Constraint

cplex_dynamic

Struct Constraint 

Source 
pub struct Constraint { /* private fields */ }
Expand description

export all public structs and enums A Constraint (row) object for a Problem.

The recommended way to build these is with the con! macro.

#[macro_use]
extern crate rplex;

use rplex::{Env, Problem, Variable};

fn main() {
    let env = Env::new().unwrap();
    let mut prob = Problem::new(&env, "dummy").unwrap();
    let x = prob.add_variable(var!("x" -> 4.0 as Binary)).unwrap();
    let y = prob.add_variable(var!(0.0 <= "y" <= 100.0  -> 3.0 as Integer)).unwrap();
    let z = prob.add_variable(var!(0.0 <= "z" <= 4.5 -> 2.0)).unwrap();
    prob.add_constraint(con!("dummy": 20.0 = 1.0 x + 2.0 y + 3.0 z)).unwrap();
    prob.add_constraint(con!("dummy2": 1.0 <= (-1.0) x + 1.0 y)).unwrap();
}

However, constraints can also be constructed manually from WeightedVariables. This can be useful if your constraints don’t quite fit the grammar allowed by the con! macro. You can create part of the constraint using con!, then augment it with add_wvar to obtain the constraint you need.The following example is identical to the above.

#[macro_use]
extern crate rplex;

use rplex::{Env, Problem, Constraint, ConstraintType, WeightedVariable};

fn main() {
    let env = Env::new().unwrap();
    let mut prob = Problem::new(&env, "dummy").unwrap();
    let x = prob.add_variable(var!("x" -> 4.0 as Binary)).unwrap();
    let y = prob.add_variable(var!(0.0 <= "y" <= 100.0  -> 3.0 as Integer)).unwrap();
    let z = prob.add_variable(var!(0.0 <= "z" <= 4.5 -> 2.0)).unwrap();
    let mut dummy = Constraint::new(ConstraintType::Eq, 20.0, "dummy");
    dummy.add_wvar(WeightedVariable::new_idx(x, 1.0));
    dummy.add_wvar(WeightedVariable::new_idx(y, 2.0));
    dummy.add_wvar(WeightedVariable::new_idx(z, 3.0));
    prob.add_constraint(dummy).unwrap();
    let mut dummy2 = Constraint::new(ConstraintType::GreaterThanEq, 1.0, "dummy2");
    dummy2.add_wvar(WeightedVariable::new_idx(x, -1.0));
    dummy2.add_wvar(WeightedVariable::new_idx(y, 1.0));
    prob.add_constraint(dummy2).unwrap();
}

Implementations§

Source§

impl Constraint

Source

pub fn new<S, F>(ty: ConstraintType, rhs: F, name: S) -> Constraint
where S: Into<String>, F: Into<f64>,

Examples found in repository?
examples/qcp.rs (line 42)
7fn main() {
8    let num_n = 6_usize;
9    let dim = 3_usize;
10    let env = Env::new().unwrap();
11
12    // starting moment
13    let t1 = std::time::Instant::now();
14    // populate it with a problem
15    let mut prob = Problem::new(&env, "miqpex1").unwrap();
16
17    for i in 0..dim * num_n * 4 {
18        let name = format!("x{:02}", i);
19        let _x = prob
20            .add_variable(Variable::new(
21                VariableType::Continuous,
22                0.0,
23                -100.0,
24                100.0,
25                name,
26            ))
27            .unwrap();
28    }
29    let p_s = [1.0, 0.0, -1.0];
30    let v_s = [0.0, 0.0, 0.0];
31    let a_s = [0.0, 0.0, 0.0];
32    let p_g = [8.0, 18.0, 5.0];
33    let v_g = [0.0, 0.0, 5.0];
34    let a_g = [0.0, 0.0, 0.0];
35
36    let dt: f64 = 1.0;
37    let mut num_con = 0;
38
39    // init constraint
40    for k in 0_usize..3 {
41        // position
42        let mut dummy = Constraint::new(ConstraintType::Eq, p_s[k], format!("dummy{}", num_con));
43        dummy.add_wvar(WeightedVariable::new_idx(9 + k, 1.0));
44        prob.add_constraint(dummy).unwrap();
45        num_con += 1;
46
47        // velocity
48        let mut dummy = Constraint::new(ConstraintType::Eq, v_s[k], format!("dummy{}", num_con));
49        dummy.add_wvar(WeightedVariable::new_idx(6 + k, 1.0));
50        prob.add_constraint(dummy).unwrap();
51        num_con += 1;
52
53        //accelerate
54        let mut dummy = Constraint::new(ConstraintType::Eq, a_s[k], format!("dummy{}", num_con));
55        dummy.add_wvar(WeightedVariable::new_idx(3 + k, 2.0));
56        prob.add_constraint(dummy).unwrap();
57        num_con += 1;
58    }
59
60    // final constraint
61    let base = (num_n - 1) * 12;
62    for k in 0_usize..3 {
63        // position
64        let mut dummy = Constraint::new(ConstraintType::Eq, p_g[k], format!("dummy{}", num_con));
65        dummy.add_wvar(WeightedVariable::new_idx(base + k, dt.powi(3)));
66        dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, dt.powi(2)));
67        dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, dt));
68        dummy.add_wvar(WeightedVariable::new_idx(base + 9 + k, 1.0));
69        prob.add_constraint(dummy).unwrap();
70        num_con += 1;
71
72        // velocity
73        let mut dummy = Constraint::new(ConstraintType::Eq, v_g[k], format!("dummy{}", num_con));
74        dummy.add_wvar(WeightedVariable::new_idx(base + k, 3.0 * dt.powi(2)));
75        dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0 * dt));
76        dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, 1.0));
77        prob.add_constraint(dummy).unwrap();
78        num_con += 1;
79
80        //accelerate
81        let mut dummy = Constraint::new(ConstraintType::Eq, a_g[k], format!("dummy{}", num_con));
82        dummy.add_wvar(WeightedVariable::new_idx(base + k, 6.0 * dt));
83        dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0));
84        prob.add_constraint(dummy).unwrap();
85        num_con += 1;
86    }
87
88    // continuity
89
90    for i in 0..num_n - 1 {
91        let base = i * 12;
92        for k in 0_usize..dim {
93            // position
94            let mut dummy = Constraint::new(ConstraintType::Eq, 0.0, format!("dummy{}", num_con));
95            dummy.add_wvar(WeightedVariable::new_idx(base + k, dt.powi(3)));
96            dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, dt.powi(2)));
97            dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, dt));
98            dummy.add_wvar(WeightedVariable::new_idx(base + 9 + k, 1.0));
99            dummy.add_wvar(WeightedVariable::new_idx(base + 12 + 9 + k, -1.0));
100            prob.add_constraint(dummy).unwrap();
101            num_con += 1;
102
103            // velocity
104            let mut dummy = Constraint::new(ConstraintType::Eq, 0.0, format!("dummy{}", num_con));
105            dummy.add_wvar(WeightedVariable::new_idx(base + k, 3.0 * dt.powi(2)));
106            dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0 * dt));
107            dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, 1.0));
108            dummy.add_wvar(WeightedVariable::new_idx(base + 12 + 6 + k, -1.0));
109            prob.add_constraint(dummy).unwrap();
110            num_con += 1;
111
112            //accelerate
113            let mut dummy =
114                Constraint::new(ConstraintType::Eq, a_g[k], format!("dummy{}", num_con));
115            dummy.add_wvar(WeightedVariable::new_idx(base + k, 6.0 * dt));
116            dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0));
117            dummy.add_wvar(WeightedVariable::new_idx(base + 12 + 3 + k, -2.0));
118            prob.add_constraint(dummy).unwrap();
119            num_con += 1;
120        }
121    }
122
123    // maximize the objective
124    let mut qp_vars: Vec<usize> = Vec::new();
125    let dummy = Constraint::new(ConstraintType::Eq, 0.0, "obj");
126    for i in 0..num_n {
127        let base = i * 12;
128        for k in 0..dim {
129            qp_vars.push(base + k);
130            // dummy.add_wvar(WeightedVariable::new_idx(base + k, 0.0));
131        }
132    }
133    prob.set_qp_objective(ObjectiveType::Minimize, dummy, qp_vars.clone(), dt / 36.0)
134        .unwrap();
135
136    // solve the problem
137    let sol = prob.solve(ProblemType::MixedInteger).unwrap();
138
139    let t2 = std::time::Instant::now();
140
141    println!("time cost {:?}", t2 - t1);
142
143    println!("{:.4?}", sol);
144    let sol_vars = sol.variables;
145    let mut f = 0.0_f64;
146    for idx in qp_vars.into_iter() {
147        let value = sol_vars[idx];
148        if let VariableValue::Continuous(v) = value {
149            f += v.powi(2);
150        }
151    }
152    f = f * dt / 36.0 / 2.0;
153    println!("f = {}", f);
154}
Source

pub fn add_wvar(&mut self, wvar: WeightedVariable)

Move a WeightedVariable into the Constraint.

Examples found in repository?
examples/qcp.rs (line 43)
7fn main() {
8    let num_n = 6_usize;
9    let dim = 3_usize;
10    let env = Env::new().unwrap();
11
12    // starting moment
13    let t1 = std::time::Instant::now();
14    // populate it with a problem
15    let mut prob = Problem::new(&env, "miqpex1").unwrap();
16
17    for i in 0..dim * num_n * 4 {
18        let name = format!("x{:02}", i);
19        let _x = prob
20            .add_variable(Variable::new(
21                VariableType::Continuous,
22                0.0,
23                -100.0,
24                100.0,
25                name,
26            ))
27            .unwrap();
28    }
29    let p_s = [1.0, 0.0, -1.0];
30    let v_s = [0.0, 0.0, 0.0];
31    let a_s = [0.0, 0.0, 0.0];
32    let p_g = [8.0, 18.0, 5.0];
33    let v_g = [0.0, 0.0, 5.0];
34    let a_g = [0.0, 0.0, 0.0];
35
36    let dt: f64 = 1.0;
37    let mut num_con = 0;
38
39    // init constraint
40    for k in 0_usize..3 {
41        // position
42        let mut dummy = Constraint::new(ConstraintType::Eq, p_s[k], format!("dummy{}", num_con));
43        dummy.add_wvar(WeightedVariable::new_idx(9 + k, 1.0));
44        prob.add_constraint(dummy).unwrap();
45        num_con += 1;
46
47        // velocity
48        let mut dummy = Constraint::new(ConstraintType::Eq, v_s[k], format!("dummy{}", num_con));
49        dummy.add_wvar(WeightedVariable::new_idx(6 + k, 1.0));
50        prob.add_constraint(dummy).unwrap();
51        num_con += 1;
52
53        //accelerate
54        let mut dummy = Constraint::new(ConstraintType::Eq, a_s[k], format!("dummy{}", num_con));
55        dummy.add_wvar(WeightedVariable::new_idx(3 + k, 2.0));
56        prob.add_constraint(dummy).unwrap();
57        num_con += 1;
58    }
59
60    // final constraint
61    let base = (num_n - 1) * 12;
62    for k in 0_usize..3 {
63        // position
64        let mut dummy = Constraint::new(ConstraintType::Eq, p_g[k], format!("dummy{}", num_con));
65        dummy.add_wvar(WeightedVariable::new_idx(base + k, dt.powi(3)));
66        dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, dt.powi(2)));
67        dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, dt));
68        dummy.add_wvar(WeightedVariable::new_idx(base + 9 + k, 1.0));
69        prob.add_constraint(dummy).unwrap();
70        num_con += 1;
71
72        // velocity
73        let mut dummy = Constraint::new(ConstraintType::Eq, v_g[k], format!("dummy{}", num_con));
74        dummy.add_wvar(WeightedVariable::new_idx(base + k, 3.0 * dt.powi(2)));
75        dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0 * dt));
76        dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, 1.0));
77        prob.add_constraint(dummy).unwrap();
78        num_con += 1;
79
80        //accelerate
81        let mut dummy = Constraint::new(ConstraintType::Eq, a_g[k], format!("dummy{}", num_con));
82        dummy.add_wvar(WeightedVariable::new_idx(base + k, 6.0 * dt));
83        dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0));
84        prob.add_constraint(dummy).unwrap();
85        num_con += 1;
86    }
87
88    // continuity
89
90    for i in 0..num_n - 1 {
91        let base = i * 12;
92        for k in 0_usize..dim {
93            // position
94            let mut dummy = Constraint::new(ConstraintType::Eq, 0.0, format!("dummy{}", num_con));
95            dummy.add_wvar(WeightedVariable::new_idx(base + k, dt.powi(3)));
96            dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, dt.powi(2)));
97            dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, dt));
98            dummy.add_wvar(WeightedVariable::new_idx(base + 9 + k, 1.0));
99            dummy.add_wvar(WeightedVariable::new_idx(base + 12 + 9 + k, -1.0));
100            prob.add_constraint(dummy).unwrap();
101            num_con += 1;
102
103            // velocity
104            let mut dummy = Constraint::new(ConstraintType::Eq, 0.0, format!("dummy{}", num_con));
105            dummy.add_wvar(WeightedVariable::new_idx(base + k, 3.0 * dt.powi(2)));
106            dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0 * dt));
107            dummy.add_wvar(WeightedVariable::new_idx(base + 6 + k, 1.0));
108            dummy.add_wvar(WeightedVariable::new_idx(base + 12 + 6 + k, -1.0));
109            prob.add_constraint(dummy).unwrap();
110            num_con += 1;
111
112            //accelerate
113            let mut dummy =
114                Constraint::new(ConstraintType::Eq, a_g[k], format!("dummy{}", num_con));
115            dummy.add_wvar(WeightedVariable::new_idx(base + k, 6.0 * dt));
116            dummy.add_wvar(WeightedVariable::new_idx(base + 3 + k, 2.0));
117            dummy.add_wvar(WeightedVariable::new_idx(base + 12 + 3 + k, -2.0));
118            prob.add_constraint(dummy).unwrap();
119            num_con += 1;
120        }
121    }
122
123    // maximize the objective
124    let mut qp_vars: Vec<usize> = Vec::new();
125    let dummy = Constraint::new(ConstraintType::Eq, 0.0, "obj");
126    for i in 0..num_n {
127        let base = i * 12;
128        for k in 0..dim {
129            qp_vars.push(base + k);
130            // dummy.add_wvar(WeightedVariable::new_idx(base + k, 0.0));
131        }
132    }
133    prob.set_qp_objective(ObjectiveType::Minimize, dummy, qp_vars.clone(), dt / 36.0)
134        .unwrap();
135
136    // solve the problem
137    let sol = prob.solve(ProblemType::MixedInteger).unwrap();
138
139    let t2 = std::time::Instant::now();
140
141    println!("time cost {:?}", t2 - t1);
142
143    println!("{:.4?}", sol);
144    let sol_vars = sol.variables;
145    let mut f = 0.0_f64;
146    for idx in qp_vars.into_iter() {
147        let value = sol_vars[idx];
148        if let VariableValue::Continuous(v) = value {
149            f += v.powi(2);
150        }
151    }
152    f = f * dt / 36.0 / 2.0;
153    println!("f = {}", f);
154}

Trait Implementations§

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impl Clone for Constraint

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fn clone(&self) -> Constraint

Returns a duplicate of the value. Read more
1.0.0 · Source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Constraint

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

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fn type_id(&self) -> TypeId

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impl<T> Borrow<T> for T
where T: ?Sized,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
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fn from(t: T) -> T

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Calls U::from(self).

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