

Creates a new row with a left hand-side t_lhs and a right hand-side t_rhs.

Parameters:

• t_lhs – The left hand-side.

• t_rhs – The right hand-side.

Row(const Row &t_src) = default

Copy constructor.

Parameters:

t_src – The row to copy.

Row(Row &&t_src) noexcept = default

Move constructor.

Parameters:

t_src – The row to move.

Row &operator=(const Row &t_src) = default

Copy-assignment operator.

Parameters:

t_src – The row to copy.

Returns:

*this

Row &operator=(Row &&t_src) noexcept = default

Move-assignment operator.

Parameters:

t_src – The row to move.

Returns:

*this

Row fix(const Solution::Primal &t_primals) const

Creates a new row in which all Param in each Constant are replaced by their corresponding values in t_primals

Parameters:

t_primals – the primal values for the parameters.

Returns:

the new row.

Row fix(const Solution::Dual &t_duals) const

Creates a new row in which all Param in each Constant are replaced by their corresponding values in t_duals

Parameters:

t_primals – the dual values for the parameters.

Returns:

the new row.

double value(const Solution::Primal &t_primals) const

Returns the value of the row if the value of each variable is taken in t_primals, i.e., the difference between the left and the right hand-side.

If parameters are encountered, an exception is thrown.

Parameters:

t_primals – The primal values.

Returns:

The value of the row.

bool is_violated(const Solution::Primal &t_primals, CtrType t_type, double t_tolerance = Tolerance::Feasibility) const

Returns true if the point stored in t_primals violates the constraint formed by the row and a constraint type t_type with tolerance t_tolerance.

Parameters:

• t_primals – The primal values.

• t_type – The type of the constraint.

• t_tolerance – The tolerance for feasibility.

Returns:

True if the given point violates the row.

inline Constant &rhs()

Returns the right hand-side of the row.

Returns:

The right hand-side of the row.

inline const Constant &rhs() const

Returns the right hand-side of the row.

Returns:

The right hand-side of the row.

inline LinExpr<Var> &linear()

Returns the linear part of the left hand-side of the row.

Returns:

The linear part of the left hand-side of the row.

inline const LinExpr<Var> &linear() const

Returns the linear part of the left hand-side of the row.

Returns:

The linear part of the left hand-side of the row.

inline QuadExpr<Var, Var> &quadratic()

Returns the quadratic part of the left hand-side of the row.

Returns:

The quadratic part of the left hand-side of the row.

inline const QuadExpr<Var, Var> &quadratic() const

Returns the quadratic part of the left hand-side of the row.

Returns:

The quadratic part of the left hand-side of the row.

inline void set_linear(LinExpr<Var> &&t_lin_expr)

Sets the linear part of the left hand-side of the row.

Parameters:

t_lin_expr – The new linear part of the right hand-side.

inline void set_linear(const LinExpr<Var> &t_lin_expr)

Sets the linear part of the left hand-side of the row.

Parameters:

t_lin_expr – The new linear part of the right hand-side.

inline void set_quadratic(QuadExpr<Var, Var> &&t_quad_expr)

Sets the quadratic part of the left hand-side of the row.

Parameters:

t_lin_expr – The new quadratic part of the right hand-side.

inline void set_quadratic(const QuadExpr<Var, Var> &t_quad_expr)

Sets the quadratic part of the left hand-side of the row.

Parameters:

t_lin_expr – The new quadratic part of the right hand-side.

inline void set_rhs(Constant &&t_rhs)

Sets the right hand-side of the row.

Parameters:

t_rhs – The new right hand-side of the row.

inline void set_rhs(const Constant &t_rhs)

Sets the right hand-side of the row.

Parameters:

t_rhs – The new right hand-side of the row.

inline Row &operator+=(const Row &t_rhs)

Adds another row to the row (both the left and right hand-sides are added).

Parameters:

t_rhs – The row to add.

Returns:

*this

inline Row &operator-=(const Row &t_rhs)

Subtracts another row to the row (both the left and right hand-sides are subtracted).

Parameters:

t_rhs – The row to subtarct.

Returns:

*this

inline Row &operator*=(double t_rhs)

Multiplies all the entries of the row by a given factor (both the left and right hand-sides are multiplied).

Parameters:

t_rhs – The factor used for multiplication.

Returns:

*this

inline Row &operator/=(double t_rhs)

double scale_to_integers(unsigned int t_n_significant_digits)

void multiply_with_precision_by_power_of_10(unsigned int t_exponent, unsigned int t_n_significant_digits)

double gcd() const

Public Static Attributes

static const Row EmptyRow

Represents an empty row.