Scroll to navigation

SELECT(3clc) OpenCL Manual SELECT(3clc)


select - For each component of a vector type, result[i] = if MSB of c[i] is set ? b[i] : a[i]. For scalar type, result = c ? b : a.

gentype select(gentype a, gentype b, igentype c);

gentype select(gentype a, gentype b, ugentype c);

halfn select (halfn a, halfn b, shortn c) // if half extension enabled halfn select (halfn a, halfn b, ushortn c) // if half extension enabled


For each component of a vector type, result[i] = if MSB of c[i] is set ? b[i] : a[i].

For scalar type, result = c ? b : a.

igentype and ugentype must have the same number of elements and bits as gentype.


The argment type gentype can be char, charn,uchar, ucharn, short, shortn, ushort, ushortn, int, intn, uint, uintn, long, longn, ulong, ulongn, float, floatn, double, and doublen.

The argument type igentype refers to signed integer types, i.e. char, charn, short, shortn, int, intn, long, and longn.

The argument type ugentype refers to unsigned integer types, i.e. uchar, ucharn, ushort, ushortn, uint, uintn, ulong, and ulongn. n is 2, 3, 4, 8, or 16.

If an implementation extends this specification to support IEEE-754 flags or exceptions, then all built-in relational functions shall proceed without raising the invalid floating-point exception when one or more of the operands are NaNs.

The built-in relational functions are extended with cl_khr_fp16(3clc) to include appropriate versions of functions that take half, and half{2|3|4|8|16} as arguments and return values.


OpenCL Specification[1]




The Khronos Group


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.


OpenCL Specification
page 264, section 6.12.6 - Relational Functions
01/14/2021 The Khronos Group