## table of contents

FAST_NORMALIZE(3clc) | OpenCL Manual | FAST_NORMALIZE(3clc) |

# NAME¶

fast_normalize - Normal vector length 1.

# ¶

**floatn
fast_normalize(floatn ***p***);**

# DESCRIPTION¶

Returns a vector in the same direction as *p* but with a
length of 1. **fast_normalize** is computed as:

p*sqrt(3clc)(p.x2 +p.y2 +...)

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

if (any(3clc)(p== 0.0f))result = p; elseresult = p/sqrt(3clc)(p.x2 +p.y2 +...);

with the following exceptions:

**FLT_MAX**then the value of the floating-point values in the result vector are undefined.

**FLT_MIN**then the implementation may return back

*p*.

**sqrt**(3clc)(

**FLT_MIN**) may be flushed to zero before proceeding with the calculation.

# NOTES¶

Built-in geometric functions operate component-wise. The
description is per-component. **float***n* is **float**,
**float2**, **float3**, or **float4** and
**double***n* is **double**, **double2**,
**double3**, or **double4**. 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**(3clc) or **fma**(3clc).

# SPECIFICATION¶

**OpenCL Specification**[1]

# SEE ALSO¶

**geometricFunctions**(3clc)

# AUTHORS¶

**The Khronos Group**

# COPYRIGHT¶

Copyright © 2007-2011 The Khronos Group Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction,
including without limitation the rights to use, copy, modify, merge,
publish, distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to the
condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials.

# NOTES¶

- 1.
- OpenCL Specification

01/14/2021 | The Khronos Group |