I'm sorry to see some of the math functions go.

A preview of my mathx library for 5.3 is availabe at
http://www.tecgraf.puc-rio.br/~lhf/ftp/lua/#lmathx
It also contains a Lua script for generating most of the binding
which may be useful for customization.
Here are the function mathx contains:
abs cosh fmod lgamma round
acos deg frexp log scalbn
acosh erf gamma log10 sin
asin erfc hypot log1p sinh
asinh exp isfinite log2 sqrt
atan exp2 isinf logb tan
atan2 expm1 isnan modf tanh
atanh fdim isnormal nearbyint trunc
cbrt floor j0 nextafter y0
ceil fma j1 pow y1
copysign fmax jn rad yn
cos fmin ldexp remainder
It includes the Bessel functions j0, j1, jn, y0, y1, yn, which I think are
Posix extensions. The script for generating the binding can be easiy
changed to skip these.
These are present in C99 but have been omitted because I think
they don't make much sense in Lua. Otherwise, please let me know.
remquo, nan(), ilogb, rint, lrint, lround, scalbln, signbit, fpclassify
These will probably be added in the final release:
fegetround, fesetround
Some function have been renamed to better names:
fabs -> abs
tgamma -> gamma
Perhaps these changes should be done as well:
atan2 -> atan (as in Lua 5.3)
fmin -> min
fmax -> max
log -> accept an optional base
Finally, like previous versions of mathx, this one adds functions the
existing math library, overwriting the functions already there. This
is a problem for abs (which works with integers as well) and log (which
accepts an optional base; this one is easy to fix).
All feedback welcome. Thanks.