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Open problem: optimal calculator keyboard layout based on key usage statistics
05-28-2018, 01:27 PM (This post was last modified: 05-28-2018 10:29 PM by emece67.)
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Open problem: optimal calculator keyboard layout based on key usage statistics
Hi all,

Motivated by some discussions about the key layout of the, maybe, future wp43s, I decided to measure the relative usage frequencies of the keys in a calculator.

For that purpose, I modified the source code of the wp34s Qt emulator for it to keep a record, on disk, of the key usage. After a few days of not using any "real" machine, but only the emulator, I do have now some preliminary numbers. As I'm only interested in the basic layout of the machine (that is: number input plus basic ops, this translates to digits, decimal point, CHS, ENTER, EEX, 4 basic ops, backspace, SWAP, down stack & EXIT), I'll only show the numbers for such keys. They are (key: % usage)
  • 0: 9.77
  • 2: 8.35
  • 1: 8.24
  • ENTER: 6.97
  • .: 5.82
  • 5: 5.74
  • 3: 5.05
  • /: 4.26
  • 6: 4.23
  • 7: 3.73
  • 4: 3.71
  • 8: 3.04
  • Backspace/CLx: 2.89
  • *: 2.58
  • -: 2.09
  • +: 1.93
  • 9: 1.34
  • EXX: 0.97
  • CHS: 0.93
  • X<>Y: 0.91
  • EXIT: 0.86
  • Stack down: 0.16

Based upon this frequencies, what do you think will be an "optimal" keyboard layout, minimizing the finger flight time. Some rules to be obeyed:
  • The keys will be placed in a rectangular array
  • ENTER will occupy a double sized site
  • 1-9 will be placed in the usual way 1-2-3 below 4-5-6 below 7-8-9
  • +-*/ (in the order you decide) will be placed contiguous in a single column or row

Some other interesting data and open questions:
  • The % usage of the combined 3 shifts in the wp34s was 6.16%
  • There were aprox. 5 RCL for each STO
  • Do the digit key frequencies follow the Benford's law?
  • Do you think that, after all, there may be a reason after early hp machines having the ENTER and the basic operations at the left, with / at the bottom?

Thoughts and layout proposals?
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Open problem: optimal calculator keyboard layout based on key usage statistics - emece67 - 05-28-2018 01:27 PM



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