[BACKEND] Handle scan of function non commutative (#2362)

Make sure we accumulate in the right order for scans so that non
commutative operations are handled correctly.
This commit is contained in:
Thomas Raoux
2023-09-21 12:00:41 -07:00
committed by GitHub
parent be9849bda9
commit e36c99b588
2 changed files with 47 additions and 25 deletions

View File

@@ -1716,10 +1716,16 @@ scan_configs = [
for type in ['int32', 'float32']
for axis in [1, 0]
for shape in scan2d_shapes
for op in ['cumsum', 'cumprod']
for op in ['cumsum', 'cumprod', 'get_first_element']
]
@triton.jit
# trivial associative but not commutative function
def get_first_element(a, b):
return a
@pytest.mark.parametrize("op, dtype_str, shape, axis, num_warps", scan_configs)
def test_scan2d(op, dtype_str, shape, axis, num_warps, device):
if is_hip():
@@ -1735,15 +1741,26 @@ def test_scan2d(op, dtype_str, shape, axis, num_warps, device):
z = GENERATE_TEST_HERE
tl.store(Z + range_m[:, None] * BLOCK_N + range_n[None, :], z)
kernel = patch_kernel(kernel, {'GENERATE_TEST_HERE': f'tl.{op}(x, axis={axis})'})
if op == 'cumsum' or op == 'cumprod':
kernel = patch_kernel(kernel, {'GENERATE_TEST_HERE': f'tl.{op}(x, axis={axis})'})
else:
kernel = patch_kernel(kernel, {'GENERATE_TEST_HERE': f'tl.associative_scan(x, axis={axis}, combine_fn={op})'})
# input
rs = RandomState(17)
x = numpy_random(shape, dtype_str=dtype_str, rs=rs)
z = np.empty_like(x)
x_tri = to_triton(x, device=device)
numpy_op = {'cumsum': np.cumsum, 'cumprod': np.cumprod}[op]
z_dtype_str = dtype_str
z_ref = numpy_op(x, axis=axis).astype(getattr(np, z_dtype_str))
if op == 'cumsum' or op == 'cumprod':
numpy_op = {'cumsum': np.cumsum, 'cumprod': np.cumprod}[op]
z_dtype_str = dtype_str
z_ref = numpy_op(x, axis=axis).astype(getattr(np, z_dtype_str))
else:
assert op == 'get_first_element'
z_ref = x
if axis == 0:
z_ref[1:] = x[0]
else:
z_ref[:, 1:] = x[:, 0:1]
# triton result
z_tri = to_triton(z, device=device)
kernel[(1,)](x_tri, z_tri, BLOCK_M=shape[0], BLOCK_N=shape[1], AXIS=axis, num_warps=num_warps)