opensrdk_symbolic_computation/expression/operators/
neg.rs

1use crate::{BracketsLevel, Expression, ExpressionArray};
2use std::{collections::HashMap, ops::Neg};
3
4impl Neg for Expression {
5    type Output = Self;
6
7    fn neg(self) -> Self::Output {
8        if let Expression::PartialVariable(v) = &self {
9            return Expression::PartialVariable(ExpressionArray::from_factory(
10                v.sizes().to_vec(),
11                |indices| Expression::Neg(v[indices].clone().into()),
12            ));
13        }
14
15        if let Expression::Constant(mut v) = self {
16            v.elems_mut().into_iter().for_each(|v| *v = -*v);
17            return v.into();
18        }
19        if let Expression::Neg(v) = self {
20            return *v;
21        }
22
23        Expression::Neg(self.into())
24    }
25}
26
27impl Expression {
28    pub(crate) fn diff_neg(v: &Box<Expression>, variable_ids: &[&str]) -> Vec<Expression> {
29        v.differential(variable_ids)
30            .into_iter()
31            .map(|e| -e)
32            .collect()
33    }
34
35    pub(crate) fn tex_code_neg(v: &Box<Expression>, symbols: &HashMap<&str, &str>) -> String {
36        format!("{{-{}}}", v._tex_code(symbols, BracketsLevel::ForOperation))
37    }
38}
39
40#[cfg(test)]
41mod tests {
42    use std::{
43        collections::HashMap,
44        ops::{Add, Neg},
45    };
46
47    use opensrdk_linear_algebra::sparse::SparseTensor;
48
49    use crate::Expression;
50
51    #[test]
52    fn it_works() {
53        let a1 = 5.0f64;
54        let b1 = vec![a1; 8];
55        let mut hash1 = HashMap::new();
56        hash1.insert(vec![3, 2, 1], 2.0);
57        hash1.insert(vec![1usize; 3], 3.0);
58        hash1.insert(vec![4usize; 3], 4.0);
59        hash1.insert(vec![5usize; 3], 2.0);
60        let c1 = SparseTensor::from(vec![6usize; 3], hash1).unwrap();
61
62        let ea1 = Expression::from(a1);
63        let eb1 = Expression::from(b1.clone());
64        let ec1 = Expression::from(c1.clone());
65
66        let ea = ea1.neg();
67        let eb = eb1.neg();
68        let ec = ec1.neg();
69
70        let a = Expression::from(-a1);
71        let b = Expression::from(b1.iter().map(|j| -j).collect::<Vec<f64>>());
72        let c = Expression::from(-c1);
73
74        assert_eq!(ea, a);
75        assert_eq!(eb, b);
76        assert_eq!(ec, c);
77    }
78}
opensrdk_symbolic_computation/expression/operators/neg.rs

opensrdk_symbolic_computation/expression/operators/
neg.rs
