From: mail@...
Date: 2015-02-26T12:59:17+00:00
Subject: [ruby-core:68326] [Ruby trunk - Feature #10909] [PATCH 2/2] math.c: Direct casting from Rational to double.

Issue #10909 has been updated by gogo tanaka.


I can find this proposal makes `Math` faster more than 2 times at most.

    $ cat bench.rb

```ruby
require 'benchmark'

puts Benchmark.measure { 10000000.times { Math.cos 1          } }
puts Benchmark.measure { 10000000.times { Math.cos (1 << 100) } }
puts Benchmark.measure { 10000000.times { Math.cos 1.0        } }
puts Benchmark.measure { 10000000.times { Math.cos 1/3r       } }
puts Benchmark.measure { 10000000.times { Math.cos (1 << 100)/1r } }
```
### Before
```
  1.320000   0.010000   1.330000 (  1.326548)
  3.060000   0.000000   3.060000 (  3.064614)
  1.380000   0.000000   1.380000 (  1.383077)
  5.360000   0.010000   5.370000 (  5.435371)
 19.220000   0.050000  19.270000 ( 19.565904)
```
### After
```
  1.350000   0.000000   1.350000 (  1.357702)
  3.230000   0.010000   3.240000 (  3.247377)
  1.310000   0.000000   1.310000 (  1.315977)
  2.100000   0.000000   2.100000 (  2.106907)
 15.590000   0.040000  15.630000 ( 15.898346)
```

----------------------------------------
Feature #10909: [PATCH 2/2] math.c: Direct casting from Rational to double.
https://bugs.ruby-lang.org/issues/10909#change-51677

* Author: gogo tanaka
* Status: Open
* Priority: Normal
* Assignee: 
----------------------------------------
Hi, this proposal is continued from [Feature 10800](https://bugs.ruby-lang.org/issues/10800) and [Feature 10785](https://bugs.ruby-lang.org/issues/10785)
I'd like to do cast from Rational to double unless Rational#to_f is redefined.
Along with that, I've introduced some new macros(`fix2dbl_without_to_f`, `big2dbl_without_to_f`, ..) and added test cases.

Please feel free to let me know if there are something you don't like.

thanks.

---Files--------------------------------
direct_casting_from_Rational_to_double.patch (1.45 KB)
add_tests_to_test_math_rb.patch (1.79 KB)


-- 
https://bugs.ruby-lang.org/