Patched sketching corner cases

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "hyperloglog-rs"
-version = "0.1.50"
+version = "0.1.51"
 edition = "2021"
 authors = ["Luca Cappelletti <[email protected]>"]
 description = "A Rust implementation of HyperLogLog trying to be parsimonious with memory."

src/hyper_spheres_sketch.rs

@@ -74,6 +74,8 @@ impl<F: Primitive<f32>, PRECISION: Precision + WordType<BITS>, const BITS: usize
             union_zeros,
         ));
 
+        // union_estimate = union_estimate.get_min(self_cardinality + other_cardinality);
+
         EstimatedUnionCardinalities::from((self_cardinality, other_cardinality, union_estimate))
     }
 
@@ -171,6 +173,7 @@ where
                 right_difference_cardinality_vector[j] = (euc.get_right_difference_cardinality()
                     - last_right_difference)
                     .get_max(I::default());
+
                 last_right_difference = euc.get_right_difference_cardinality();
             }
             left_difference_cardinality_vector[i] = (euc.get_left_difference_cardinality()
@@ -255,42 +258,40 @@ where
                 );
 
                 let maximal_differential_intersection_cardinality =
-                    (euc.get_left_difference_cardinality() - last_left_difference)
-                        .get_max(I::default())
-                        + (right_cardinality - last_right_cardinality).get_max(I::default());
-
-                debug_assert!(
-                    maximal_differential_intersection_cardinality >= differential_intersection,
-                    concat!(
-                        "Expected maximal_differential_intersection_cardinality to be larger than differential_intersection, but it is not. ",
-                        "Got: maximal_differential_intersection_cardinality: {:?}, differential_intersection: {:?}",
-                    ),
-                    maximal_differential_intersection_cardinality,
-                    differential_intersection,
-                );
-
-                differential_overlap_cardinality_matrix[i][j] = differential_intersection
-                    / maximal_differential_intersection_cardinality
+                    (euc.get_left_difference_cardinality() - last_left_difference
+                        + right_cardinality
+                        - last_right_cardinality)
                         .get_max(I::non_zero_positive_min_value());
+
+                differential_overlap_cardinality_matrix[i][j] = (differential_intersection
+                    / maximal_differential_intersection_cardinality)
+                    .get_min(I::ONE);
                 last_row[j] = euc.get_intersection_cardinality().get_max(delta);
                 comulative_row += differential_intersection;
 
                 // We always set the value of the right difference so that the
                 // last time we write this will necessarily be with the last
                 // and largest left set.
-                right_difference_cardinality_vector[j] = (euc.get_right_difference_cardinality()
+
+                let differential_right_difference = (euc.get_right_difference_cardinality()
                     - last_right_difference)
-                    .get_max(I::default())
-                    / (right_cardinality - last_right_cardinality)
-                        .get_max(I::non_zero_positive_min_value());
+                    .get_max(I::default());
+                let maximal_differential_right_difference = (right_cardinality
+                    - last_right_cardinality)
+                    .get_max(I::non_zero_positive_min_value());
+
+                right_difference_cardinality_vector[j] = (differential_right_difference
+                    / maximal_differential_right_difference)
+                    .get_min(I::ONE);
                 last_right_difference = euc.get_right_difference_cardinality();
                 last_right_cardinality = right_cardinality;
             }
-            left_difference_cardinality_vector[i] = (euc.get_left_difference_cardinality()
+            left_difference_cardinality_vector[i] = ((euc.get_left_difference_cardinality()
                 - last_left_difference)
                 .get_max(I::default())
                 / (left_cardinality - last_left_cardinality)
-                    .get_max(I::non_zero_positive_min_value());
+                    .get_max(I::non_zero_positive_min_value()))
+            .get_min(I::ONE);
             last_left_cardinality = left_cardinality;
             last_left_difference = euc.get_left_difference_cardinality();
         }

tests/test_hyper_spheres_sketch.rs

@@ -68,7 +68,7 @@ fn get_random_hyper_spheres_hll<const N: usize>(
 
 #[test]
 fn test_hyper_spheres_sketch() {
-    let number_of_tests = 1_00;
+    let number_of_tests = 100;
 
     // We run multiple MSE to have an estimate of how much the
     // HyperLogLog approximation is off when compared to the
@@ -222,9 +222,11 @@ fn test_hyper_spheres_sketch() {
                 left_diff_normalized_hll[i] <= 1.0,
                 concat!(
                     "We expect the left difference cardinality vector to ",
-                    "have values less than or equal to 1.0 but we got {:?} instead."
+                    "have values less than or equal to 1.0 but we got {:?} instead. ",
+                    "This happened in position {:?}."
                 ),
-                left_diff_normalized_hll[i]
+                left_diff_normalized_hll[i],
+                i
             );
 
             assert!(
@@ -255,9 +257,11 @@ fn test_hyper_spheres_sketch() {
                 right_diff_normalized_hll[i] <= 1.0,
                 concat!(
                     "We expect the right difference cardinality vector to ",
-                    "have values less than or equal to 1.0 but we got {:?} instead."
+                    "have values less than or equal to 1.0 but we got {:?} instead. ",
+                    "This happened in position {:?}."
                 ),
-                right_diff_normalized_hll[i]
+                right_diff_normalized_hll[i],
+                i
             );
 
             assert!(