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Computer scientists invent an efficient new way to count (quantamagazine.org)

993 points by jasondavies · 820 days ago · 287 comments on HN

Article summary

Computer scientists have developed a new algorithm, called CVM, to efficiently estimate the number of distinct elements in a large list. The algorithm uses randomization to select a subset of elements, which can then be used to estimate the total number of unique elements. This approach is particularly useful when the list is too large to fit into memory. The CVM algorithm has been shown to be accurate and efficient, even with limited memory.

Main themes

  • Distinct Elements Problem
  • Algorithm Design
  • Randomization Techniques
  • Data Streaming
  • Estimation Algorithms
  • Computer Science Research

What commenters say

  • The CVM algorithm is similar to existing methods like HyperLogLog, but with a simpler and more efficient approach.
  • The algorithm's use of randomization allows for accurate estimation of distinct elements, even with limited memory.
  • Some commenters argue that the title of the article is misleading, as the algorithm is an estimation technique rather than an exact counting method.
  • The CVM algorithm has potential applications in data streaming and processing, where exact counting is not always necessary or feasible.
  • The technique of relying on probabilistic ranges rather than exact numbers can be a useful approach to solving complex problems.
  • The algorithm's accuracy scales with the size of the memory, making it a useful tool for estimating distinct elements in large datasets.
  • Some commenters note that the distinction between estimation and exact counting is not always significant, and that the algorithm's approach can be useful in practice.
  • The CVM algorithm's simplicity and efficiency make it a promising solution for a range of problems in computer science and data analysis.