Slug #1680
FloorLog2 or SizeInBase?
Description
In several places FloorLog2 is used to obtain a quick estimate of the
size of an integer; however, SizeInBase is noticeably faster (and just
as accurate, if the base is 2).
Check through the code, and replace FloorLog2 by SizeInBase where appropriate.
Related issues
History
#1
Updated by John Abbott about 2 years ago
Updated by I had completely forgotten that we had created SizeInBase.FloorLog2 is fairly quick, but SizeInBase is instant.
I do not really expect changing the calls to make a great speed
difference, but it is worth changing just for "cleanliness"
(and to remind me that SizeInBase is the quick size estimate fn).
#2
Updated by John Abbott almost 2 years ago
- Status changed from New to In Progress
- % Done changed from 0 to 10
Would it not be better to use the name BitSize rather than require that the user call SizeInBase(N,2)?
Would we even need to make SizeInBase public?
#3
Updated by John Abbott almost 2 years ago
Anna says that I should have impl'd FloorLog2 so that it calls SizeInBase directly.
Ooops. Why did I not think of that?
#4
Updated by John Abbott almost 2 years ago
- Status changed from In Progress to Feedback
- % Done changed from 10 to 90
Changed impl of FloorLog2 as described above... why was it not already like that? No idea!
All tests pass.
#5
Updated by John Abbott almost 2 years ago
SizeInBase is called only rarely; I have replaced one by a call to FloorLog2 because I think it makes the code clearer.
I shall remove the default value for arg 2 in SizeInBase since it makes no sense (to me now).
#6
Updated by John Abbott over 1 year ago
- Related to Design #1693: SizeInBase: obsolete added
#7
Updated by John Abbott over 1 year ago
- Status changed from Feedback to Closed
- % Done changed from 90 to 100
- Estimated time set to 1.66 h
After discussion with Anna we have decided that SizeInBase is obsolete; so the original question here is no longer relevant.
FloorLog2 has been made faster (both for BigInt and for machine ints).