From 803a07263001e5466bba0f53fcc85784f4b5c686 Mon Sep 17 00:00:00 2001 From: Kouhei Yanagita Date: Fri, 22 Jul 2022 12:05:16 +0900 Subject: Improve performance of Integer#ceildiv This patch is suggested by nobu. Benchmark result: ``` require 'benchmark' n = 10 ** 7 Benchmark.bm do |x| x.report("Fixnum/Fixnum") { a, b = 5, 2; n.times { a.ceildiv(b) } } x.report("Bignum/Bignum") { a, b = 10**100, 10**99 - 1; n.times { a.ceildiv(b) } } x.report("Bignum/Fixnum") { a, b = 10**100, 3; n.times { a.ceildiv(b) } } end ``` Original: ``` user system total real Fixnum/Fixnum 3.340009 0.043029 3.383038 ( 3.384022) Bignum/Bignum 8.229500 0.118543 8.348043 ( 8.349574) Bignum/Fixnum 8.328971 0.097842 8.426813 ( 8.426952) ``` Improved: ``` user system total real Fixnum/Fixnum 0.699140 0.000961 0.700101 ( 0.700199) Bignum/Bignum 5.076165 0.083160 5.159325 ( 5.159360) Bignum/Fixnum 5.548684 0.115372 5.664056 ( 5.666735) ``` --- numeric.rb | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'numeric.rb') diff --git a/numeric.rb b/numeric.rb index 9f2200d2a8..c2091465f8 100644 --- a/numeric.rb +++ b/numeric.rb @@ -227,6 +227,23 @@ class Integer Primitive.attr! 'inline' Primitive.cexpr! 'rb_int_zero_p(self)' end + + # call-seq: + # ceildiv(other) -> integer + # + # Returns the result of division +self+ by +other+. The result is rounded up to the nearest integer. + # + # 3.ceildiv(3) # => 1 + # 4.ceildiv(3) # => 2 + # + # 4.ceildiv(-3) # => -1 + # -4.ceildiv(3) # => -1 + # -4.ceildiv(-3) # => 2 + # + # 3.ceildiv(1.2) # => 3 + def ceildiv(other) + -div(-other) + end end # call-seq: -- cgit v1.2.3