laddu-compile 0.21.2

Amplitude analysis tools for Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149

use laddu_expr::{ExprGraph, ExprGraphRebuilder, ExprId};

use crate::CompileResult;

pub(crate) fn mark_reachable(
    graph: &ExprGraph,
    roots: impl IntoIterator<Item = ExprId>,
    required: &mut [bool],
) {
    debug_assert_eq!(required.len(), graph.nodes().len());
    for id in graph.reachable_post_order(roots) {
        required[id.index()] = true;
    }
}

pub(crate) fn compact_to_root(graph: &ExprGraph, root: ExprId) -> CompileResult<ExprGraph> {
    let order = graph.reachable_post_order([root]);
    let mut rebuild = ExprGraphRebuilder::with_capacity(order.len());
    for old_id in order {
        let node = graph
            .node(old_id)
            .expect("validated graph traversal only returns valid nodes")
            .map_children(|child| {
                rebuild
                    .remapped(&child)
                    .expect("post-order traversal emits children before parents")
            });
        let metadata = graph
            .metadata(old_id)
            .expect("validated graph metadata is aligned with its nodes")
            .clone();
        rebuild.emit(old_id, node, metadata);
    }
    let root = rebuild
        .remapped(&root)
        .expect("the compacted graph includes its requested root");
    Ok(rebuild.finish(root)?)
}

#[cfg(test)]
mod tests {
    use laddu_expr::{BinaryOp, ExprMetadata, ExprNode, ExprSourceKind, UnaryOp};

    use super::*;

    fn id(index: usize) -> ExprId {
        ExprId::from_index(index)
    }

    #[test]
    fn reachability_handles_empty_and_multiple_root_sets() {
        let graph = ExprGraph::from_parts(
            id(3),
            vec![
                ExprNode::RealConst(1.0),
                ExprNode::RealConst(2.0),
                ExprNode::Unary {
                    op: UnaryOp::Neg,
                    input: id(0),
                },
                ExprNode::Binary {
                    op: BinaryOp::Add,
                    lhs: id(2),
                    rhs: id(1),
                },
            ],
            vec![ExprMetadata::new(ExprSourceKind::Const); 4],
        )
        .unwrap();
        let mut required = vec![false; graph.nodes().len()];
        mark_reachable(&graph, [], &mut required);
        assert_eq!(required, [false; 4]);

        mark_reachable(&graph, [id(1), id(2)], &mut required);
        assert_eq!(required, [true, true, true, false]);
    }

    #[test]
    fn compaction_preserves_shared_children_order_and_metadata() {
        let metadata = [
            ExprMetadata::new(ExprSourceKind::Const),
            ExprMetadata::new(ExprSourceKind::Event),
            ExprMetadata::new(ExprSourceKind::Unary),
            ExprMetadata::new(ExprSourceKind::Binary),
        ];
        let graph = ExprGraph::from_parts(
            id(3),
            vec![
                ExprNode::RealConst(99.0),
                ExprNode::RealConst(2.0),
                ExprNode::Unary {
                    op: UnaryOp::Neg,
                    input: id(1),
                },
                ExprNode::Binary {
                    op: BinaryOp::Add,
                    lhs: id(2),
                    rhs: id(1),
                },
            ],
            metadata.to_vec(),
        )
        .unwrap();

        let compacted = compact_to_root(&graph, graph.root()).unwrap();
        assert_eq!(compacted.nodes().len(), 3);
        assert_eq!(
            compacted
                .node(compacted.root())
                .unwrap()
                .children()
                .collect::<Vec<_>>(),
            [id(1), id(0)]
        );
        assert_eq!(
            (0..3)
                .map(|index| compacted.metadata(id(index)).unwrap().source())
                .collect::<Vec<_>>(),
            [
                ExprSourceKind::Event,
                ExprSourceKind::Unary,
                ExprSourceKind::Binary,
            ]
        );
    }

    #[test]
    fn compaction_is_iterative_for_deep_graphs() {
        const DEPTH: usize = 2_048;
        let mut nodes = Vec::with_capacity(DEPTH + 2);
        nodes.push(ExprNode::RealConst(0.0));
        nodes.push(ExprNode::RealConst(1.0));
        for index in 2..=DEPTH + 1 {
            nodes.push(ExprNode::Unary {
                op: UnaryOp::Neg,
                input: id(index - 1),
            });
        }
        let graph = ExprGraph::from_parts(
            id(DEPTH + 1),
            nodes,
            vec![ExprMetadata::new(ExprSourceKind::Unary); DEPTH + 2],
        )
        .unwrap();

        let compacted = compact_to_root(&graph, graph.root()).unwrap();
        assert_eq!(compacted.nodes().len(), DEPTH + 1);
    }
}