Replace _reduce_3_tuple with math.prod in _launcher.pyx

Remove the now-dead _reduce_3_tuple helper from cuda_utils.pyx.

Made-with: Cursor

Author: Andy-Jost

cuda_core/cuda/core/_launcher.pyx

@@ -17,7 +17,7 @@ from cuda.core._utils.cuda_utils cimport (
 )
 from cuda.core._module import Kernel
 from cuda.core._stream import Stream
-from cuda.core._utils.cuda_utils import _reduce_3_tuple
+from math import prod
 
 
 def launch(stream: Stream | GraphBuilder | IsStreamT, config: LaunchConfig, kernel: Kernel, *kernel_args):
@@ -62,9 +62,9 @@ cdef _check_cooperative_launch(kernel: Kernel, config: LaunchConfig, stream: Str
     dev = stream.device
     num_sm = dev.properties.multiprocessor_count
     max_grid_size = (
-        kernel.occupancy.max_active_blocks_per_multiprocessor(_reduce_3_tuple(config.block), config.shmem_size) * num_sm
+        kernel.occupancy.max_active_blocks_per_multiprocessor(prod(config.block), config.shmem_size) * num_sm
     )
-    if _reduce_3_tuple(config.grid) > max_grid_size:
+    if prod(config.grid) > max_grid_size:
         # For now let's try not to be smart and adjust the grid size behind users' back.
         # We explicitly ask users to adjust.
         x, y, z = config.grid

cuda_core/cuda/core/_utils/cuda_utils.pyx

@@ -60,10 +60,6 @@ def cast_to_3_tuple(label, cfg):
     return cfg + (1,) * (3 - len(cfg))
 
 
-def _reduce_3_tuple(t: tuple):
-    return t[0] * t[1] * t[2]
-
-
 cdef int HANDLE_RETURN(cydriver.CUresult err) except?-1 nogil:
     if err != cydriver.CUresult.CUDA_SUCCESS:
         return _check_driver_error(err)