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pmttavara · Sep 25, 2018 · 618bf6f · 618bf6f
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-# pt_math
-public domain fast scalar math routines
+# pt_math.h
+This is a set of **branch-free, table-free** implementations of the math functions in `<math.h>`.
+
+All of the code is public domain - if you like, you can simply copy-paste the `sin` implementation if that's all you need.
+
+These functions differ slightly from the C standard library *by design* - **to stay fast, they don't do range checking or follow C's precision requirements.** Think of these routines more as "decent approximations", for when you know the particular input domain and you have leeway with the output. Video games are a good example of an appropriate use case.
+
+# API
+These functions stick to the C API, but it doesn't implement all of `math.h` - notable exclusions are machine-related functions (e.g. `fma`, `nextafter`), precision-related functions (e.g. `expm1`), complex numbers, and `tgamma`/`lgamma`. But you've got your standard elementary functions and hyperbolic trig as well.
+
+# Exceptions to branch-free rule
+`atan2` likely compiles to branches; it's hopelessly discontinuous.
+`dtoa` is a crappy implementation, included for completion.
+
+# Credits
+**There are no credits.** I want this library to be easy to use - which means public domain, and no attribution necessary.
+To be clear, I didn't invent all of these algorithms - but conveniently, the original authors are lost to time.
+The `sin` algorithm was originally conceived by an anonymous user on a now-unavailable programming forum, and the `log` algorithm is a