AlexanderSaydakov commented on code in PR #325:
URL: https://github.com/apache/datasketches-cpp/pull/325#discussion_r1081688920
##########
count/include/count_min.hpp:
##########
@@ -0,0 +1,189 @@
+#ifndef COUNT_MIN_HPP_
+#define COUNT_MIN_HPP_
+
+#include <iterator>
+#include "common_defs.hpp"
+
+namespace datasketches {
+
+ /*
+ * C++ implementation of the CountMin sketch data structure of Cormode and
Muthukrishnan.
+ * [1] - http://dimacs.rutgers.edu/~graham/pubs/papers/cm-full.pdf
+ * The template type W is the type of the vector that contains the weights
of the objects inserted into the sketch,
+ * not the type of the input items themselves.
+ * @author Charlie Dickens
+ */
+
+template<typename W>
+class count_min_sketch{
+ static_assert(std::is_arithmetic<W>::value, "Arithmetic type expected");
+public:
+
+ /**
+ * Creates an instance of the sketch given parameters num_hashes, num_buckets
and hash seed, `seed`.
+ * @param num_hashes : number of hash functions in the sketch. Equivalently
the number of rows in the array
+ * @param num_buckets : number of buckets that hash functions map into.
Equivalently the number of columns in the array
+ * @param seed for hash function
+ *
+ * The items inserted into the sketch can be arbitrary type, so long as they
are hashable via murmurhash.
+ * Only update and estimate methods are added for uint64_t and string types.
+ */
+ count_min_sketch(uint16_t num_hashes, uint32_t num_buckets, uint64_t seed =
DEFAULT_SEED) ;
+
+ /**
+ * @return configured num_hashes of this sketch
+ */
+ uint16_t get_num_hashes() const;
+
+ /**
+ * @return configured num_buckets of this sketch
+ */
+ uint32_t get_num_buckets() const;
+
+ /**
+ * @return configured seed of this sketch
+ */
+ uint64_t get_seed() const;
+
+ /**
+ * @return epsilon : double
+ * The maximum permissible error for any frequency estimate query.
+ * epsilon = ceil(e / num_buckets)
+ */
+ double get_relative_error() ;
Review Comment:
this method should be const
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