Math.f16round()
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
The Math.f16round()
static method returns the nearest 16-bit half precision float representation of a number.
Try it
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 Math.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
Specifications
Specification |
---|
Float16Array # sec-math.f16round |
Browser compatibility
BCD tables only load in the browser