From: michaelvasin@... Date: 2018-05-02T08:16:19+00:00 Subject: [ruby-core:86828] [Ruby trunk Bug#10212] MRI is not for lambda calculus Issue #10212 has been updated by mvasin (Mikhail Vasin). This code ``` def fib(x) return x if x == 0 || x == 1 fib(x-1) + fib(x-2) end t = Time.now; fib(40); puts Time.now - t ``` Runs 13,36 seconds on my machine. So lambda is 3 times slower. Does it have to be that slower? Ruby is manifested as a multi-paradigm language, but recursion and lambdas are way too slow to actually use it in a functional style... ---------------------------------------- Bug #10212: MRI is not for lambda calculus https://bugs.ruby-lang.org/issues/10212#change-71790 * Author: ko1 (Koichi Sasada) * Status: Closed * Priority: Normal * Assignee: ko1 (Koichi Sasada) * Target version: * ruby -v: ruby 2.2.0dev (2014-08-21 trunk 47241) [x86_64-linux] * Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN ---------------------------------------- # title is joke. I added benchmark/bm_lc_fizzbuzz.rb which solve fizz buzz program by lambda calculus. http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=47447 (This program is closly described by ["Understanding Computation"] (http://computationbook.com/) by Tom Stuart) ([Japanese translation of this book] (http://www.oreilly.co.jp/books/9784873116976/) will be published soon) The results of this program are: ``` jruby 1.7.12 (1.9.3p392) 2014-04-15 643e292 on OpenJDK 64-Bit Server VM 1.7.0_65-b32 [linux-amd64] real 0m26.648s user 0m30.091s sys 0m4.369s mruby 89e9df26819b9555fb790a16662f4ad2b9cbb2e2 real 0m27.145s user 0m27.110s sys 0m0.012s ruby 2.2.0dev (2014-08-21 trunk 47241) [x86_64-linux] real 1m54.648s user 1m54.512s sys 0m0.028s ``` It is clear that MRI is too slow. I haven't dig details, but maybe it is because of GC perforamance. Because Proc (and Env) objects are wb-unprotected, such objects are marked on every minor GC. This problem is not critical because MRI is not for lambda calculus :p but we can improve about it. -- https://bugs.ruby-lang.org/ Unsubscribe: