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Update comments on double vs float

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See also #46
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Jason Turner
2015-12-30 13:30:38 -07:00
parent 571b39ca31
commit 1c2491c384
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08-Considering_Performance.md
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@@ -265,10 +265,13 @@ for (int i = 0; i < 15; ++i)
// obj is still taking up memory for no reason // obj is still taking up memory for no reason
``` ```
### Prefer `double` to `float` ### Prefer `double` to `float`, But Test First
Operations on `double`s are typically faster than `float`s. However, in vectorized operations, `float` might win out. Analyze the code and find out which is faster for your application! Depending on the situation and the compiler's ability to optimize, one may be faster over the other. Choosing `float` will result in lower precision and may be slower due to conversions. On vectorizable operations `float` may be faster if you are able to sacrifice precision.
`double` is the recomended default choice as it is the default type for floating point values in C++.
See this [stackoverflow](http://stackoverflow.com/questions/4584637/double-or-float-which-is-faster) discussion for some more information.
### Prefer `++i` to `i++` ### Prefer `++i` to `i++`
... when it is semantically correct. Pre-increment is [faster](http://blog2.emptycrate.com/content/why-i-faster-i-c) than post-increment because it does not require a copy of the object to be made. ... when it is semantically correct. Pre-increment is [faster](http://blog2.emptycrate.com/content/why-i-faster-i-c) than post-increment because it does not require a copy of the object to be made.