3. Bfloat16 Precision Intrinsics

This section describes nv_bfloat16 precision intrinsic functions.

To use these functions, include the header file cuda_bf16.h in your program. All of the functions defined here are available in device code. Some of the functions are also available to host compilers, please refer to respective functions’ documentation for details.

NOTE: Aggressive floating-point optimizations performed by host or device compilers may affect numeric behavior of the functions implemented in this header. Specific examples are:

• hsin(__nv_bfloat16);

• hcos(__nv_bfloat16);

• h2sin(__nv_bfloat162);

• h2cos(__nv_bfloat162);

The following macros are available to help users selectively enable/disable various definitions present in the header file:

• CUDA_NO_BFLOAT16 - If defined, this macro will prevent the definition of additional type aliases in the global namespace, helping to avoid potential conflicts with symbols defined in the user program.

• __CUDA_NO_BFLOAT16_CONVERSIONS__ - If defined, this macro will prevent the use of the C++ type conversions (converting constructors and conversion operators) that are common for built-in floating-point types, but may be undesirable for __nv_bfloat16 which is essentially a user-defined type.

• __CUDA_NO_BFLOAT16_OPERATORS__ and __CUDA_NO_BFLOAT162_OPERATORS__ - If defined, these macros will prevent the inadvertent use of usual arithmetic and comparison operators. This enforces the storage-only type semantics and prevents C++ style computations on __nv_bfloat16 and __nv_bfloat162 types.

Groups

Bfloat16 Arithmetic Constants

To use these constants, include the header file cuda_bf16.h in your program.

Bfloat16 Arithmetic Functions

To use these functions, include the header file cuda_bf16.h in your program.

Bfloat16 Comparison Functions

To use these functions, include the header file cuda_bf16.h in your program.

Bfloat16 Math Functions

To use these functions, include the header file cuda_bf16.h in your program.

Bfloat16 Precision Conversion and Data Movement

To use these functions, include the header file cuda_bf16.h in your program.

Bfloat162 Arithmetic Functions

To use these functions, include the header file cuda_bf16.h in your program.

Bfloat162 Comparison Functions

To use these functions, include the header file cuda_bf16.h in your program.

Bfloat162 Math Functions

To use these functions, include the header file cuda_bf16.h in your program.

Structs

__nv_bfloat16

nv_bfloat16 datatype

__nv_bfloat162

nv_bfloat162 datatype

__nv_bfloat162_raw

__nv_bfloat162_raw data type

__nv_bfloat16_raw

__nv_bfloat16_raw data type

Typedefs

nv_bfloat16

This datatype is meant to be the first-class or fundamental implementation of the bfloat16 numbers format.

nv_bfloat162

This datatype is meant to be the first-class or fundamental implementation of type for pairs of bfloat16 numbers.

3.9. Typedefs

typedef __nv_bfloat16 nv_bfloat16

This datatype is meant to be the first-class or fundamental implementation of the bfloat16 numbers format.

Should be implemented in the compiler in the future. Current implementation is a simple typedef to a respective user-level type with underscores.

typedef __nv_bfloat162 nv_bfloat162

This datatype is meant to be the first-class or fundamental implementation of type for pairs of bfloat16 numbers.

Should be implemented in the compiler in the future. Current implementation is a simple typedef to a respective user-level type with underscores.