jm + hyperloglog   12

jomsdev notes:

'Last year, in the AofA’16 conference Robert Sedgewick proposed a new algorithm for cardinality estimation. Robert Sedgwick is a professor at Princeton with a long track of publications on combinatorial/randomized algorithms. He was a good friend of Philippe Flajolet (creator of Hyperloglog) and HyperBitBit it's based on the same ideas. However, it uses less memory than Hyperloglog and can provide the same results. On practical data, HyperBitBit, for N < 2^64 estimates cardinality within 10% using only 128 + 6 bits.'
algorithms  programming  cs  hyperloglog  estimation  cardinality  counting  hyperbitbit 
5 weeks ago by jm
A probabilistic data structure for frequency/k-occurrence cardinality estimation of multisets. Sample implementation

(via Patrick McFadin)
via:patrickmcfadin  hyperloglog  cardinality  data-structures  algorithms  hyperlogsandwich  counting  estimation  lossy  multisets 
may 2015 by jm
HyperLogLog - Intersection Arithmetic
'In general HLL intersection in StreamLib works.  |A INTERSECT B|
= |A| + |B| - |A UNION B|.  Timon's article on intersection is
important to read though.  The usefulness of HLL intersection depends
on the features of the HLLs you are intersecting.'
hyperloglog  hll  hyperloglogplus  streamlib  intersections  sets  estimation  algorithms 
april 2014 by jm
Druid | How We Scaled HyperLogLog: Three Real-World Optimizations
3 optimizations have made to the HLL algorithm to scale it up for production use in Metamarkets: compacting registers (fixes a bug with unions of multiple HLLs); a sparse storage format (to optimize space); faster lookups using a lookup table.  metamarkets  scaling  hyperloglog  hll  algorithms  performance  optimization  counting  estimation 
april 2014 by jm
Philippe Flajolet’s contribution to streaming algorithms [preso]
Nice deck covering HyperLogLog and its origins, plus a slide at the end covering the Flajolet/Wegman Adaptive Sampling algorithm ("how do you count the number of elements which appear only once in stream using constant size memory?")
algorithms  sketching  hyperloglog  flajolet  wegman  adaptive-sampling  sampling  presentations  slides 
november 2013 by jm
Good UI for exploration of HyperLogLog set intersections and unions.
One of the first things that we wanted to do with HyperLogLog when we first started playing with it was to support and expose it natively in the browser. The thought of allowing users to directly interact with these structures -- perform arbitrary unions and intersections on effectively unbounded sets all on the client -- was exhilarating to us. [...] we are pleased to announce the open-source release of AK’s HyperLogLog implementation for JavaScript, js-hll. We are releasing this code under the Apache License, Version 2.0.

We knew that we couldn’t just release a bunch of JavaScript code without allowing you to see it in action — that would be a crime. We passed a few ideas around and the one that kept bubbling to the top was a way to kill two birds with one stone. We wanted something that would showcase what you can do with HLL in the browser and give us a tool for explaining HLLs. It is typical for us to explain how HLL intersections work using a Venn diagram. You draw some overlapping circles with a border that represents the error and you talk about how if that border is close to or larger than the intersection then you can’t say much about the size of that intersection. This works just ok on a whiteboard but what you really want is to just build a visualization that allows you to select from some sets and see the overlap. Maybe even play with the precision a little bit to see how that changes the result. Well, we did just that!
javascript  ui  hll  hyperloglog  algorithms  sketching  js  sets  intersection  union  apache  open-source 
june 2013 by jm
HyperLogLog++: Google’s Take On Engineering HLL
Google and AggregateKnowledge's improvements to the HyperLogLog cardinality estimation algorithm
hyperloglog  cardinality  estimation  streaming  stream-processing  cep 
february 2013 by jm
clearspring / stream-lib
ASL-licensed open source library of stream-processing/approximation algorithms: count-min sketch, space-saving top-k, cardinality estimation, LogLog, HyperLogLog, MurmurHash, lookup3 hash, Bloom filters, q-digest, stochastic top-k
algorithms  coding  streams  cep  stream-processing  approximation  probabilistic  space-saving  top-k  cardinality  estimation  bloom-filters  q-digest  loglog  hyperloglog  murmurhash  lookup3 
february 2013 by jm
aaw/hyperloglog-redis - GitHub
'This gem is a pure Ruby implementation of the HyperLogLog algorithm for estimating cardinalities of sets observed via a stream of events. A Redis instance is used for storing the counters.'
cardinality  sets  redis  algorithms  ruby  gems  hyperloglog 
january 2013 by jm

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