javascript static method
Math.f16round()
The Math.f16round() static method returns the nearest 16-bit half precision float representation of a number.
console.log(Math.f16round(5.5));
// Expected output: 5.5
console.log(Math.f16round(5.05));
// Expected output: 5.05078125
console.log(Math.f16round(5));
// Expected output: 5
console.log(Math.f16round(-5.05));
// Expected output: -5.05078125
Syntax
Math.f16round(doubleFloat)
Parameters
doubleFloat- : A number.
Return value
The nearest 16-bit half precision float representation of doubleFloat.
Description
Math.f16round is the 16-bit counterpart of fround(). It is intended to smooth some rough edges when interacting with float16 numbers, such as when reading from a Float16Array. Internally, JavaScript continues to treat the number as a 64-bit float, it just performs a “round to even” on the 10th bit of the mantissa, and sets all following mantissa bits to 0. If the number is outside the range of a 16-bit float, Infinity or -Infinity is returned.
Because f16round() is a static method of Math, you always use it as Math.f16round(), rather than as a method of a Math object you created (Math is not a constructor).
Examples
Using Math.f16round()
The number 1.5 can be precisely represented in the binary numeral system, and is identical in 16-bit and 64-bit:
Math.f16round(1.5); // 1.5
Math.f16round(1.5) === 1.5; // true
However, the number 1.337 cannot be precisely represented in the binary numeral system, so it differs in 16-bit and 64-bit:
Math.f16round(1.337); // 1.3369140625
Math.f16round(1.337) === 1.337; // false
100000 is too big for a 16-bit float, so Infinity is returned:
Math.f16round(100000); // Infinity