FAST_NORMALIZE(3clc)

💖 FAST_NORMALIZE (3clc) 💖

okay bestie, buckle up — this one's from the OpenCL Manual, and it's literally the glow-up function for vectors. no cap.

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✨ NAME ✨

fast_normalize — Normal vector length 1.

floatn fast_normalize(floatn p);

like… it takes your vector and gives it main character energy at exactly length 1. 💅

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🦋 DESCRIPTION 🦋

So here's the tea: it hands you back a vector pointing in the same direction as p, but with a length of exactly 1. Slay.

fast_normalize</p> is computed as:

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

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

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

✨ but wait, there's exceptions, bestie, and you gotta know them:

1. If the sum of squares is greater than FLT_MAX then the value of the floating-point values in the result vector are undefined. 🫠 not a vibe.
2. If the sum of squares is less than FLT_MIN then the implementation may return back p.
3. If the device is in 'denorms are flushed to zero' mode, individual operand elements with magnitude less than sqrt(3clc)(FLT_MIN) may be flushed to zero before proceeding with the calculation. 😭

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🌸 NOTES 🌸

Built-in geometric functions operate component-wise. The description is per-component. floatn is float, float2, float3, or float4 and doublen 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). iconic behaviour honestly.

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👑 SPECIFICATION 👑

OpenCL Specification[1]

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🔥 SEE ALSO 🔥

• geometricFunctions(3clc) — go read this one too, iykyk 💜

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🌈 AUTHORS 🌈

The Khronos Group

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💖 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.

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⭐ NOTES ⭐

1. OpenCL Specification — page 262, section 6.12.5 - Geometric Functions

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🫶 that's the whole page, bestie — every flag, every number, every warning. no skips, no shortcuts, periodt.

The Khronos Group wrote this one, it's dated 01/14/2021, and it lives in the FAST_NORMALIZE(3clc) era of the OpenCL Manual. go normalize something cute today ✨💅🎀