Solve a linear or mixed-integer program using SCIP

One-shot interface to the SCIP solver. Formulates and solves: $$\min_{x} \; obj' x$$ subject to constraint rows defined by A, b, sense, with variable types vtype and bounds lb, ub.

Usage

scip_solve(obj, A, b, sense, vtype = "C", lb = 0, ub = Inf, control = list())

Arguments

obj

Numeric vector of length n; objective coefficients.

A

Constraint matrix (m x n). Can be a dense matrix, dgCMatrix, or simple_triplet_matrix.

b

Numeric vector of length m; constraint right-hand side.

sense

Character vector of length m; constraint sense. Each element must be "<=", ">=", or "==".

vtype

Character; variable types. Either a single value applied to all variables, or a vector of length n. Values: "C" (continuous), "B" (binary), "I" (integer). Default "C".

lb

Numeric; lower bounds for variables. Single value or vector of length n. Default 0.

ub

Numeric; upper bounds for variables. Single value or vector of length n. Default Inf.

control

A list of solver parameters, typically from scip_control.

Value

A named list with components:

status

Character; solver status (e.g., "optimal", "infeasible", "unbounded").

objval

Numeric; optimal objective value (or NA if no solution).

x

Numeric vector; primal solution (or NULL if no solution).

sol_count

Integer; number of solutions found.

gap

Numeric; relative optimality gap.

info

List with additional solver information (solve_time, iterations, nodes).