SIMD.js has been taken out of active development in TC39 and removed from Stage 3. It is not being pursued by web browsers for implementation anymore. SIMD operations exposed to the web are under active development within WebAssembly, with operations based on the SIMD.js operations.

The static SIMD.%type%.reciprocalSqrtApproximation() method returns a new instance with an approximation of the reciprocal value (1 / x) of the square root (Math.sqrt()) of the lane values.




An instance of a corresponding SIMD type.

Return value

A new corresponding SIMD data type with the reciprocal (1 / x) of the square root (Math.sqrt()) of the values.


The SIMD.%type%.reciprocalSqrtApproximation() is an approximation of the reciprocal of the square root of the lane values. This means that an estimation of the reciprocal of a number is calculated and that there can be a small amount of error. The Newton-Raphson division, for example, is one of the fast division methods that calculates an estimation. See also this ARM/NEON FAQ article.


var a = SIMD.Float32x4(1, 2, 3, 4);
// Float32x4[1, 0.7071067690849304, 0.5773502588272095, 0.5]

var b = SIMD.Float64x2(0, Infinity);
// Float64x2[Infinity, 0]


Specification Status Comment
The definition of 'SIMDConstructor.reciprocalSqrtApproximation' in that specification.
Obsolete Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support Nightly build No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support Nightly build No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: fscholz
 Last updated by: fscholz,