Suggest Count-Min sketch parameters

Helpers to translate a desired accuracy into the num_buckets and num_hashes arguments of count_min().

Usage

count_min_suggest_num_buckets(relative_error)

count_min_suggest_num_hashes(confidence)

Arguments

relative_error

Desired relative error, a single positive number. count_min_suggest_num_buckets() returns the smallest num_buckets such that the sketch's $relative_error() does not exceed this value.

confidence

Desired confidence, a single number in (0, 1]. count_min_suggest_num_hashes() returns the smallest num_hashes such that, with this probability, $estimate() is within $relative_error() of the true frequency.

Value

A single integer.

Examples

num_buckets <- count_min_suggest_num_buckets(0.05)
num_hashes <- count_min_suggest_num_hashes(0.95)
sketch <- count_min(num_hashes = num_hashes, num_buckets = num_buckets)