For the complete documentation index, see llms.txt. Markdown versions of all pages are available by appending .md to any URL (e.g. /get-started.md).
Mojo function
shuffle_up
def shuffle_up[dtype: DType, simd_width: SIMDLength, //](val: SIMD[dtype, simd_width], offset: UInt32) -> SIMD[dtype, simd_width]
Copies values from threads with lower lane IDs in the warp.
Performs a shuffle operation where each thread receives a value from a thread with a lower lane ID, offset by the specified amount. Uses the full warp mask by default.
For example, with offset=1:
- Thread N gets value from thread N-1
- Thread 1 gets value from thread 0
- Thread 0 gets undefined value
Parameters:
- dtype (
DType): The data type of the SIMD elements (e.g. float32, int32). - simd_width (
SIMDLength): The number of elements in each SIMD vector.
Args:
- val (
SIMD[dtype, simd_width]): The SIMD value to be shuffled up the warp. - offset (
UInt32): The number of lanes to shift values up by.
Returns:
SIMD[dtype, simd_width]: The SIMD value from the thread offset lanes lower in the warp.
Returns undefined values for threads where lane_id - offset < 0.
def shuffle_up[dtype: DType, simd_width: SIMDLength, //](mask: UInt, val: SIMD[dtype, simd_width], offset: UInt32) -> SIMD[dtype, simd_width]
Copies values from threads with lower lane IDs in the warp.
Performs a shuffle operation where each thread receives a value from a thread with a lower lane ID, offset by the specified amount. The operation is performed only for threads specified in the mask.
For example, with offset=1:
- Thread N gets value from thread N-1 if both threads are in the mask
- Thread 1 gets value from thread 0 if both threads are in the mask
- Thread 0 gets undefined value
- Threads not in the mask get undefined values
Parameters:
- dtype (
DType): The data type of the SIMD elements (e.g. float32, int32). - simd_width (
SIMDLength): The number of elements in each SIMD vector.
Args:
- mask (
UInt): The warp mask specifying which threads participate in the shuffle. - val (
SIMD[dtype, simd_width]): The SIMD value to be shuffled up the warp. - offset (
UInt32): The number of lanes to shift values up by.
Returns:
SIMD[dtype, simd_width]: The SIMD value from the thread offset lanes lower in the warp.
Returns undefined values for threads where lane_id - offset < 0 or
threads not in the mask.