From d02fe67962c8002ddc6e0d6569128ae2645ea7fc Mon Sep 17 00:00:00 2001
From: Douglas Rumbaugh <dbr4@psu.edu>
Date: Mon, 24 Jul 2023 16:49:21 -0400
Subject: VPTree: fixed knn query

---
 include/ds/PriorityQueue.h          |   6 +-
 include/framework/RecordInterface.h |  10 ++-
 include/shard/VPTree.h              | 136 +++++++++++++++++++++++-------------
 tests/vptree_tests.cpp              |  74 +++++++++++++++++---
 4 files changed, 164 insertions(+), 62 deletions(-)

diff --git a/include/ds/PriorityQueue.h b/include/ds/PriorityQueue.h
index a8e9ba5..4612eef 100644
--- a/include/ds/PriorityQueue.h
+++ b/include/ds/PriorityQueue.h
@@ -23,6 +23,7 @@ struct queue_record {
 template <typename R>
 class standard_minheap {
 public:
+    standard_minheap(R *baseline) {}
     inline bool operator()(const R* a, const R* b) {
         return *a < *b;
     }
@@ -31,6 +32,7 @@ public:
 template <typename R>
 class standard_maxheap {
 public:
+    standard_maxheap(R *baseline) {}
     inline bool operator()(const R* a, const R* b) {
         return *a > *b;
     }
@@ -39,7 +41,8 @@ public:
 template <typename R, typename CMP=standard_minheap<R>>
 class PriorityQueue {
 public:
-    PriorityQueue(size_t size) : data(size), tail(0) {}
+    PriorityQueue(size_t size, R* cmp_baseline=nullptr) : data(size), tail(0), cmp(cmp_baseline) {}
+
     ~PriorityQueue() = default;
 
     size_t size() const {
@@ -97,6 +100,7 @@ private:
     std::vector<queue_record<R>> data;
     CMP cmp;
     size_t tail;
+    R *baseline;
 
     /*
      * Swap the elements at position a and position
diff --git a/include/framework/RecordInterface.h b/include/framework/RecordInterface.h
index 85a0794..cea9fbe 100644
--- a/include/framework/RecordInterface.h
+++ b/include/framework/RecordInterface.h
@@ -49,6 +49,7 @@ concept WrappedInterface = RecordInterface<R> && requires(R r, R s, bool b) {
     {r.set_tombstone(b)};
     {r.is_tombstone()} -> std::convertible_to<bool>;
     {r < s} -> std::convertible_to<bool>;
+    {r == s} ->std::convertible_to<bool>;
 };
 
 template<RecordInterface R>
@@ -79,6 +80,11 @@ struct Wrapped {
     inline bool operator<(const Wrapped& other) const {
         return rec < other.rec || (rec == other.rec && header < other.header);
     }
+
+    inline bool operator==(const Wrapped& other) const {
+        return rec == other.rec;
+    }
+
 };
 
 template <typename K, typename V>
@@ -185,10 +191,10 @@ struct EuclidPoint{
     inline double calc_distance(const EuclidPoint& other) const {
         double dist = 0;
         for (size_t i=0; i<D; i++) {
-            dist += pow(data[i] - other.data[i], 2);
+            dist += (data[i] - other.data[i]) * (data[i] - other.data[i]);
         }
         
-        return sqrt(dist);
+        return std::sqrt(dist);
     }
 };
 
diff --git a/include/shard/VPTree.h b/include/shard/VPTree.h
index 05ffd50..927108c 100644
--- a/include/shard/VPTree.h
+++ b/include/shard/VPTree.h
@@ -46,26 +46,56 @@ struct KNNState {
 
 template <NDRecordInterface R>
 struct KNNBufferState {
-    size_t cutoff;
-    size_t sample_size;
-    Alias* alias;
-    decltype(R::weight) max_weight;
-    decltype(R::weight) total_weight;
-
-    ~KNNBufferState() {
-        delete alias;
+
+};
+
+
+template <typename R>
+class KNNDistCmpMax {
+public:
+    KNNDistCmpMax(R *baseline) : P(baseline) {}
+
+    inline bool operator()(const R *a, const R *b) requires WrappedInterface<R> {
+        return a->rec.calc_distance(P->rec) > b->rec.calc_distance(P->rec); 
+    }
+
+    inline bool operator()(const R *a, const R *b) requires (!WrappedInterface<R>){
+        return a->calc_distance(*P) > b->calc_distance(*P); 
+    }
+
+private:
+    R *P;
+};
+
+template <typename R>
+class KNNDistCmpMin {
+public:
+    KNNDistCmpMin(R *baseline) : P(baseline) {}
+
+    inline bool operator()(const R *a, const R *b) requires WrappedInterface<R> {
+        return a->rec.calc_distance(P->rec) < b->rec.calc_distance(P->rec); 
+    }
+
+    inline bool operator()(const R *a, const R *b) requires (!WrappedInterface<R>){
+        return a->calc_distance(*P) < b->calc_distance(*P); 
     }
 
+private:
+    R *P;
 };
 
+
+
 template <NDRecordInterface R>
 class VPTree {
 private:
     struct vpnode {
-        size_t idx = 0;
-        double radius = 0;
-        vpnode *inside = nullptr;
-        vpnode *outside = nullptr;
+        size_t idx;
+        double radius;
+        vpnode *inside;
+        vpnode *outside;
+
+        vpnode(size_t idx) : idx(idx), radius(0), inside(nullptr), outside(nullptr) {}
 
         ~vpnode() {
             delete inside;
@@ -180,15 +210,17 @@ public:
 private:
 
     vpnode *build_vptree() {
-        assert(m_reccnt > 0);
+        if (m_reccnt == 0) {
+            return nullptr;
+        }
 
         size_t lower = 0;
         size_t upper = m_reccnt - 1;
 
         auto rng = gsl_rng_alloc(gsl_rng_mt19937);
-        auto n = build_subtree(lower, upper, rng);
+        auto root = build_subtree(lower, upper, rng);
         gsl_rng_free(rng);
-        return n;
+        return root;
     }
 
     void build_map() {
@@ -204,32 +236,42 @@ private:
     }
 
     vpnode *build_subtree(size_t start, size_t stop, gsl_rng *rng) {
-        if (start >= stop) {
+        // base-case: sometimes happens (probably because of the +1 and -1
+        // in the first recursive call)
+        if (start > stop) {
             return nullptr;
         }
 
-        // select a random element to partition based on, and swap
-        // it to the front of the sub-array
-        auto i = start + gsl_rng_uniform_int(rng, stop - start);
+        // base-case: create a leaf node
+        if (start == stop) {
+            vpnode *node = new vpnode(start);
+            node->idx = start;
+
+            m_node_cnt++;
+
+            return node;
+        }
+
+        // select a random element to be the root of the
+        // subtree
+        auto i = start + gsl_rng_uniform_int(rng, stop - start + 1);
         swap(start, i);
 
         // partition elements based on their distance from the start,
         // with those elements with distance falling below the median
         // distance going into the left sub-array and those above 
         // the median in the right. This is easily done using QuickSelect.
-        auto mid = ((start+1) + stop) / 2;
+        auto mid = (start + 1 + stop) / 2;
         quickselect(start + 1, stop, mid, m_data[start], rng);
 
         // Create a new node based on this partitioning
-        vpnode *node = new vpnode();
+        vpnode *node = new vpnode(start);
 
-        // store the radius of the circle used for partitioning the
-        // node.
-        node->idx = start;
+        // store the radius of the circle used for partitioning the node.
         node->radius = m_data[start].rec.calc_distance(m_data[mid].rec);
 
         // recursively construct the left and right subtrees
-        node->inside = build_subtree(start + 1, mid - 1, rng); 
+        node->inside = build_subtree(start + 1, mid-1, rng); 
         node->outside = build_subtree(mid, stop, rng);
 
         m_node_cnt++;
@@ -277,35 +319,38 @@ private:
     }
 
 
-    void search(vpnode *node, const R &point, size_t k, PriorityQueue<R> &pq, double *farthest) {
+    void search(vpnode *node, const R &point, size_t k, PriorityQueue<Wrapped<R>, KNNDistCmpMax<Wrapped<R>>> &pq, double *farthest) {
         if (node == nullptr) return;
 
         double d = point.calc_distance(m_data[node->idx].rec);
 
         if (d < *farthest) {
-            if (pq.size() == k) pq.pop();
+            if (pq.size() == k) {
+                auto t = pq.peek().data->rec;
+                pq.pop();
+            }
             pq.push(&m_data[node->idx]);
             if (pq.size() == k) {
-                *farthest = point.calc_distance(*pq.peek().data.rec);
+                *farthest = point.calc_distance(pq.peek().data->rec);
             }
         }
 
         if (!node->inside && !node->outside) return;
 
         if (d < node->radius) {
-            if (d - *farthest <= node->radius) {
+            if (d - (*farthest) <= node->radius) {
                 search(node->inside, point, k, pq, farthest);
             }
 
-            if (d + *farthest >= node->radius) {
+            if (d + (*farthest) >= node->radius) {
                 search(node->outside, point, k, pq, farthest);
             }
         } else {
-            if (d + *farthest >= node->radius) {
+            if (d + (*farthest) >= node->radius) {
                 search(node->outside, point, k, pq, farthest);
             }
 
-            if (d - *farthest <= node->radius) {
+            if (d - (*farthest) <= node->radius) {
                 search(node->inside, point, k, pq, farthest);
             }
         }
@@ -320,17 +365,6 @@ private:
     vpnode *m_root;
 };
 
-template <NDRecordInterface R, R P>
-class KNNDistCmp {
-public:
-    inline bool operator()(queue_record<R> *a, queue_record<R> *b) requires WrappedInterface<R> {
-        return a->rec.calc_distance(P.rec) > b->rec.calc_distance(P.rec); 
-    }
-
-    inline bool operator()(queue_record<R> *a, queue_record<R> *b) requires (!WrappedInterface<R>){
-        return a->data.calc_distance(P) > b->data.calc_distance(P); 
-    }
-};
 
 template <NDRecordInterface R>
 class KNNQuery {
@@ -354,7 +388,7 @@ public:
         wrec.rec = p->point;
         wrec.header = 0;
 
-        PriorityQueue<Wrapped<R>, KNNDistCmp<Wrapped<R>, wrec>> pq;
+        PriorityQueue<Wrapped<R>, KNNDistCmpMax<Wrapped<R>>> pq(p->k, &wrec);
 
         double farthest = std::numeric_limits<double>::max();
 
@@ -376,18 +410,18 @@ public:
 
         size_t k = p->k;
 
-        PriorityQueue<Wrapped<R>, KNNDistCmp<Wrapped<R>, wrec>> pq;
+        PriorityQueue<Wrapped<R>, KNNDistCmpMax<Wrapped<R>>> pq(k, &wrec);
         for (size_t i=0; i<buffer->get_record_count(); i++) {
             // Skip over deleted records (under tagging)
-            if (buffer->get_data()[i]->is_deleted()) {
+            if ((buffer->get_data())[i].is_deleted()) {
                 continue;
             }
 
             if (pq.size() < k) {
                 pq.push(buffer->get_data() + i);
             } else {
-                double head_dist = pq.peek().data.rec->calc_distance(wrec.rec);
-                double cur_dist = (buffer->get_data() + i)->calc_distance(wrec.rec);
+                double head_dist = pq.peek().data->rec.calc_distance(wrec.rec);
+                double cur_dist = (buffer->get_data() + i)->rec.calc_distance(wrec.rec);
 
                 if (cur_dist < head_dist) {
                     pq.pop();
@@ -398,9 +432,11 @@ public:
 
         std::vector<Wrapped<R>> results;
         while (pq.size() > 0) {
-            results.emplace(*pq.peek().data);
+            results.emplace_back(*(pq.peek().data));
             pq.pop();
         }
+
+        return results;
     }
 
     static std::vector<R> merge(std::vector<std::vector<R>> &results, void *parms) {
@@ -408,7 +444,7 @@ public:
         R rec = p->point;
         size_t k = p->k;
 
-        PriorityQueue<R, KNNDistCmp<R, rec>> pq;
+        PriorityQueue<R, KNNDistCmpMax<R>> pq(k, &rec);
         for (size_t i=0; i<results.size(); i++) {
             for (size_t j=0; j<results.size(); j++) {
                 if (pq.size() < k) {
diff --git a/tests/vptree_tests.cpp b/tests/vptree_tests.cpp
index b86e1e9..894e64a 100644
--- a/tests/vptree_tests.cpp
+++ b/tests/vptree_tests.cpp
@@ -11,6 +11,7 @@
 
 #include "shard/VPTree.h"
 #include "testing.h"
+#include "vptree.hpp"
 
 #include <check.h>
 
@@ -108,6 +109,65 @@ START_TEST(t_point_lookup_miss)
 }
 
 
+START_TEST(t_buffer_query) 
+{
+    size_t n = 10000;
+    auto buffer = create_2d_sequential_mbuffer(n);
+
+    PRec target;
+    target.data[0] = 120;
+    target.data[1] = 120;
+
+    KNNQueryParms<PRec> p;
+    p.k = 10;
+    p.point = target;
+
+    auto state = KNNQuery<PRec>::get_buffer_query_state(buffer, &p);
+    auto result = KNNQuery<PRec>::buffer_query(buffer, state, &p);
+    KNNQuery<PRec>::delete_buffer_query_state(state);
+
+    std::sort(result.begin(), result.end());
+    size_t start = 120 - 5;
+    for (size_t i=0; i<result.size(); i++) {
+        ck_assert_int_eq(result[i].rec.data[0], start++);
+    }
+
+    delete buffer;
+}
+
+START_TEST(t_knn_query) 
+{
+    size_t n = 100;
+    auto buffer = create_2d_sequential_mbuffer(n);
+
+    PRec target;
+    target.data[0] = 50;
+    target.data[1] = 50;
+
+    KNNQueryParms<PRec> p;
+    p.k = 10;
+    p.point = target;
+
+    auto state = KNNQuery<PRec>::get_buffer_query_state(buffer, &p);
+    auto result = KNNQuery<PRec>::buffer_query(buffer, state, &p);
+
+    KNNQuery<PRec>::delete_buffer_query_state(state);
+
+    auto vptree = VPTree<PRec>(buffer);
+    auto state_2 = KNNQuery<PRec>::get_query_state(&vptree, &p);
+    auto result_2 = KNNQuery<PRec>::query(&vptree, state_2, &p);
+    KNNQuery<PRec>::delete_query_state(state_2);
+
+    std::sort(result_2.begin(), result_2.end());
+    size_t start = 46;
+    for (size_t i=0; i<result_2.size(); i++) {
+        ck_assert_int_eq(result_2[i].rec.data[0], start++);
+    }
+
+    delete buffer;
+}
+
+
 Suite *unit_testing()
 {
     Suite *unit = suite_create("VPTree Shard Unit Testing");
@@ -121,18 +181,14 @@ Suite *unit_testing()
 
     TCase *lookup = tcase_create("de:VPTree:point_lookup Testing");
     tcase_add_test(lookup, t_point_lookup);
-    //tcase_add_test(lookup, t_point_lookup_miss);
+    tcase_add_test(lookup, t_point_lookup_miss);
     suite_add_tcase(unit, lookup);
 
 
-    /*
-    TCase *sampling = tcase_create("de:VPTree::VPTreeQuery Testing");
-    tcase_add_test(sampling, t_wss_query);
-    tcase_add_test(sampling, t_wss_query_merge);
-    tcase_add_test(sampling, t_wss_buffer_query_rejection);
-    tcase_add_test(sampling, t_wss_buffer_query_scan);
-    suite_add_tcase(unit, sampling);
-    */
+    TCase *query = tcase_create("de:VPTree::VPTreeQuery Testing");
+    tcase_add_test(query, t_buffer_query);
+    tcase_add_test(query, t_knn_query);
+    suite_add_tcase(unit, query);
 
     return unit;
 }
-- 
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