# Math

Mathematical operations as known from JavaScript.

The Math API is very much like JavaScript's (MDN (opens new window)), with the notable exceptions stated above and rest parameters not being supported yet.

# Variants

Math in AssemblyScript is available in multiple variants.

Variant	Description
NativeMath	WebAssembly implementation for `f64`
NativeMathf	WebAssembly implementation for `f32`
JSMath	JavaScript implementation for `f64` (imported from the host)

By default, the global Math object is an alias of NativeMath and Mathf is an alias of NativeMathf .

# Using JSMath

By default, the compiler utilizes NativeMath which is implemented in WebAssembly directly, but where small module size is more important than performance, one can opt to override the default by adding --use Math=JSMath on the command line, essentially aliasing Math with JSMath instead, which maps to an import of the browser's math implementation. Naturally, this option requires importing the browser's Math object as a whole, but does not require seeding / is not seedable. Generated bindings automatically take care of importing the browser's math in this scenario.

# Static members

The type T below substitutes either f32 or f64 depending on the implementation used. Note that Math is not actually generic, but concrete implementations like Math and Mathf have an identical interface that only differs in the implementation's floating-point precision denoted by T.

# Constants

```
const E: T
```
The base of natural logarithms, e, approximately 2.718.
```
const LN2: T
```
The natural logarithm of 2, approximately 0.693.
```
const LN10: T
```
The natural logarithm of 10, approximately 2.302.
```
const LOG2E: T
```
The base 2 logarithm of e, approximately 1.442.
```
const LOG10E: T
```
The base 10 logarithm of e, approximately 0.434.
```
const PI: T
```
The ratio of the circumference of a circle to its diameter, approximately 3.14159.
```
const SQRT1_2: T
```
The square root of 1/2, approximately 0.707.
```
const SQRT2: T
```
The square root of 2, approximately 1.414.

# Functions

```
function abs(x: T): T
```
Returns the absolute value of x.
```
function acos(x: T): T
```
Returns the arccosine (in radians) of x.
```
function acosh(x: T): T
```
Returns the hyperbolic arc-cosine of x.
```
function asin(x: T): T
```
Returns the arcsine (in radians) of x.
```
function asinh(x: T): T
```
Returns the hyperbolic arcsine of x.
```
function atan(x: T): T
```
Returns the arctangent (in radians) of x.
```
function atan2(y: T, x: T): T
```
Returns the arctangent of the quotient of its arguments.
```
function atanh(x: T): T
```
Returns the hyperbolic arctangent of x.
```
function cbrt(x: T): T
```
Returns the cube root of x.
```
function ceil(x: T): T
```
Returns the smallest integer greater than or equal to x.
```
function clz32(x: T): T
```
Returns the number of leading zero bits in the 32-bit binary representation of x.
```
function cos(x: T): T
```
Returns the cosine (in radians) of x.
```
function cosh(x: T): T
```
Returns the hyperbolic cosine of x.
```
function exp(x: T): T
```
Returns e to the power of x.
```
function expm1(x: T): T
```
Returns e to the power of x, minus 1.
```
function floor(x: T): T
```
Returns the largest integer less than or equal to x.
```
function fround(x: T): T
```
Returns the nearest 32-bit single precision float representation of x.
```
function hypot(value1: T, value2: T): T
```
Returns the square root of the sum of squares of its arguments.
```
function imul(a: T, b: T): T
```
Returns the result of the C-like 32-bit multiplication of a and b.
```
function log(x: T): T
```
Returns the natural logarithm (base e) of x.
```
function log10(x: T): T
```
Returns the base 10 logarithm of x.
```
function log1p(x: T): T
```
Returns the natural logarithm (base e) of 1 + x.
```
function log2(x: T): T
```
Returns the base 2 logarithm of x.
```
function max(value1: T, value2: T): T
```
Returns the largest-valued number of its arguments.
```
function min(value1: T, value2: T): T
```
Returns the lowest-valued number of its arguments.
```
function pow(base: T, exponent: T): T
```
Returns base to the power of exponent.
```
function random(): T
```
Returns a pseudo-random number in the range from 0.0 inclusive up to but not including 1.0.

Note that Math.random needs a way to seed the random number generator, which is achieved with a special import env.seed returning the seed as an f64 value. Generated bindings and WASI take care of it automatically.
```
function round(x: T): T
```
Returns the value of x rounded to the nearest integer.
```
function seedRandom(value: i64): void
```
Seeds the random function. Called internally by random if the seed hasn't been set.
```
function sign(x: T): T
```
Returns the sign of x, indicating whether the number is positive, negative or zero.
```
function signbit(x: T): bool
```
Returns whether the sign bit of x is set.
```
function sin(x: T): T
```
Returns the sine of x.
```
function sinh(x: T): T
```
Returns the hyperbolic sine of x.
```
function sqrt(x: T): T
```
Returns the square root of x.
```
function tan(x: T): T
```
Returns the tangent of x.
```
function tanh(x: T): T
```
Returns the hyperbolic tangent of x.
```
function trunc(x: T): T
```
Returns the integer part of x by removing any fractional digits.

# Considerations

The Math implementations are meant as a drop-in replacement for JavaScript's Math with all its quirks. For example, Math.round always rounds towards +Infinity and Math.imul and similar functions operate on number, which is f64 in AssemblyScript. Hence, using WebAssembly's math instructions directly where possible is often more efficient.

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