# fast_normalize

Normal vector length 1.

## Description

Returns a vector in the same direction as `p`

but with a length of 1. `fast_normalize`

is computed as:

The result shall be within 8192 ulps error from the infinitely precise result of:

if ( all(`p`

== 0.0f))

`result = p`

;

else

`result = p`

/ sqrt(`p.x`

^{2} + `p.y`

^{2} +...);

with the following exceptions:

- If the sum of squares is greater than FLT_MAX then the value of the floating-point values in the result vector are undefined.
- If the sum of squares is less than FLT_MIN then the implementation may return back
`p`

.
- If the device is in 'denorms are flushed to zero' mode, individual operand elements with magnitude less than sqrt(FLT_MIN) may be flushed to zero before proceeding with the calculation.

## Notes

Built-in geometric functions operate component-wise and the description is per-component.
The type name float`n`

indicates that the function can take float,
float2, float3, or float4 as the type
for the arguments.

The built-in geometric functions are implemented using the round to nearest even rounding mode.

The geometric functions can be implemented using contractions such as
mad or
fma.

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