Implemented algorithms for finding the dimension of a given poset (exact and heuristic based)

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "odis"
 version = "2026.4.0"
-authors = ["Dominik Dürrschnabel", "Armin Strupp"]
+authors = ["Dominik Dürrschnabel", "Armin Strupp", "Leo Englert"]
 edition = "2021"
 license = "AGPL-3.0-only"
 description = "Formal Concept Analysis algorithms and data structures"
@@ -41,3 +41,7 @@ harness = false
 [[bench]]
 name = "iceberg"
 harness = false
+
+[[bench]]
+name = "dimension"
+harness = false

README.md

@@ -85,6 +85,24 @@ let iceberg = Titanic.enumerate_named_concepts(&ctx, 3);
 `ExplorationMachine` drives interactive attribute exploration over a growing context.
 The state machine separates exploration logic from I/O.
 
+### Poset Dimension
+
+```rust
+use odis::algorithms::dimension;
+use odis::Poset;
+
+let p = Poset::<u32>::standard_example(3);
+
+// For smaller Posets
+let exact_dim_hybrid = dimension::Hybrid.dimension(p);
+
+// For larger Posets
+let exact_dim_sat = dimension::SatReduction.dimension(p);
+
+// for an upper bound (For larger Posets)
+let dim = dimension::GraphColoringHeuristic.dimension(p);
+```
+
 ## Formal context format
 
 Contexts are parsed from the [Burmeister `.cxt` format](https://fc-bug-search.uni-wuppertal.de/cxt-file-format):

benches/dimension.rs

@@ -0,0 +1,152 @@
+//! Scalability benchmarks for dimension algorithms.
+//!
+//! Excludes trivial posets (chains, antichains) that are recognized in O(1).
+//! Uses parameterized inputs (Criterion bench_with_input) to generate
+//! proper scaling curves in the Criterion HTML report.
+
+use criterion::{
+    black_box, criterion_group, criterion_main, AxisScale, BenchmarkId, Criterion,
+    PlotConfiguration,
+};
+use odis::{
+    algorithms::dimension::{GraphColoring, GraphColoringHeuristic, HypergraphColoring, Hybrid, SatReduction},
+    DimensionAlgorithm, Poset,
+};
+
+use rand::{Rng, SeedableRng};
+use std::time::Duration;
+
+// ─── Poset Generators ───────────────────────────────────────────────────
+
+fn standard_example(n: usize) -> Poset<u32> {
+    let nodes: Vec<u32> = (0..(2 * n) as u32).collect();
+    let mut edges = Vec::new();
+    for i in 0..n {
+        for j in 0..n {
+            if i != j {
+                edges.push((i as u32, (n + j) as u32));
+            }
+        }
+    }
+    Poset::from_covering_relation(nodes, edges).unwrap()
+}
+
+/// Random poset: n elements, edges i < j with probability p.
+fn random_poset(n: usize, edge_prob: f64, seed: u64) -> Poset<u32> {
+    let mut rng = rand::rngs::StdRng::seed_from_u64(seed);
+    let nodes: Vec<u32> = (0..n as u32).collect();
+    let mut edges = Vec::new();
+    for i in 0..n {
+        for j in i + 1..n {
+            if rng.gen_bool(edge_prob) {
+                edges.push((i as u32, j as u32));
+            }
+        }
+    }
+    Poset::from_transitive_relation(nodes, edges).unwrap()
+}
+
+// ─── Scaling Benchmarks ──────────────────────────────────────────────────
+
+fn bench_scaling_standard_examples(c: &mut Criterion) {
+    let mut group = c.benchmark_group("scaling_standard_examples");
+    group.measurement_time(Duration::from_secs(3));
+
+    // Set the plot to a logarithmic scale
+    group.plot_config(PlotConfiguration::default().summary_scale(AxisScale::Logarithmic));
+
+    for n in 2..=10usize {
+        let poset = standard_example(n);
+
+        group.bench_with_input(BenchmarkId::new("SAT", n), &n, |b, _| {
+            b.iter(|| SatReduction.dimension(black_box(&poset)))
+        });
+        group.bench_with_input(BenchmarkId::new("GCH", n), &n, |b, _| {
+            b.iter(|| GraphColoringHeuristic.dimension(black_box(&poset)))
+        });
+        group.bench_with_input(BenchmarkId::new("Hypergraph", n), &n, |b, _| {
+            b.iter(|| HypergraphColoring.dimension(black_box(&poset)))
+        });
+        group.bench_with_input(BenchmarkId::new("Graph", n), &n, |b, _| {
+            b.iter(|| GraphColoring.dimension(black_box(&poset)))
+        });
+        group.bench_with_input(BenchmarkId::new("Hybrid", n), &n, |b, _| {
+            b.iter(|| Hybrid.dimension(black_box(&poset)))
+        });
+    }
+    group.finish();
+}
+
+
+fn bench_scaling_random_posets(c: &mut Criterion) {
+    let mut group = c.benchmark_group("scaling_random_posets");
+    group.measurement_time(Duration::from_secs(3));
+    group.sample_size(20);
+
+    // Set the plot to a logarithmic scale
+    group.plot_config(PlotConfiguration::default().summary_scale(AxisScale::Logarithmic));
+
+    let sizes = [10, 20, 30, 40, 50, 60];
+    let density = 0.3;
+
+    for size in sizes {
+        let poset = random_poset(size, density, 42);
+
+        group.bench_with_input(BenchmarkId::new("SAT", size), &size, |b, _| {
+            b.iter(|| SatReduction.dimension(black_box(&poset)))
+        });
+
+        if size < 30 {
+            group.bench_with_input(BenchmarkId::new("Graph Coloring", size), &size, |b, _| {
+                b.iter(|| GraphColoring.dimension(black_box(&poset)))
+            });
+            group.bench_with_input(BenchmarkId::new("Hypergraph", size), &size, |b, _| {
+                b.iter(|| HypergraphColoring.dimension(black_box(&poset)))
+            });
+            group.bench_with_input(BenchmarkId::new("Hybrid", size), &size, |b, _| {
+                b.iter(|| Hybrid.dimension(black_box(&poset)))
+            });
+        }
+
+        group.bench_with_input(BenchmarkId::new("GCH", size), &size, |b, _| {
+            b.iter(|| GraphColoringHeuristic.dimension(black_box(&poset)))
+        });
+    }
+    group.finish();
+}
+
+fn bench_scaling_density(c: &mut Criterion) {
+    let mut group = c.benchmark_group("scaling_density");
+    group.measurement_time(Duration::from_secs(2));
+
+    // Set the plot to a logarithmic scale
+    group.plot_config(PlotConfiguration::default().summary_scale(AxisScale::Logarithmic));
+
+    let size = 20;
+    let densities = [0.1, 0.3, 0.5, 0.7, 0.9];
+
+    for p in densities {
+        let poset = random_poset(size, p, 1337);
+
+        let p_label = (p * 100.0) as u32;
+
+        group.bench_with_input(BenchmarkId::new("SAT", p_label), &p_label, |b, _| {
+            b.iter(|| SatReduction.dimension(black_box(&poset)))
+        });
+        group.bench_with_input(BenchmarkId::new("GCH", p_label), &p_label, |b, _| {
+            b.iter(|| GraphColoringHeuristic.dimension(black_box(&poset)))
+        });
+        group.bench_with_input(BenchmarkId::new("Hybrid", p_label), &p_label, |b, _| {
+            b.iter(|| Hybrid.dimension(black_box(&poset)))
+        });
+    }
+    group.finish();
+}
+
+criterion_group!(
+    benches,
+    bench_scaling_standard_examples,
+    bench_scaling_random_posets,
+    bench_scaling_density,
+);
+criterion_main!(benches);