ILOGB(3clc)

✨ ilogb — bestie's guide to the exponent ✨

okay so you're in the OpenCL Manual and you clicked on ILOGB(3clc), which is literally the glow-up for your exponent math. let's get into it 💅

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💖 NAME 💖

ilogb — exponent as an integer value. that's it. that's the whole vibe. it takes your float and hands you back the exponent, but as an int instead of a float. periodt.

here's the full squad of signatures, and yes, every single one of them is valid:

intn ilogb(floatn x);

int ilogb(float x);

intn ilogb(doublen x);

int ilogb(double x);

intn ilogb(halfn x);

int ilogb(half x);

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🌸 DESCRIPTION 🌸

Returns the exponent as an integer value. iconic. no cap.

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🦋 NOTES 🦋

okay bestie, this is the part where the important lore lives, so pay attention 🫶

• The vector versions of the math functions operate component-wise. The description is per-component. so like, each lil lane does its own thing, independently.
• The built-in math functions are not affected by the prevailing rounding mode in the calling environment, and always return the same value as they would if called with the round to nearest even rounding mode. so your env can't come in and start drama, fr fr.
• The built-in math functions take scalar or vector arguments. For any specific use of these function, the actual type has to be the same for all arguments and the return type unless otherwise specified. matching types only, bestie, we don't mix.
• The generic type name gentype is used to indicate that the function can take float, float2, float3, float4, float8, float16, double, double2, double3, double4, double8, or double16 as the type for the arguments.
• If extended with cl_khr_fp16(3clc), generic type name gentype may indicate half and half{2|3|4|8|16} as arguments and return values. half squad, rise 🧚
• The generic type name gentypef is used to indicate that the function can take float, float2, float3, float4, float8, or float16 as the type for the arguments.
• The generic type name gentyped is used to indicate that the function can take double, double2, double3, double4, double8, or double16 as the type for the arguments.
• The following macros shall expand to integer constant expressions whose values are returned by ilogb(x) if x is zero or NaN, respectively. The value of FP_ILOGB0 shall be either {INT_MIN} or - {INT_MAX}. The value of FP_ILOGBNAN shall be either {INT_MAX} or {INT_MIN}.

⚠️ heads up on those macros — FP_ILOGB0 and FP_ILOGBNAN each have two legal values, so don't go assuming which one you'll get. that's the spec being the spec. 💀

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⭐ SPECIFICATION ⭐

OpenCL Specification[1]

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🌈 SEE ALSO 🌈

• mathFunctions(3clc)

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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 244, section 6.12.2 - Math Functions

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and that's the whole page, bestie 🫶 this lil gem is brought to you by The Khronos Group, dated 01/14/2021, filed under ILOGB(3clc) in the OpenCL Manual. go forth and compute those exponents, you absolute main character 💖✨