Better Serialize and 3 Columns

include/l0_sampling/bucket.h

@@ -50,7 +50,7 @@ inline col_hash_t Bucket_Boruvka::get_index_depth(const vec_t update_idx, const
  const vec_hash_t max_depth) {
   col_hash_t depth_hash = col_hash(&update_idx, sizeof(vec_t), seed_and_col);
   depth_hash |= (1ull << max_depth); // assert not > max_depth by ORing
-  return __builtin_ctzl(depth_hash);
+  return __builtin_ctzll(depth_hash);
 }
 
 inline vec_hash_t Bucket_Boruvka::get_index_hash(const vec_t update_idx, const long sketch_seed) {

include/l0_sampling/sketch.h

@@ -14,10 +14,6 @@
 #include "../util.h"
 #include "bucket.h"
 
-// max number of non-zeroes in vector is n/2*n/2=n^2/4
-#define guess_gen(x) double_to_ull(log2(x) - 2)
-#define bucket_gen(d) double_to_ull((log2(d) + 1))
-
 enum SampleSketchRet {
   GOOD,  // querying this sketch returned a single non-zero value
   ZERO,  // querying this sketch returned that there are no non-zero values
@@ -34,7 +30,7 @@ class Sketch {
   static vec_t failure_factor;  // Pr(failure) = 1 / factor. Determines number of columns in sketch.
   static vec_t n;               // Length of the vector this is sketching.
   static size_t num_elems;      // length of our actual arrays in number of elements
-  static size_t num_buckets;    // Portion of array length, number of buckets
+  static size_t num_columns;    // Portion of array length, number of columns
   static size_t num_guesses;    // Portion of array length, number of guesses
 
   // Seed used for hashing operations in this sketch.
@@ -52,14 +48,14 @@ class Sketch {
   FRIEND_TEST(EXPR_Parallelism, N10kU100k);
 
   // Buckets of this sketch.
-  // Length is bucket_gen(failure_factor) * guess_gen(n).
+  // Length is column_gen(failure_factor) * guess_gen(n).
   // For buckets[i * guess_gen(n) + j], the bucket has a 1/2^j probability
   // of containing an index. The first two are pointers into the buckets array.
   alignas(vec_t) char buckets[];
 
   // private constructors -- use makeSketch
   Sketch(uint64_t seed);
-  Sketch(uint64_t seed, std::istream& binary_in);
+  Sketch(uint64_t seed, std::istream& binary_in, bool sparse);
   Sketch(const Sketch& s);
 
  public:
@@ -73,7 +69,7 @@ class Sketch {
    * @return           A pointer to a newly constructed sketch
    */
   static Sketch* makeSketch(void* loc, uint64_t seed);
-  static Sketch* makeSketch(void* loc, uint64_t seed, std::istream& binary_in);
+  static Sketch* makeSketch(void* loc, uint64_t seed, std::istream& binary_in, bool sparse=false);
 
   /**
    * Copy constructor to create a sketch from another
@@ -92,9 +88,9 @@ class Sketch {
   inline static void configure(vec_t _n, vec_t _factor) {
     n = _n;
     failure_factor = _factor;
-    num_buckets = bucket_gen(failure_factor);
+    num_columns = column_gen(failure_factor);
     num_guesses = guess_gen(n);
-    num_elems = num_buckets * num_guesses + 1;  // +1 for zero bucket optimization
+    num_elems = num_columns * num_guesses + 1;  // +1 for zero bucket optimization
   }
 
   inline static size_t sketchSizeof() {
@@ -110,6 +106,8 @@ class Sketch {
 
   inline void reset_queried() { already_queried = false; }
 
+  inline static size_t get_columns() { return num_columns; }
+
   /**
    * Update a sketch based on information about one of its indices.
    * @param update the point update.
@@ -124,11 +122,19 @@ class Sketch {
 
   /**
    * Function to query a sketch.
-   * @return   A pair with the result index and a code indicating if the type of result.
+   * @return   A pair with the result index and a code indicating the type of result.
    */
   std::pair<vec_t, SampleSketchRet> query();
 
+  /*
+   * Function to query all columns within a sketch to return 1 or more non-zero indices
+   * @return   A pair with the result indices and a code indicating the type of result.
+   */
+  std::pair<std::vector<vec_t>, SampleSketchRet> exhaustive_query();
+
   inline uint64_t get_seed() const { return seed; }
+  inline size_t column_seed(size_t column_idx) const { return seed + column_idx*5; }
+  inline size_t checksum_seed() const { return seed; }
 
   /**
    * Operator to add a sketch to another one in-place. Guaranteed to be
@@ -144,10 +150,24 @@ class Sketch {
 
   /**
    * Serialize the sketch to a binary output stream.
-   * @param out the stream to write to.
+   * @param binary_out   the stream to write to.
    */
   void write_binary(std::ostream& binary_out);
   void write_binary(std::ostream& binary_out) const;
+
+  /**
+   * Serialize a sketch while optimizing for space
+   * This assumes that the sketch itself sparse
+   * Otherwise, this serialization will use more space
+   * @param binary_out   the stream to write to.
+   */
+  void write_sparse_binary(std::ostream& binary_out);
+  void write_sparse_binary(std::ostream& binary_out) const;
+
+
+  // max number of non-zeroes in vector is n/2*n/2=n^2/4
+  static size_t guess_gen(size_t x) { return double_to_ull(log2(x) - 2); }
+  static size_t column_gen(size_t d) { return double_to_ull((log2(d) + 1)); }
 };
 
 class MultipleQueryException : public std::exception {

include/supernode.h

@@ -5,21 +5,28 @@
 
 #include "l0_sampling/sketch.h"
 
+enum SerialType {
+  FULL,
+  PARTIAL,
+  SPARSE,
+};
+
 /**
  * This interface implements the "supernode" so Boruvka can use it as a black
  * box without needing to worry about implementing l_0.
  */
 class Supernode {
-  // the size of a super-node in bytes including the all sketches off the end
-  static size_t bytes_size; 
+  static size_t max_sketches;
+  static size_t bytes_size; // the size of a super-node in bytes including the sketches
   static size_t serialized_size; // the size of a supernode that has been serialized
-  int idx;
-  int num_sketches;
+  size_t sample_idx;
   std::mutex node_mt;
 
   FRIEND_TEST(SupernodeTestSuite, TestBatchUpdate);
   FRIEND_TEST(SupernodeTestSuite, TestConcurrency);
   FRIEND_TEST(SupernodeTestSuite, TestSerialization);
+  FRIEND_TEST(SupernodeTestSuite, TestPartialSparseSerialization);
+  FRIEND_TEST(SupernodeTestSuite, SketchesHaveUniqueSeeds);
   FRIEND_TEST(GraphTestSuite, TestCorrectnessOfReheating);
   FRIEND_TEST(GraphTest, TestSupernodeRestoreAfterCCFailure);
   FRIEND_TEST(EXPR_Parallelism, N10kU100k);
@@ -29,6 +36,7 @@ class Supernode {
   const uint64_t seed; // for creating a copy
 
 private:
+  size_t num_sketches;
   size_t sketch_size;
 
   /* collection of logn sketches to query from, since we can't query from one
@@ -79,10 +87,11 @@ class Supernode {
 
   ~Supernode();
 
-  static inline void configure(uint64_t n, vec_t sketch_fail_factor=100) {
+  static inline void configure(uint64_t n, vec_t sketch_fail_factor=default_fail_factor) {
     Sketch::configure(n*n, sketch_fail_factor);
-    bytes_size = sizeof(Supernode) + size_t(log2(n)/(log2(3)-1)) * Sketch::sketchSizeof();
-    serialized_size = size_t(log2(n)/(log2(3)-1)) * Sketch::serialized_size();
+    max_sketches = log2(n)/(log2(3)-1);
+    bytes_size = sizeof(Supernode) + max_sketches * Sketch::sketchSizeof();
+    serialized_size = max_sketches * Sketch::serialized_size();
   }
 
   static inline size_t get_size() {
@@ -98,28 +107,28 @@ class Supernode {
     return sketch_size;
   }
 
-  // return the number of sketches held in this supernode
-  int get_num_sktch() { return num_sketches; };
+  // return the maximum number of sketches held in by a Supernode
+  // most Supernodes will hold this many sketches
+  static int get_max_sketches() { return max_sketches; };
+
+  // get number of samples remaining in the Supernode
+  int samples_remaining() { return num_sketches - sample_idx; }
 
   inline bool out_of_queries() {
-    return idx == num_sketches;
+    return sample_idx >= num_sketches;
   }
 
   inline int curr_idx() {
-    return idx;
-  }
-
-  inline void incr_idx() {
-    ++idx;
+    return sample_idx;
   }
 
   // reset the supernode query metadata
   // we use this when resuming insertions after CC made copies in memory
   inline void reset_query_state() { 
-    for (int i = 0; i < idx; i++) {
+    for (size_t i = 0; i < sample_idx; i++) {
       get_sketch(i)->reset_queried();
     }
-    idx = 0;
+    sample_idx = 0;
   }
 
   // get the ith sketch in the sketch array as a const object
@@ -135,6 +144,15 @@ class Supernode {
    */
   std::pair<Edge, SampleSketchRet> sample();
 
+  /**
+   * Function to sample 1 or more edges from the cut of a supernode.
+   * This function runs a query that samples from all columns in a single Sketch
+   * @return    an list of edges in the cut, each represented as an Edge with LHS <= RHS,
+   *            if one exists. Additionally, returns a code represnting the sample
+   *            result (good, zero, or fail)
+   */
+  std::pair<std::vector<Edge>, SampleSketchRet> exhaustive_sample();
+
   /**
    * In-place merge function. Guaranteed to update the caller Supernode.
    */
@@ -166,9 +184,21 @@ class Supernode {
 
   /**
    * Serialize the supernode to a binary output stream.
-   * @param out the stream to write to.
+   * @param binary_out   the stream to write to.
+   */
+  void write_binary(std::ostream &binary_out, bool sparse = false);
+
+  /*
+   * Serialize a portion of the supernode to a binary output stream.
+   * @param binary_out  the stream to write to.
+   * @param beg         the index of the first sketch to serialize
+   * @param num         the number of sketches to serialize
    */
-  void write_binary(std::ostream &binary_out);
+  void write_binary_range(std::ostream&binary_out, uint32_t beg, uint32_t num, bool sparse = false);
+
+  // void write_sparse_binary_range(std::ostream&binary_out, uint32_t beg, uint32_t end);
+
+  static constexpr size_t default_fail_factor = 4;
 };
 
 

include/test/sketch_constructors.h

@@ -14,10 +14,10 @@ SketchUniquePtr makeSketch(long seed) {
   };
 }
 
-SketchUniquePtr makeSketch(long seed, std::fstream &binary_in) {
+SketchUniquePtr makeSketch(long seed, std::fstream &binary_in, bool sparse=false) {
   void* loc = malloc(Sketch::sketchSizeof());
   return {
-    Sketch::makeSketch(loc, seed, binary_in),
+    Sketch::makeSketch(loc, seed, binary_in, sparse),
     [](Sketch* s){ free(s); }
   };
 }

include/types.h

@@ -18,6 +18,12 @@ enum UpdateType {
 struct Edge {
   node_id_t src = 0;
   node_id_t dst = 0;
+
+  bool operator< (const Edge&oth) const {
+    if (src == oth.src)
+      return dst < oth.dst;
+    return src < oth.src;
+  }
 };
 
 struct GraphUpdate {