Symbolic Math Constants

The following symbolic constants are available.

Built-in Math Constants

The following symbolic constants are available. Their values are of type float and are accurate within the precision of a single precision floating-point number.

Constant Name Description
MAXFLOAT Value of maximum non-infinite single-precision floating-point number.
HUGE_VALF A positive float constant expression. HUGE_VALF evaluates to +infinity. Used as an error value returned by the built-in math functions.
INFINITY A constant expression of type float representing positive or unsigned infinity.
NAN A constant expression of type float representing a quiet NaN.

If double precision is supported by the device, the following symbolic constant will also be available:

Constant Name Description
HUGE_VAL

A positive double constant expression. HUGE_VAL evaluates to +infinity. Used as an error value returned by the built-in math functions.

The following constants are also available. They are of type float and are accurate within the precision of the float type.

Constant Name Description
M_E_F Value of e
M_LOG2E_F Value of log2e
M_LOG10E_F Value of log10e
M_LN2_F Value of loge2
M_LN10_F Value of loge10
M_PI_F Value of pi
M_PI_2_F Value of pi / 2
M_PI_4_F Value of pi / 4
M_1_PI_F Value of 1 / pi
M_2_PI_F Value of 2 / pi
M_2_SQRTPI_F Value of 2 / (square root of pi)
M_SQRT2_F Value of square root of 2
M_SQRT1_2_F Value of 1 / (square root of 2)

If double precision is supported by the device, the following macros and constants are also available. They are of type double and are accurate within the precision of the double type.

Constant Name Description
M_E Value of e
M_LOG2E Value of log2e
M_LOG10E Value of log10e
M_LN2 Value of loge2
M_LN10 Value of loge10
M_PI Value of pi
M_PI_2 Value of pi / 2
M_PI_4 Value of pi / 4
M_1_PI Value of 1 / pi
M_2_PI Value of 2 / pi
M_2_SQRTPI Value of 2 / (square root of pi)
M_SQRT2 Value of square root of 2
M_SQRT1_2 Value of 1 / (square root of 2)

The following constants are also available. They are of type half and are accurate within the precision of the half type. An application that wants to use half and halfn types will need to include the #pragma OPENCL EXTENSION cl_khr_fp16 : enable directive.

Constant Description
M_E_H Value of e
M_LOG2E_H Value of log2e
M_LOG10E_H Value of log10e
M_LN2_H Value of loge2
M_LN10_H Value of loge10
M_PI_H Value of pi
M_PI_2_H Value of pi / 2
M_PI_4_H Value of pi / 4
M_1_PI_H Value of 1 / pi
M_2_PI_H Value of 2 / pi
M_2_SQRTPI_H Value of 2 / (square root of pi)
M_SQRT2_H Value of square root of 2
M_SQRT1_2_H Value of 1 / (square root of 2)

Specification

OpenCL Specification

Also see

Math Functions, Floating Point Pragma, Macros and Limits

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.