Counting large numbers of events in small registers

  • Authors:
  • Robert Morris

  • Affiliations:
  • Bell Labs., Murray Hill, NJ

  • Venue:
  • Communications of the ACM
  • Year:
  • 1978

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Abstract

It is possible to use a small counter to keep approximate counts of large numbers. The resulting expected error can be rather precisely controlled. An example is given in which 8-bit counters (bytes) are used to keep track of as many as 130,000 events with a relative error which is substantially independent of the number n of events. This relative error can be expected to be 24 percent or less 95 percent of the time (i.e. &sgr; = n/8). The techniques could be used to advantage in multichannel counting hardware or software used for the monitoring of experiments or processes.