yeahrb/yeah — pull request #25 by meganemura (2014-08-23 03:47:44+00:00)
Title: Simplify unary negation operator

this commit improves `-@` method.
it is forgotten in b48445786966e75c53c13afd258f852fa78ba56d.

Benchmark(#24) results are as follows.
```sh
$ rake benchmark:vector
user system total real
+ 0.080000 0.000000 0.080000 ( 0.079335)
- 0.080000 0.000000 0.080000 ( 0.072993)
* 0.070000 0.000000 0.070000 ( 0.069291)
/ 0.070000 0.000000 0.070000 ( 0.071865)
+@ 0.060000 0.000000 0.060000 ( 0.068067)
-@ 0.080000 0.000000 0.080000 ( 0.072928) # <-
length 0.050000 0.000000 0.050000 ( 0.052774)
distance_to 0.110000 0.000000 0.110000 ( 0.111375)
angle_to 0.160000 0.000000 0.160000 ( 0.156575)
along 0.110000 0.000000 0.110000 ( 0.111847)
along! 0.060000 0.000000 0.060000 ( 0.068772)
```