[incubator-datasketches-website] branch master updated: HLL C++ example

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The following commit(s) were added to refs/heads/master by this push:
     new c1ffb43  HLL C++ example
c1ffb43 is described below

commit c1ffb43c44d58eaa3bb1be679b89eac5a9249aba
Author: AlexanderSaydakov <Al...@users.noreply.github.com>
AuthorDate: Thu Mar 12 17:50:13 2020 -0700

    HLL C++ example
---
 docs/HLL/HllCppExample.md | 88 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)

diff --git a/docs/HLL/HllCppExample.md b/docs/HLL/HllCppExample.md
new file mode 100644
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--- /dev/null
+++ b/docs/HLL/HllCppExample.md
@@ -0,0 +1,88 @@
+---
+layout: doc_page
+---
+<!--
+    Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you under the Apache License, Version 2.0 (the
+    "License"); you may not use this file except in compliance
+    with the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing,
+    software distributed under the License is distributed on an
+    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+    KIND, either express or implied.  See the License for the
+    specific language governing permissions and limitations
+    under the License.
+-->
+# Hyper Log Log Sketch C++ Example
+
+    #include <iostream>
+    #include <fstream>
+    
+    #include <hll.hpp>
+    
+    //simplified file operations and no error handling for clarity
+    int main(int argc, char **argv) {
+      const int lg_k = 11;
+      const auto type = datasketches::HLL_4; // this is the default, but explicit here for illustration
+    
+      // this section generates two sketches with some overlap and serializes them into files
+      {
+        // 100000 distinct keys
+        datasketches::hll_sketch sketch1(lg_k, type); // type is optional, defaults to HLL_4
+        for (int key = 0; key < 100000; key++) sketch1.update(key);
+        std::ofstream os1("hll_sketch1.bin");
+        sketch1.serialize_compact(os1);
+    
+        // 100000 distinct keys
+        datasketches::hll_sketch sketch2(lg_k, type); // type is optional, defaults to HLL_4
+        for (int key = 50000; key < 150000; key++) sketch2.update(key);
+        std::ofstream os2("hll_sketch2.bin");
+        sketch2.serialize_compact(os2);
+      }
+    
+      // this section deserializes the sketches, produces union and prints the result
+      {
+        std::ifstream is1("hll_sketch1.bin");
+        datasketches::hll_sketch sketch1 = datasketches::hll_sketch::deserialize(is1);
+    
+        std::ifstream is2("hll_sketch2.bin");
+        datasketches::hll_sketch sketch2 = datasketches::hll_sketch::deserialize(is2);
+    
+        datasketches::hll_union u(lg_k);
+        u.update(sketch1);
+        u.update(sketch2);
+        datasketches::hll_sketch sketch = u.get_result(type); // type is optional, defaults to HLL_4
+    
+        // debug summary of the union result sketch
+        sketch.to_string(std::cout);
+    
+        std::cout << "Distinct count estimate: " << sketch.get_estimate() << std::endl;
+        std::cout << "Distinct count lower bound 95% confidence: " << sketch.get_lower_bound(2) << std::endl;
+        std::cout << "Distinct count upper bound 95% confidence: " << sketch.get_upper_bound(2) << std::endl;
+      }
+    
+      return 0;
+    }
+
+    ### HLL SKETCH SUMMARY: 
+      Log Config K   : 11
+      Hll Target     : HLL_4
+      Current Mode   : HLL
+      LB             : 148634
+      Estimate       : 152041
+      UB             : 155614
+      OutOfOrder flag: true
+      CurMin         : 4
+      NumAtCurMin    : 21
+      HipAccum       : 147291
+      KxQ0           : 19.889
+      KxQ1           : 0
+    Distinct count estimate: 152041
+    Distinct count lower bound 95% confidence: 145234
+    Distinct count upper bound 95% confidence: 159184


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