kalk

Kalk is a math parser library that supports user-defined variables and functions. An example of what it can parse:

``
f(x, y) = sum(1, 3, (2sin4/x!)^y) + cos(n deg)
a = 3
f(a, 2)
`
>> 1.1899401098014355

Features


Operators: +, -, , /, !
* Groups: (), [], ⌈ceil⌉, ⌊floor⌋
* Vectors: (x, y, z, ...)
* Matrices: [x, y, z; a, b, c; ...]
* Pre-defined functions and constants
* User-defined functions and variables. f(x, y) = xy, x = 5
* Root finding using Newton's method (eg. x^2 = 64). Note: estimation and limited to one root
* Derivative of functions (derivatives of noisy functions or of higher order can be a bit inaccurate). f'(2), sin'(-pi)
* Integration. ∫(0, pi, sin(x) dx) or ∫(0, π, sin(x) dx), maybe sometimes be slightly off
* Understands fairly ambiguous syntax. Eg. 2sin50 + 2xy
Sum function: sum(start, to, expression) Eg. sum(1, 3, 2n+1) is the same as 21+1 + 22+1 + 23+1 = 15
* Piecewise functions: f(x) = { f(x + 1) if x <= 1; x otherwise }, pressing enter before typing the final } will make a new line without submitting
* Different number bases: Either with a format like 0b1101, 0o5.3, 0xff or a format like 1101_2. The latter does not support letters, as they would be interpreted as variables
* Misc: separate expressions by a semicolon to write them on the same line, use the ans variable to get the value of the previously calculated expression

Rust Usage

`rust
use kalk::parser;
let mut parser_context = parser::Context::new();
let precision = 53;
let result = parser::eval(&mut parser_context, "5*3", precision).unwrap().unwrap();
assert_eq!(result.to_f64(), 15f64);
`

$3

The cargo feature rug enables rug, and is used by default. If you disable this, kalk will use f64 instead, making it more portable.

$3

Make sure you have diffutils gcc make and m4 installed.

JavaScript Usage

`js
const kalk = await import("@paddim8/kalk");
const context = new kalk.Context();
console.log(context.evaluate("2pi + 3").toScientificNotation().toString());
``