C++ Reference: class LinearExpr

This documentation is automatically generated.

A dedicated container for linear expressions.

This class helps building and manipulating linear expressions. With the use of implicit constructors, it can accept integer values, Boolean and Integer variables. Note that Not(x) will be silently transformed into 1 - x when added to the linear expression.

Furthermore, static methods allows sums and scalar products, with or without an additional constant.

Usage: CpModelBuilder cp_model; IntVar x = model.NewIntVar(0, 10, "x"); IntVar y = model.NewIntVar(0, 10, "y"); BoolVar b = model.NewBoolVar().WithName("b"); BoolVar c = model.NewBoolVar().WithName("c"); LinearExpr e1(x); // e1 = x. LinearExpr e2 = LinearExpr::Sum({x, y}).AddConstant(5); // e2 = x + y + 5; LinearExpr e3 = LinearExpr::ScalProd({x, y}, {2, -1}); // e3 = 2 * x - y. LinearExpr e4(b); // e4 = b. LinearExpr e5(b.Not()); // e5 = 1 - b. // If passing a std::vector<BoolVar>, a specialized method must be called. std::vector<BoolVar> bools = {b, Not(c)}; LinearExpr e6 = LinearExpr::BooleanSum(bools); // e6 = b + 1 - c; // e7 = -3 * b + 1 - c; LinearExpr e7 = LinearExpr::BooleanScalProd(bools, {-3, 1}); This can be used implicitly in some of the CpModelBuilder methods. cp_model.AddGreaterThan(x, 5); // x > 5 cp_model.AddEquality(x, LinearExpr(y).AddConstant(5)); // x == y + 5

Method
`AddConstant`	Return type: `LinearExpr&` Arguments: `int64 value` Adds a constant value to the linear expression.
`AddTerm`	Return type: `void` Arguments: `IntVar var, int64 coeff` Adds a term (var * coeff) to the linear expression.
`AddVar`	Return type: `void` Arguments: `IntVar var` Adds a single integer variable to the linear expression.
`BooleanScalProd`	Return type: `static LinearExpr` Arguments: `absl::Span<const BoolVar> vars, absl::Span<const int64> coeffs` Constructs the scalar product of Booleans and coefficients.
`BooleanSum`	Return type: `static LinearExpr` Arguments: `absl::Span<const BoolVar> vars` Constructs the sum of a list of Booleans.
`coefficients`	Return type: `const std::vector<int64>&` Returns the vector of coefficients.
`constant`	Return type: `int64` Returns the constant term.
`LinearExpr`
`LinearExpr`	Arguments: `BoolVar var` Constructs a linear expression from a Boolean variable. It deals with logical negation correctly.
`LinearExpr`	Arguments: `IntVar var` Constructs a linear expression from an integer variable.
`LinearExpr`	Arguments: `int64 constant` Constructs a constant linear expression.
`ScalProd`	Return type: `static LinearExpr` Arguments: `absl::Span<const IntVar> vars, absl::Span<const int64> coeffs` Constructs the scalar product of variables and coefficients.
`Sum`	Return type: `static LinearExpr` Arguments: `absl::Span<const IntVar> vars` Constructs the sum of a list of variables.
`Term`	Return type: `static LinearExpr` Arguments: `IntVar var, int64 coefficient` Construncts var * coefficient.
`variables`	Return type: `const std::vector<IntVar>&` Returns the vector of variables.