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RFC: Nim Math functions
Stock-take of Math functions
This is a comparison of math functions, with the aim of helping to identify if any functions are missing that may need to be added, etc. (in preparation for Nim V1.0)
Don't assume I correctly identified the Nim math functions (I may have missed some, or are available in other Nimble packages).
| Function | Nim | POSIX | old ISO | ISO C99 | Microsoft | Notes |
|---|---|---|---|---|---|---|
| acos | Y (arccos) | Y | Y | Y | Y | |
| acosh | Y (arccosh)\ | Y | N | Y | N | |
| asin | Y (arcsin) | Y | Y | Y | Y | |
| asinh | Y (arcsinh) | Y | N | Y | N | |
| atan | Y (arctan) | Y | Y | Y | Y | |
| atan2 | Y (arctan2) | Y | Y | Y | Y | |
| atanh | Y (arctanh) | Y | N | Y | N | |
| cbrt | Y | Y | N | Y | N | |
| ceil | Y | Y | Y | Y | Y | |
| copysign | N | Y | N | Y | Y | _copysign |
| cos | Y | Y | Y | Y | Y | |
| cosh | Y | Y | Y | Y | Y | |
| erf | Y | Y | N | Y | N | |
| erfc | Y | Y | N | Y | N | |
| exp | Y | Y | Y | Y | Y | |
| exp2 | N | Y | N | Y | N | |
| expm1 | N | Y | N | Y | N | |
| fabs | Y (abs) | Y | Y | Y | Y | |
| fdim | N | Y | N | Y | N | |
| floor | Y | Y | Y | Y | Y | |
| fma | N | Y | N | Y | N | |
| fmax | Y (max) | Y | N | Y | N | |
| fmin | Y (min) | Y | N | Y | N | |
| fmod | Y (mod) | Y | Y | Y | Y | |
| fpclassify | Y (classify) | Y | N | Y | Y | _fpclass |
| frexp | Y | Y | Y | Y | Y | |
| hypot | Y | Y | N | Y | Y | _hypot |
| ilogb | N | Y | N | Y | N | |
| isfinite | N | Y | N | Y | N | |
| isgreater | N | Y | N | Y | N | |
| isgreaterequal | N | Y | N | Y | N | |
| isinf | N | Y | N | Y | N | |
| isless | N | Y | N | Y | N | |
| islessequal | N | Y | N | Y | N | |
| islessgreater | N | Y | N | Y | N | |
| isnan | N | Y | N | Y | Y | _isnan |
| isnormal | N | Y | N | Y | N | |
| isunordered | N | Y | N | Y | N | |
| j0 | N | Y | N | N | Y | _j0 |
| j1 | N | Y | N | N | Y | _j1 |
| jn | N | Y | N | N | Y | _jn |
| ldexp | N | Y | Y | Y | Y | |
| lgamma | Y | Y | N | Y | N | |
| llrint | Y (round?) | Y | N | Y | N | |
| llround | N | Y | N | Y | N | |
| log | Y (ln) | Y | Y | Y | Y | |
| log10 | log10 | Y | Y | Y | Y | |
| log1p | Y | N | Y | N | ||
| log2 | Y | Y | N | Y | N | |
| logb | N | Y | N | Y | Y | _logb |
| lrint | Y (round) | Y | N | Y | N | |
| lround | N | Y | N | Y | N | |
| modf | Y (mod) | Y | Y | Y | Y | |
| nan | N (?) | Y | N | Y | N | |
| nearbyint | N | Y | N | Y | N | |
| nextafter | N | Y | N | Y | Y | _nextafter |
| nexttoward | N | N | N | Y | N | |
| pow | Y | Y | Y | Y | Y | |
| remainder | N (mod?) | Y | N | Y | N | |
| remquo | N | Y | N | Y | N | |
| rint | Y (round) | Y | N | Y | N | |
| round | N | Y | N | Y | N | |
| scalbln | N | Y | N | Y | N | |
| scalbn | N | N | N | Y | N | |
| signbit | N | Y | N | Y | N | |
| sin | Y | Y | Y | Y | Y | |
| sinh | Y | Y | Y | Y | Y | |
| sqrt | Y | Y | Y | Y | Y | |
| tan | Y | Y | Y | Y | Y | |
| tanh | Y | Y | Y | Y | Y | |
| tgamma | Y | Y | N | Y | N | |
| trunc | Y | Y | N | Y | N | |
| y0 | N | Y | N | N | Y | _y0 |
| y1 | N | Y | N | N | Y | _y1 |
| yn | N | Y | N | N | Y | _yn |
(the base table came from http://www.johndcook.com/blog/math_h/ )
links
- https://en.wikipedia.org/wiki/C_mathematical_functions
- http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf
I think it makes sense to include everything that is in ISO 99. Please create a PR to do so if you've got some time.
An equivalent to modf is now included in 46a2993917edd73fe55623a06999f4811067a754 (although it's called splitDecimal and returns the values as a tuple rather than passing a reference to an argument).
we should have a std/cmath.nim that is a pure low-level wrapper around importc procs.
Then std/math can import it but also work cross-backend with high-level portable wrappers that work in c,cpp,js,vm,nimscript backends.
EDIT: refs https://github.com/nim-lang/Nim/pull/16179#discussion_r535493710
Minor updated table:
| Function | Nim | POSIX | old ISO | ISO C99 | Microsoft | Notes |
|---|---|---|---|---|---|---|
| acos | Y (arccos) | Y | Y | Y | Y | |
| acosh | Y (arccosh)\ | Y | N | Y | N | |
| asin | Y (arcsin) | Y | Y | Y | Y | |
| asinh | Y (arcsinh) | Y | N | Y | N | |
| atan | Y (arctan) | Y | Y | Y | Y | |
| atan2 | Y (arctan2) | Y | Y | Y | Y | |
| atanh | Y (arctanh) | Y | N | Y | N | |
| cbrt | Y | Y | N | Y | N | |
| ceil | Y | Y | Y | Y | Y | |
| copysign | N | Y | N | Y | Y | _copysign |
| cos | Y | Y | Y | Y | Y | |
| cosh | Y | Y | Y | Y | Y | |
| erf | Y | Y | N | Y | N | |
| erfc | Y | Y | N | Y | N | |
| exp | Y | Y | Y | Y | Y | |
| exp2 | N | Y | N | Y | N | |
| expm1 | N | Y | N | Y | N | |
| fabs | Y (abs) | Y | Y | Y | Y | |
| fdim | N | Y | N | Y | N | |
| floor | Y | Y | Y | Y | Y | |
| fma | N | Y | N | Y | N | |
| fmax | Y (max) | Y | N | Y | N | |
| fmin | Y (min) | Y | N | Y | N | |
| fmod | Y (mod) | Y | Y | Y | Y | |
| fpclassify | Y (classify) | Y | N | Y | Y | _fpclass |
| frexp | Y | Y | Y | Y | Y | |
| hypot | Y | Y | N | Y | Y | _hypot |
| ilogb | N | Y | N | Y | N | |
| isfinite | N | Y | N | Y | N | |
| isgreater | N | Y | N | Y | N | |
| isgreaterequal | N | Y | N | Y | N | |
| isinf | N | Y | N | Y | N | |
| isless | N | Y | N | Y | N | |
| islessequal | N | Y | N | Y | N | |
| islessgreater | N | Y | N | Y | N | |
| isnan | N | Y | N | Y | Y | _isnan |
| isnormal | N | Y | N | Y | N | |
| isunordered | N | Y | N | Y | N | |
| j0 | N | Y | N | N | Y | _j0 |
| j1 | N | Y | N | N | Y | _j1 |
| jn | N | Y | N | N | Y | _jn |
| ldexp | N | Y | Y | Y | Y | |
| lgamma | Y | Y | N | Y | N | |
| llrint | Y (round?) | Y | N | Y | N | |
| llround | N | Y | N | Y | N | |
| log | Y (ln) | Y | Y | Y | Y | |
| log10 | log10 | Y | Y | Y | Y | |
| log1p | Y | N | Y | N | ||
| log2 | Y | Y | N | Y | N | |
| logb | N | Y | N | Y | Y | _logb |
| lrint | Y (round) | Y | N | Y | N | |
| lround | N | Y | N | Y | N | |
| modf | Y (mod) | Y | Y | Y | Y | |
| nan | N (?) | Y | N | Y | N | |
| nearbyint | N | Y | N | Y | N | |
| nextafter | N | Y | N | Y | Y | _nextafter |
| nexttoward | N | N | N | Y | N | |
| pow | Y | Y | Y | Y | Y | |
| remainder | N (mod?) | Y | N | Y | N | |
| remquo | N | Y | N | Y | N | |
| rint | Y (round) | Y | N | Y | N | |
| round | N | Y | N | Y | N | |
| scalbln | N | Y | N | Y | N | |
| scalbn | N | N | N | Y | N | |
| signbit | N | Y | N | Y | N | |
| sin | Y | Y | Y | Y | Y | |
| sinh | Y | Y | Y | Y | Y | |
| sqrt | Y | Y | Y | Y | Y | |
| tan | Y | Y | Y | Y | Y | |
| tanh | Y | Y | Y | Y | Y | |
| tgamma | Y | Y | N | Y | N | |
| trunc | Y | Y | N | Y | N | |
| y0 | N | Y | N | N | Y | _y0 |
| y1 | N | Y | N | N | Y | _y1 |
| yn | N | Y | N | N | Y | _yn |
- not everything in this list is equally valuable, we should focus on most common first (subjective, yes).
lrint | Y (round)
- we actually don't have
lrintand I wish we did;roundis different. maybe something like:
type RoundMode = enum rTowardsZero, ...
proc roundTo(x: SomeFloat, T: typedesc[SomeNumber], mode: static RoundMode): T
# or:
proc roundToInt(x: SomeFloat, mode: static RoundMode): int
which would map to one of the many lrint, lrintl, llrintl, round...