fix(experiment): score occupied perimeter cells including one-column cycles

crates/oa-core/examples/auto_layout_probe/condensed.rs

@@ -54,23 +54,49 @@ fn components(arcs: &[BTreeSet<usize>], work: &mut usize) -> Result<Vec<Vec<usiz
     Ok(result)
 }
 
-// Clockwise perimeter slots. Restrict to near-square physical envelopes when
-// possible; minimizing perimeter area without this restriction makes a strip.
+fn perimeter_slots(n: usize, rows: usize, cols: usize) -> Vec<(usize, usize)> {
+    let mut slots = Vec::new();
+    if rows == 1 {
+        slots.extend((0..cols).map(|col| (col, 0)));
+    } else if cols == 1 {
+        slots.extend((0..rows).map(|row| (0, row)));
+    } else {
+        slots.extend((0..cols).map(|col| (col, 0)));
+        slots.extend((1..rows).map(|row| (cols - 1, row)));
+        slots.extend((0..cols - 1).rev().map(|col| (col, rows - 1)));
+        slots.extend((1..rows - 1).rev().map(|row| (0, row)));
+    }
+    slots.truncate(n);
+    slots
+}
+
+// Score occupied maximum-member cells, excluding unused perimeter slots.
+// Heterogeneous members may occupy less than this nominal cell envelope.
 fn perimeter(
     n: usize,
     cell: Size,
     gap: Size,
     work: &mut usize,
 ) -> Result<(Vec<Position>, usize, usize), ModelError> {
-    let mut best: Option<((bool, f32, f32, usize, usize), usize, usize)> = None;
-    for rows in 2..=n.max(2) {
-        for cols in 2..=n.max(2) {
+    type GridScore = (bool, f32, f32, usize, usize);
+    let mut best: Option<(GridScore, usize, usize)> = None;
+    for rows in 1..=n {
+        for cols in 1..=n {
             charge(work, 1)?;
-            if 2 * rows + 2 * cols - 4 < n {
+            let capacity = if rows == 1 || cols == 1 {
+                rows * cols
+            } else {
+                2 * rows + 2 * cols - 4
+            };
+            if capacity < n {
                 continue;
             }
-            let width = cols as f32 * cell.width + (cols - 1) as f32 * gap.width;
-            let height = rows as f32 * cell.height + (rows - 1) as f32 * gap.height;
+            charge(work, capacity)?;
+            let slots = perimeter_slots(n, rows, cols);
+            let max_x = slots.iter().map(|p| p.0).max().unwrap();
+            let max_y = slots.iter().map(|p| p.1).max().unwrap();
+            let width = (max_x + 1) as f32 * cell.width + max_x as f32 * gap.width;
+            let height = (max_y + 1) as f32 * cell.height + max_y as f32 * gap.height;
             let aspect = (width / height).max(height / width);
             let key = (
                 aspect > 2.0,
@@ -89,19 +115,7 @@ fn perimeter(
         }
     }
     let (_, rows, cols) = best.ok_or_else(|| error("no perimeter grid"))?;
-    let mut slots = Vec::new();
-    for col in 0..cols {
-        slots.push((col, 0));
-    }
-    for row in 1..rows {
-        slots.push((cols - 1, row));
-    }
-    for col in (0..cols - 1).rev() {
-        slots.push((col, rows - 1));
-    }
-    for row in (1..rows - 1).rev() {
-        slots.push((0, row));
-    }
+    let slots = perimeter_slots(n, rows, cols);
     Ok((
         slots
             .into_iter()
@@ -548,4 +562,27 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn two_node_perimeter_scores_occupied_cells_instead_of_an_unused_row() {
+        let (positions, rows, cols) = perimeter(
+            2,
+            Size {
+                width: 224.0,
+                height: 160.0,
+            },
+            Size {
+                width: 250.0,
+                height: 56.0,
+            },
+            &mut 0,
+        )
+        .unwrap();
+        assert_eq!((rows, cols), (2, 1));
+        assert_eq!(
+            positions,
+            vec![Position { x: 0.0, y: 0.0 }, Position { x: 0.0, y: 216.0 }]
+        );
+        assert!(224.0_f32 / 376.0 > 0.5);
+    }
 }