numopt/model/
variable.rs

1//! Optimization variables.
2
3use std::fmt;
4use std::rc::Rc;
5
6use super::node::Node;
7use super::node_base::NodeBase;
8use super::constant::ConstantScalar;
9
10/// Optimization variable kind.
11pub enum VariableKind {
12    VarContinuous,
13    VarInteger,
14}
15
16/// Scalar optimization variable.
17pub struct VariableScalar {
18    name: String,
19    kind: VariableKind,
20}
21
22impl VariableScalar {
23
24    /// Determines whether optimization variable is a continuous variable.
25    pub fn is_continuous(&self) -> bool {
26        match self.kind {
27            VariableKind::VarContinuous => true,
28            _ => false,
29        }
30    }
31
32    /// Determines whether optimization variable is an integer variable.
33    pub fn is_integer(&self) -> bool {
34        match self.kind {
35            VariableKind::VarInteger => true,
36            _ => false,
37        }
38    }
39
40    /// Gets optimization variable name.
41    pub fn name(&self) -> &str { self.name.as_ref() }
42
43    /// Creates a new optimization variable expression node.
44    pub fn new(name: &str, kind: VariableKind) -> Node {
45        Node::VariableScalar(Rc::new(
46            Self {
47                name: name.to_string(),
48                kind: kind,
49            }
50        ))
51    }
52
53    /// Creates a new continuous optimization variable expression node.
54    pub fn new_continuous(name: &str) -> Node {
55        VariableScalar::new(name, VariableKind::VarContinuous)
56    }
57
58    /// Creates a new integer optimization variable expression node.
59    pub fn new_integer(name: &str) -> Node {
60        VariableScalar::new(name, VariableKind::VarInteger)
61    }
62}
63
64impl NodeBase for VariableScalar {
65
66    fn partial(&self, arg: &Node) -> Node { 
67        match arg {
68            Node::VariableScalar(x) => {
69                if self as *const VariableScalar == x.as_ref() {
70                    ConstantScalar::new(1.)       
71                }
72                else {
73                    ConstantScalar::new(0.)       
74                }
75            }
76            _ => ConstantScalar::new(0.)  
77        }
78    }
79}
80
81impl<'a> fmt::Display for VariableScalar {
82    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
83        write!(f, "{}", self.name)
84    }
85}
86
87#[cfg(test)]
88mod tests {
89
90    use crate::model::node::Node;
91    use crate::model::node_base::NodeBase;
92    use crate::model::node_std::NodeStd;
93    use crate::model::node_diff::NodeDiff;
94    use crate::model::variable::VariableScalar;
95
96    #[test]
97    fn var_construction() {
98
99        let x = VariableScalar::new_continuous("x");
100        assert_eq!(x.name(), "x");
101        match x {
102            Node::VariableScalar(xx) => {
103                assert!(xx.is_continuous());
104                assert!(!xx.is_integer());
105            },
106            _ => panic!("construction failed"),
107        }
108
109        let y = VariableScalar::new_integer("y");
110        assert_eq!(y.name(), "y");
111        match y {
112            Node::VariableScalar(yy) => {
113                assert!(yy.is_integer());
114                assert!(!yy.is_continuous());
115            },
116            _ => panic!("construction failed"),
117        }
118    }
119
120    #[test]
121    fn var_partial() {
122
123        let x = VariableScalar::new_continuous("x");
124        let y = VariableScalar::new_continuous("y");
125
126        let z1 = x.partial(&x);
127        assert!(z1.is_constant_with_value(1.));
128
129        let z2 = x.partial(&y);
130        assert!(z2.is_constant_with_value(0.));
131    }
132
133    #[test]
134    fn var_derivative() {
135
136        let x = VariableScalar::new_continuous("x");
137        let y = VariableScalar::new_continuous("y");
138
139        let z1 = x.derivative(&y);
140        assert!(z1.is_constant_with_value(0.));
141
142        let z2 = x.derivative(&x);
143        assert!(z2.is_constant_with_value(1.));
144    }
145
146    #[test]
147    fn var_std_properties() {
148
149        let x = VariableScalar::new_integer("x");
150        let p = x.std_properties();
151        assert!(p.affine);
152        assert_eq!(p.b, 0.);
153        assert_eq!(p.a.len(), 1);
154        assert_eq!(*p.a.get(&x).unwrap(), 1.);
155    }
156}
numopt/model/variable.rs

numopt/model/
variable.rs
