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refactor: start cleaning up SiblingSubgraph convexity checking #2956

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Merged
acl-cqc merged 4 commits into from
Mar 17, 2026
Merged

refactor: start cleaning up SiblingSubgraph convexity checking #2956

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d457622
Drop unused From instance
acl-cqc Mar 17, 2026
eb88d6d
Derive Clone for ConvexChecker rather than manually implement
acl-cqc Mar 17, 2026
61f2e44
Clarify some types are actually fixed as TopoConvexChecker
acl-cqc Mar 17, 2026
bc6cf8c
Abandon OnceCell initialization
acl-cqc Mar 17, 2026
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112 changes: 36 additions & 76 deletions hugr-core/src/hugr/views/sibling_subgraph.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@
//! hierarchy, i.e. within a sibling graph. Convex subgraph are always
//! induced subgraphs, i.e. they are defined by a subset of the sibling nodes.

use std::cell::OnceCell;
use std::collections::HashSet;
use std::mem;

Expand Down Expand Up @@ -228,7 +227,7 @@ impl<N: HugrNode> SiblingSubgraph<N> {

/// Create a new convex sibling subgraph from input and output boundaries.
///
/// Provide a [`ConvexChecker`] instance to avoid constructing one for
/// Provide a [`TopoConvexChecker`] instance to avoid constructing one for
/// faster convexity check. If you do not have one, use
/// [`SiblingSubgraph::try_new`].
///
Expand Down Expand Up @@ -296,7 +295,7 @@ impl<N: HugrNode> SiblingSubgraph<N> {

/// Create a subgraph from a set of nodes.
///
/// Provide a [`ConvexChecker`] instance to avoid constructing one for
/// Provide a [`TopoConvexChecker`] instance to avoid constructing one for
/// faster convexity check. If you do not have one, use
/// [`SiblingSubgraph::try_from_nodes`].
///
Expand Down Expand Up @@ -357,7 +356,7 @@ impl<N: HugrNode> SiblingSubgraph<N> {
intervals: &LineIntervals,
line_checker: &LineConvexChecker<impl HugrView<Node = N>>,
) -> Result<Self, InvalidSubgraph<N>> {
if !line_checker.get_checker().is_convex_by_intervals(intervals) {
if !line_checker.checker.is_convex_by_intervals(intervals) {
return Err(InvalidSubgraph::NotConvex);
}

Expand Down Expand Up @@ -494,14 +493,14 @@ impl<N: HugrNode> SiblingSubgraph<N> {
let checker_ref = match mode {
ValidationMode::WithChecker(c) => Some(c),
ValidationMode::CheckConvexity => {
checker = ConvexChecker::new(hugr, self.get_parent(hugr));
checker = TopoConvexChecker::new(hugr, self.get_parent(hugr));
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@acl-cqc acl-cqc Mar 17, 2026

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ValidationMode::WithChecker specifically contains a TopoConvexChecker so this must match that

Some(&checker)
}
ValidationMode::SkipConvexity => None,
};
if let Some(checker) = checker_ref {
let (subpg, _) = make_pg_subgraph(hugr, &self.inputs, &self.outputs);
if !subpg.is_convex_with_checker(&checker.init_checker().0) {
if !subpg.is_convex_with_checker(&checker.checker) {
return Err(InvalidSubgraph::NotConvex);
}
}
Expand Down Expand Up @@ -983,33 +982,33 @@ pub type LineConvexChecker<'g, Base> =
/// This type is generic over the convexity checker used. If checking convexity
/// for circuit-like graphs, use [`LineConvexChecker`], otherwise use
/// [`TopoConvexChecker`].
#[derive(Clone)]
pub struct ConvexChecker<'g, Base: HugrView, Checker> {
/// The base HUGR to check convexity on.
base: &'g Base,
/// The parent of the region where we are checking convexity.
#[allow(unused)] // Useful for debugging
region_parent: Base::Node,
/// A lazily initialized convexity checker, along with a map from nodes in
/// the region to `Base` nodes.
checker: OnceCell<(Checker, Base::RegionPortgraphNodes)>,
/// A convexity checker initialized for the nodes in that region
checker: Checker,
/// a map from nodes in the region to `Base` nodes.
node_map: Base::RegionPortgraphNodes,
}

impl<'g, Base: HugrView, Checker: Clone> Clone for ConvexChecker<'g, Base, Checker> {
fn clone(&self) -> Self {
Self {
base: self.base,
region_parent: self.region_parent,
checker: self.checker.clone(),
}
}
}

impl<'g, Base: HugrView, Checker> ConvexChecker<'g, Base, Checker> {
impl<'g, Base, Checker> ConvexChecker<'g, Base, Checker>
where
Base: HugrView,
Checker: CreateConvexChecker<CheckerRegion<'g, Base>>,
{
/// Create a new convexity checker.
pub fn new(base: &'g Base, region_parent: Base::Node) -> Self {
let (region, node_map) = base.region_portgraph(region_parent);
let checker = Checker::new_convex_checker(region);
Self {
base,
region_parent,
checker: OnceCell::new(),
checker,
node_map,
}
}

Expand All @@ -1026,32 +1025,6 @@ impl<'g, Base: HugrView, Checker> ConvexChecker<'g, Base, Checker> {
}
}

impl<'g, Base, Checker> ConvexChecker<'g, Base, Checker>
where
Base: HugrView,
Checker: CreateConvexChecker<CheckerRegion<'g, Base>>,
{
/// Returns the portgraph convexity checker, initializing it if necessary.
fn init_checker(&self) -> &(Checker, Base::RegionPortgraphNodes) {
self.checker.get_or_init(|| {
let (region, node_map) = self.base.region_portgraph(self.region_parent);
let checker = Checker::new_convex_checker(region);
(checker, node_map)
})
}

/// Returns the node map from the region to the base HUGR.
#[expect(dead_code)]
fn get_node_map(&self) -> &Base::RegionPortgraphNodes {
&self.init_checker().1
}

/// Returns the portgraph convexity checker, initializing it if necessary.
fn get_checker(&self) -> &Checker {
&self.init_checker().0
}
}

impl<'g, Base, Checker> portgraph::algorithms::ConvexChecker for ConvexChecker<'g, Base, Checker>
where
Base: HugrView,
Expand All @@ -1069,7 +1042,7 @@ where
if nodes.peek().is_none() || nodes.peek().is_none() {
return true;
}
self.get_checker().is_convex(nodes, inputs, outputs)
self.checker.is_convex(nodes, inputs, outputs)
}
}

Expand All @@ -1079,12 +1052,11 @@ impl<'g, Base: HugrView> LineConvexChecker<'g, Base> {
&self,
nodes: impl IntoIterator<Item = Base::Node>,
) -> Option<LineIntervals> {
let (checker, node_map) = self.init_checker();
let nodes = nodes
.into_iter()
.map(|n| node_map.to_portgraph(n))
.map(|n| self.node_map.to_portgraph(n))
.collect_vec();
checker.get_intervals_from_nodes(nodes)
self.checker.get_intervals_from_nodes(nodes)
}

/// Return the line intervals defined by the given boundary ports in the
Expand All @@ -1096,39 +1068,37 @@ impl<'g, Base: HugrView> LineConvexChecker<'g, Base> {
&self,
ports: impl IntoIterator<Item = (Base::Node, Port)>,
) -> Option<LineIntervals> {
let (checker, node_map) = self.init_checker();
let ports = ports
.into_iter()
.map(|(n, p)| {
let node = node_map.to_portgraph(n);
checker
let node = self.node_map.to_portgraph(n);
self.checker
.graph()
.port_index(node, p.pg_offset())
.expect("valid port")
})
.collect_vec();
checker.get_intervals_from_boundary_ports(ports)
self.checker.get_intervals_from_boundary_ports(ports)
}

/// Return the nodes that are within the given line intervals.
pub fn nodes_in_intervals<'a>(
&'a self,
intervals: &'a LineIntervals,
) -> impl Iterator<Item = Base::Node> + 'a {
let (checker, node_map) = self.init_checker();
checker
self.checker
.nodes_in_intervals(intervals)
.map(|pg_node| node_map.from_portgraph(pg_node))
.map(|pg_node| self.node_map.from_portgraph(pg_node))
}

/// Get the lines passing through the given port.
pub fn lines_at_port(&self, node: Base::Node, port: impl Into<Port>) -> &[LineIndex] {
let (checker, node_map) = self.init_checker();
let port = checker
let port = self
.checker
.graph()
.port_index(node_map.to_portgraph(node), port.into().pg_offset())
.port_index(self.node_map.to_portgraph(node), port.into().pg_offset())
.expect("valid port");
checker.lines_at_port(port)
self.checker.lines_at_port(port)
}

/// Extend the given intervals to include the given node.
Expand All @@ -1139,16 +1109,14 @@ impl<'g, Base: HugrView> LineConvexChecker<'g, Base> {
///
/// If `false` is returned, the `intervals` are left unchanged.
pub fn try_extend_intervals(&self, intervals: &mut LineIntervals, node: Base::Node) -> bool {
let (checker, node_map) = self.init_checker();
let node = node_map.to_portgraph(node);
checker.try_extend_intervals(intervals, node)
let node = self.node_map.to_portgraph(node);
self.checker.try_extend_intervals(intervals, node)
}

/// Get the position of a node on its lines.
pub fn get_position(&self, node: Base::Node) -> Position {
let (checker, node_map) = self.init_checker();
let node = node_map.to_portgraph(node);
checker.get_position(node)
let node = self.node_map.to_portgraph(node);
self.checker.get_position(node)
}
}

Expand Down Expand Up @@ -1379,14 +1347,6 @@ fn is_non_value_edge<H: HugrView>(hugr: &H, node: H::Node, port: Port) -> bool {
is_other || is_static
}

impl<'a, 'c, G: HugrView, Checker: Clone> From<&'a ConvexChecker<'c, G, Checker>>
for std::borrow::Cow<'a, ConvexChecker<'c, G, Checker>>
{
fn from(value: &'a ConvexChecker<'c, G, Checker>) -> Self {
Self::Borrowed(value)
}
}

/// Errors that can occur while constructing a [`SimpleReplacement`].
#[derive(Debug, Clone, PartialEq, Error)]
#[non_exhaustive]
Expand Down
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