feat(autorouter/permuter): Implement permutation by ratline cut

Not yet used, and can get stuck in an infinite loop, but the cut seems
to work.

crates/planar-incr-embed/src/navmesh/ordered_pair.rs

@@ -9,7 +9,7 @@
     feature = "serde",
     serde(bound(deserialize = "T: serde::Deserialize<'de> + Ord"))
 )]
-pub struct OrderedPair<T>(T, T);
+pub struct OrderedPair<T>(pub T, pub T);
 
 impl<T> core::ops::Index<bool> for OrderedPair<T> {
     type Output = T;

src/autorouter/autoroute.rs

@@ -7,6 +7,8 @@
 
 use std::ops::ControlFlow;
 
+use derive_getters::Getters;
+
 use crate::{
     board::{
         edit::{BoardDataEdit, BoardEdit},
@@ -38,6 +40,7 @@ pub enum AutorouteContinueStatus {
 }
 
 /// Manages the autorouting process across multiple ratlines.
+#[derive(Getters)]
 pub struct AutorouteExecutionStepper {
     /// The ratlines which we are routing.
     ratlines: Vec<RatlineIndex>,

src/autorouter/autorouter.rs

@@ -130,13 +130,7 @@ impl<M: AccessMesadata> Autorouter<M> {
         ratlines: Vec<RatlineIndex>,
     ) -> Result<(), AutorouterError> {
         for ratline in ratlines.iter() {
-            let band = self
-                .ratsnest
-                .graph()
-                .edge_weight(*ratline)
-                .unwrap()
-                .band_termseg
-                .unwrap();
+            let band = ratline.ref_(self).band_termseg();
             self.board
                 .layout_mut()
                 .remove_band(&mut LayoutEdit::new(), band)

src/autorouter/permutator.rs

@@ -10,7 +10,8 @@ use crate::{
     autorouter::{
         autoroute::{AutorouteContinueStatus, AutorouteExecutionStepper},
         invoker::GetDebugOverlayData,
-        permuter::{PermuteRatlines, RatlinesPermuter, SccPermutationsRatlinePermuter},
+        permuter::{PermuteRatlines, RatlinesPermuter},
+        presorter::{PresortRatlines, SccIntersectionsAndLengthPresorter},
         ratline::RatlineIndex,
         Autorouter, AutorouterError, AutorouterOptions,
     },
@@ -33,10 +34,12 @@ impl AutorouteExecutionPermutator {
         ratlines: Vec<RatlineIndex>,
         options: AutorouterOptions,
     ) -> Result<Self, AutorouterError> {
-        let mut permuter = RatlinesPermuter::SccPermutations(SccPermutationsRatlinePermuter::new(
-            autorouter, ratlines, &options,
-        ));
-        let initially_sorted_ratlines = permuter.next_ratlines_permutation(autorouter).unwrap();
+        let presorter = SccIntersectionsAndLengthPresorter::new(autorouter, &ratlines);
+        let initially_sorted_ratlines = presorter.presort_ratlines(autorouter, &ratlines);
+        /*let permuter = RatlinesPermuter::SccPermutations(SccPermutationsRatlinePermuter::new(
+            autorouter, ratlines, presorter, &options,
+        ));*/
+        let permuter = RatlinesPermuter::new(autorouter, ratlines, presorter, &options);
 
         Ok(Self {
             stepper: AutorouteExecutionStepper::new(
@@ -68,7 +71,8 @@ impl<M: AccessMesadata> Step<Autorouter<M>, Option<BoardEdit>, AutorouteContinue
                 }
 
                 loop {
-                    let Some(permutation) = self.permuter.next_ratlines_permutation(autorouter)
+                    let Some(permutation) =
+                        self.permuter.permute_ratlines(autorouter, &self.stepper)
                     else {
                         return Ok(ControlFlow::Break(None));
                     };

src/autorouter/permuter.rs

@@ -2,26 +2,35 @@
 //
 // SPDX-License-Identifier: MIT
 
+use std::iter::Skip;
+
 use enum_dispatch::enum_dispatch;
 use itertools::{Itertools, Permutations};
 use petgraph::graph::NodeIndex;
 use specctra_core::mesadata::AccessMesadata;
 
-use crate::autorouter::{
-    presorter::SccIntersectionsAndLengthPresorter, ratline::RatlineIndex, Autorouter,
-    AutorouterOptions,
+use crate::{
+    autorouter::{
+        autoroute::AutorouteExecutionStepper, presorter::SccIntersectionsAndLengthPresorter,
+        ratline::RatlineIndex, Autorouter, AutorouterOptions,
+    },
+    drawing::graph::MakePrimitive,
+    geometry::{GenericNode, GetLayer},
+    graph::MakeRef,
 };
 
 #[enum_dispatch]
 pub trait PermuteRatlines {
-    fn next_ratlines_permutation(
+    fn permute_ratlines(
         &mut self,
         autorouter: &mut Autorouter<impl AccessMesadata>,
+        stepper: &AutorouteExecutionStepper,
     ) -> Option<Vec<RatlineIndex>>;
 }
 
 #[enum_dispatch(PermuteRatlines)]
 pub enum RatlinesPermuter {
+    RatlineCuts(RatlineCutsRatlinePermuter),
     SccPermutations(SccPermutationsRatlinePermuter),
 }
 
@@ -29,48 +38,53 @@ impl RatlinesPermuter {
     pub fn new(
         autorouter: &mut Autorouter<impl AccessMesadata>,
         ratlines: Vec<RatlineIndex>,
+        presorter: SccIntersectionsAndLengthPresorter,
         options: &AutorouterOptions,
     ) -> Self {
         RatlinesPermuter::SccPermutations(SccPermutationsRatlinePermuter::new(
-            autorouter, ratlines, options,
+            autorouter, ratlines, presorter, options,
         ))
+        /*RatlinesPermuter::RatlineCuts(RatlineCutsRatlinePermuter::new(
+            autorouter, ratlines, presorter, options,
+        ))*/
     }
 }
 
 pub struct SccPermutationsRatlinePermuter {
-    sccs_permutations_iter: Permutations<std::vec::IntoIter<Vec<NodeIndex<usize>>>>,
-    ratlines: Vec<RatlineIndex>,
+    sccs_permutations_iter: Skip<Permutations<std::vec::IntoIter<Vec<NodeIndex<usize>>>>>,
+    original_ratlines: Vec<RatlineIndex>,
 }
 
 impl SccPermutationsRatlinePermuter {
     pub fn new(
-        autorouter: &mut Autorouter<impl AccessMesadata>,
+        _autorouter: &mut Autorouter<impl AccessMesadata>,
         ratlines: Vec<RatlineIndex>,
+        presorter: SccIntersectionsAndLengthPresorter,
         _options: &AutorouterOptions,
     ) -> Self {
         // TODO: Instead of instantiating presorter again here, get it from
         // an argument.
-        let presorter = SccIntersectionsAndLengthPresorter::new(autorouter, &ratlines);
         let sccs = presorter.dissolve();
         let sccs_len = sccs.len();
 
         Self {
-            sccs_permutations_iter: sccs.into_iter().permutations(sccs_len),
-            ratlines,
+            sccs_permutations_iter: sccs.into_iter().permutations(sccs_len).skip(1),
+            original_ratlines: ratlines,
         }
     }
 }
 
 impl PermuteRatlines for SccPermutationsRatlinePermuter {
-    fn next_ratlines_permutation(
+    fn permute_ratlines(
         &mut self,
         autorouter: &mut Autorouter<impl AccessMesadata>,
+        _stepper: &AutorouteExecutionStepper,
     ) -> Option<Vec<RatlineIndex>> {
         let scc_permutation = self.sccs_permutations_iter.next()?;
         let mut ratlines = vec![];
 
         for scc in scc_permutation {
-            for ratline in self.ratlines.iter() {
+            for ratline in self.original_ratlines.iter() {
                 if scc.contains(
                     &autorouter
                         .ratsnest()
@@ -94,3 +108,68 @@ impl PermuteRatlines for SccPermutationsRatlinePermuter {
         Some(ratlines)
     }
 }
+
+pub struct RatlineCutsRatlinePermuter {
+    //sccs: Vec<Vec<NodeIndex<usize>>>,
+}
+
+impl RatlineCutsRatlinePermuter {
+    pub fn new(
+        _autorouter: &mut Autorouter<impl AccessMesadata>,
+        _ratlines: Vec<RatlineIndex>,
+        _presorter: SccIntersectionsAndLengthPresorter,
+        _options: &AutorouterOptions,
+    ) -> Self {
+        /*Self {
+            sccs: presorter.dissolve(),
+        }*/
+        Self {}
+    }
+}
+
+impl PermuteRatlines for RatlineCutsRatlinePermuter {
+    fn permute_ratlines(
+        &mut self,
+        autorouter: &mut Autorouter<impl AccessMesadata>,
+        stepper: &AutorouteExecutionStepper,
+    ) -> Option<Vec<RatlineIndex>> {
+        let curr_ratline = stepper.ratlines()[*stepper.curr_ratline_index()];
+        let endpoint_dots = curr_ratline.ref_(autorouter).endpoint_dots();
+        let bands_cut_by_ratline: Vec<_> = autorouter
+            .board()
+            .layout()
+            .bands_between_nodes(
+                endpoint_dots
+                    .0
+                    .primitive(autorouter.board().layout().drawing())
+                    .layer(),
+                GenericNode::Primitive(endpoint_dots.0.into()),
+                GenericNode::Primitive(endpoint_dots.1.into()),
+            )
+            .collect();
+
+        // Find the first ratline corresponding to a band that is cut.
+        let first_cut_ratline_index = stepper
+            .ratlines()
+            .iter()
+            .position(|ratline| {
+                for (band_uid, _) in &bands_cut_by_ratline {
+                    if ratline.ref_(autorouter).band_termseg() == band_uid.0
+                        || ratline.ref_(autorouter).band_termseg() == band_uid.1
+                    {
+                        return true;
+                    }
+                }
+
+                false
+            })
+            .unwrap();
+
+        // Swap the first ratline corresponding to a band that is cut with the
+        // ratline that we have failed routing.
+        let mut ratlines = stepper.ratlines().clone();
+        ratlines.swap(*stepper.curr_ratline_index(), first_cut_ratline_index);
+
+        Some(ratlines)
+    }
+}

src/autorouter/presorter.rs

@@ -18,9 +18,9 @@ use crate::{
 #[enum_dispatch]
 pub trait PresortRatlines {
     fn presort_ratlines(
-        &mut self,
+        &self,
         autorouter: &mut Autorouter<impl AccessMesadata>,
-        ratlines: Vec<RatlineIndex>,
+        ratlines: &[RatlineIndex],
     ) -> Vec<RatlineIndex>;
 }
 
@@ -37,14 +37,13 @@ pub struct SccIntersectionsAndLengthPresorter {
 impl SccIntersectionsAndLengthPresorter {
     pub fn new(
         autorouter: &mut Autorouter<impl AccessMesadata>,
-        ratlines: &Vec<RatlineIndex>,
+        ratlines: &[RatlineIndex],
     ) -> Self {
         // FIXME: Unnecessary copy.
         let mut filtered_ratsnest = autorouter.ratsnest().graph().clone();
         filtered_ratsnest.retain_edges(|_g, i| ratlines.contains(&i));
 
         let mut sccs = tarjan_scc(&filtered_ratsnest);
-        let sccs_len = sccs.len();
 
         sccs.sort_unstable_by(|a, b| {
             // FIXME: These calculations should probably be stored somewhere
@@ -149,9 +148,9 @@ impl SccIntersectionsAndLengthPresorter {
 
 impl PresortRatlines for SccIntersectionsAndLengthPresorter {
     fn presort_ratlines(
-        &mut self,
+        &self,
         autorouter: &mut Autorouter<impl AccessMesadata>,
-        ratlines: Vec<RatlineIndex>,
+        ratlines: &[RatlineIndex],
     ) -> Vec<RatlineIndex> {
         let mut presorted_ratlines = vec![];
 

src/autorouter/ratline.rs

@@ -39,6 +39,16 @@ impl<'a, M: AccessMesadata> RatlineRef<'a, M> {
         Self { index, autorouter }
     }
 
+    pub fn band_termseg(&self) -> BandTermsegIndex {
+        self.autorouter
+            .ratsnest()
+            .graph()
+            .edge_weight(self.index)
+            .unwrap()
+            .band_termseg
+            .unwrap()
+    }
+
     pub fn endpoint_dots(&self) -> (FixedDotIndex, FixedDotIndex) {
         let (source, target) = self
             .autorouter

src/autorouter/ratsnest.rs

@@ -89,22 +89,23 @@ impl Ratsnest {
         let node_bound = layout.drawing().geometry().graph().node_bound();
 
         for layer in 0..layout.drawing().layer_count() {
-            let mut handle_rvw = |maybe_net: Option<usize>, vertex: RatvertexIndex, pos: Point| {
-                if let Some(net) = maybe_net {
-                    triangulations
-                        .entry((layer, net))
-                        .or_insert_with(|| Triangulation::new(node_bound))
-                        .add_vertex(RatvertexWeight { vertex, pos })?;
-                }
-                Ok(())
-            };
+            let mut handle_ratvertex_weight =
+                |maybe_net: Option<usize>, vertex: RatvertexIndex, pos: Point| {
+                    if let Some(net) = maybe_net {
+                        triangulations
+                            .entry((layer, net))
+                            .or_insert_with(|| Triangulation::new(node_bound))
+                            .add_vertex(RatvertexWeight { vertex, pos })?;
+                    }
+                    Ok(())
+                };
 
             for node in layout.drawing().layer_primitive_nodes(layer) {
                 if let PrimitiveIndex::FixedDot(dot) = node {
                     // Dots that are parts of polys are ignored because ratlines
                     // should only go to their centerpoints.
                     if layout.drawing().compounds(dot).next().is_none() {
-                        handle_rvw(
+                        handle_ratvertex_weight(
                             layout.drawing().primitive(dot).maybe_net(),
                             RatvertexIndex::FixedDot(dot),
                             node.primitive(layout.drawing()).shape().center(),
@@ -114,7 +115,7 @@ impl Ratsnest {
             }
 
             for poly in layout.layer_poly_nodes(layer) {
-                handle_rvw(
+                handle_ratvertex_weight(
                     layout.drawing().compound_weight(poly.into()).maybe_net(),
                     RatvertexIndex::Poly(poly),
                     poly.ref_(layout).shape().center(),