You can use "measure" command to check performance in IRB like below:
irb(main):001:0> 3
=> 3
irb(main):002:0> measure
TIME is added.
=> nil
irb(main):003:0> 3
processing time: 0.000058s
=> 3
irb(main):004:0> measure :off
=> nil
irb(main):005:0> 3
=> 3
You can set "measure :on" by "IRB.conf[:MEASURE] = true" in .irbrc, and, also,
set custom performance check method:
IRB.conf[:MEASURE_PROC][:CUSTOM] = proc { |context, code, line_no, &block|
time = Time.now
result = block.()
now = Time.now
puts 'custom processing time: %fs' % (Time.now - time) if IRB.conf[:MEASURE]
result
}
https://github.com/ruby/irb/commit/3899eaf2e2
This new mode uses a copy of the TOPLEVEL_BINDING. This is compatible with refinements (contrary to mode 3), while keeping nested IRB sessions separate
https://github.com/ruby/irb/commit/25c731cb2f
Miller Rabin algorithm can be used to test primality for integers smaller than a max value "MaxMR" (~3e24)
It can be much faster than previous implementation: ~100x faster for numbers with 13 digits, at least 5 orders of magnitude for even larger numbers (previous implementation is so slow that it requires more patience than I have for more precise estimate).
Miller Rabin test becomes faster than previous implementation at somewhere in the range 1e5-1e6. It seems that the range 62000..66000 is where Miller Rabin starts being always faster, so I picked 0xffff arbitrarily; before that, or above "MaxMR", the previous implementation remains.
I compared the `faster_prime` gem too. It is slower than previous implementation up to ~1e4. After that it becomes faster and faster compared to previous implementation, but is still slower than Miller Rabin starting at ~1e5 and up to MaxMR. Thus, after this commit, builtin `Integer#prime?` will be similar or faster than `faster_prime` up to "MaxMR".
Adapted from patch of Stephen Blackstone [Feature #16468]
Benchmark results and code: https://gist.github.com/marcandre/b263bdae488e76dabdda84daf73733b9
Co-authored-by: Stephen Blackstone <sblackstone@gmail.com>
Avoiding recursive call would imply iterating bits starting from
most significant, which is not easy to do efficiently.
Any saving would be dwarfed by the multiplications anyways.
[Feature #15233]
When running irb 1.2.1 (2019-12-24) with frozen-string-literal enabled, it crashes in reline with `can't modify frozen String (FrozenError)`
Steps to reproduce:
`RUBYOPT="--enable-frozen-string-literal" irb`
