improvise-jq0m: a small span narrows per covered item, not by the whole category; grouped bench cases

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze

benches/grid_projection.rs

@@ -54,6 +54,50 @@ fn dense_app(regions: usize, products: usize, measures: usize) -> App {
     app
 }
 
+/// Days in collapsed groups of `per_group` on Row, with Product: every row is a
+/// fold over a few days, never the whole category (improvise-jq0m).
+fn grouped_app(days: usize, per_group: usize, products: usize, measures: usize) -> App {
+    let mut wb = Workbook::new("Grouped");
+    wb.add_category("Day").unwrap();
+    wb.add_category("Product").unwrap();
+    for d in 0..days {
+        let group = format!("G{}", d / per_group);
+        wb.add_item_in_group("Day", format!("Day{d}"), group).unwrap();
+    }
+    for p in 0..products {
+        wb.add_item("Product", format!("Product{p}")).unwrap();
+    }
+    for m in 0..measures {
+        wb.add_item("_Measure", format!("Measure{m}")).unwrap();
+    }
+    {
+        let v = wb.active_view_mut();
+        v.set_axis("Day", Axis::Row);
+        v.set_axis("Product", Axis::Row);
+        v.set_axis("_Measure", Axis::Column);
+        for g in 0..days.div_ceil(per_group) {
+            v.toggle_group_collapse("Day", &format!("G{g}"));
+        }
+    }
+    let mut n = 0.0f64;
+    for d in 0..days {
+        for p in 0..products {
+            for m in 0..measures {
+                n += 1.0;
+                let key = CellKey::new(vec![
+                    ("Day".to_string(), format!("Day{d}")),
+                    ("Product".to_string(), format!("Product{p}")),
+                    ("_Measure".to_string(), format!("Measure{m}")),
+                ]);
+                wb.model.set_cell(key, CellValue::Number(n));
+            }
+        }
+    }
+    let mut app = App::new(wb, None);
+    app.rebuild_layout();
+    app
+}
+
 fn whole_grid(app: &App) -> Viewport {
     Viewport {
         row_offset: 0,
@@ -105,7 +149,10 @@ fn time_widths(iters: u32, app: &App) -> Duration {
 }
 
 fn case(label: &str, regions: usize, products: usize, measures: usize, iters: u32) {
-    let app = dense_app(regions, products, measures);
+    report(label, dense_app(regions, products, measures), iters);
+}
+
+fn report(label: &str, app: App, iters: u32) {
     let rows = app.layout.row_count();
     let cols = app.layout.col_count();
     let cells = rows * cols;
@@ -139,4 +186,8 @@ fn main() {
     case("large", 60, 20, 8, 50);
     case("18k cells (gotcha 41)", 150, 20, 6, 20);
     case("pathological", 300, 30, 10, 5);
+    println!("\ncollapsed small groups on the row axis (improvise-jq0m)\n");
+    report("364 days in weeks", grouped_app(364, 7, 20, 6), 5);
+    report("364 days in pairs", grouped_app(364, 2, 20, 6), 5);
+    report("1000 days in pairs", grouped_app(1000, 2, 10, 4), 3);
 }