Vector types and variables built in CUDA

CUDA The built-in Vector Types and variables

Built-in Vector Types

char, short, int, long, longlong, float, double

These are vector types derived from basic integer and floating-point types . They are structures , first 、 the second 、 The third and fourth components can be passed through fields x、y、z and w visit . They all carry make_<type name> Constructor of form ; for example ,

int2 make_int2(int x, int y);

It creates a with value(x, y) Of int2 Vector of type .
The alignment requirements of vector types are detailed in the following table .

Type	Alignment
char1, uchar1	1
char2, uchar2	2
char3, uchar3	1
char4, uchar4	4
short1, ushort1	2
short2, ushort2	4
short3, ushort3	2
short4, ushort4	8
int1, uint1	4
int2, uint2	8
int3, uint3	4
int4, uint4	16
long1, ulong1	4 if sizeof(long) is equal to sizeof(int) 8, otherwise
long2, ulong2	8 if sizeof(long) is equal to sizeof(int), 16, otherwise
long3, ulong3	4 if sizeof(long) is equal to sizeof(int), 8, otherwise
long4, ulong4	16
longlong1, ulonglong1	8
longlong2, ulonglong2	16
longlong3, ulonglong3	8
longlong4, ulonglong4	16
float1	4
float2	8
float3	4
float4	16
double1	8
double2	16
double3	8
double4	16

dim3

This type is based on uint3 Integer vector type of , Used to specify the dimension . Definition dim3 When a variable of type , Any unspecified components will be initialized to 1.

Built-in Variables

1. gridDim

The type of the variable is dim3（ see also dim3） And include the size of the grid .

2. blockIdx

The variable is uint3 type （ Please see the char、short、int、long、longlong、float、double） And include the block index in the grid .

3. blockDim

The type of the variable is dim3（ see also dim3） And include the size of the block .

4. threadIdx

This variable is uint3 type （ Please see the char、short、int、long、longlong、float、double ） And include the thread index in the block .

5. warpSize

The variable is int type , Contains warp size （ of warp The definition of , Please see the SIMT Architecture）.