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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""
Shape broadcasting regression tests for RotaryEmbedding.forward_native.
Covers the batch-dimension shape mismatch fix: forward_native now strips the
batch dim from 3D cos/sin before applying RoPE, consistent with forward_cuda,
forward_hip, and apply_rotary_emb_mindiesd paths.
"""
from __future__ import annotations
import pytest
import torch
from vllm_omni.diffusion.layers.rope import RotaryEmbedding
pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
def _make_inputs(
batch: int,
seq_len: int,
num_heads: int,
head_dim: int,
cos_batch: int | None = None,
dtype: torch.dtype = torch.float32,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
"""Generate x, cos, sin tensors for RoPE testing.
Args:
batch: Batch dimension of x.
seq_len: Sequence length.
num_heads: Number of attention heads.
head_dim: Head dimension (must be even).
cos_batch: Batch dimension of cos/sin. Defaults to batch if None.
dtype: Data type for the tensors.
"""
if cos_batch is None:
cos_batch = batch
torch.manual_seed(42)
x = torch.randn(batch, seq_len, num_heads, head_dim, dtype=dtype)
cos = torch.randn(cos_batch, seq_len, head_dim // 2, dtype=dtype)
sin = torch.randn(cos_batch, seq_len, head_dim // 2, dtype=dtype)
return x, cos, sin
class TestRotaryEmbeddingNativeShapeRegression:
"""Regression tests for forward_native shape handling (#8e297d81)."""
@pytest.fixture
def rope_neox(self) -> RotaryEmbedding:
"""NeoX-style (non-interleaved) RoPE."""
return RotaryEmbedding(is_neox_style=True)
@pytest.fixture
def rope_gptj(self) -> RotaryEmbedding:
"""GPT-J style (interleaved) RoPE."""
return RotaryEmbedding(is_neox_style=False)
# ── 2D cos/sin (no batch dim) ──────────────────────────────────────
def test_2d_cos_sin_unchanged(self, rope_neox: RotaryEmbedding) -> None:
"""2D cos/sin [S, D/2] pass through unchanged (no-op path)."""
x, cos, sin = _make_inputs(batch=2, seq_len=16, num_heads=8, head_dim=64, cos_batch=2)
# Manually drop batch dim to create 2D cos/sin
cos_2d = cos[0]
sin_2d = sin[0]
assert cos_2d.dim() == 2
output = rope_neox.forward_native(x, cos_2d, sin_2d)
assert output.shape == x.shape
assert not torch.isnan(output).any()
assert not torch.isinf(output).any()
# ── 3D cos/sin — batch-dim stripping ──────────────────────────────
@pytest.mark.parametrize("cos_batch", [1, 2, 4])
def test_3d_cos_sin_no_error(self, rope_neox: RotaryEmbedding, cos_batch: int) -> None:
"""3D cos/sin with batch dim should not raise errors."""
x, cos, sin = _make_inputs(batch=2, seq_len=16, num_heads=8, head_dim=64, cos_batch=cos_batch)
output = rope_neox.forward_native(x, cos, sin)
assert output.shape == x.shape
@pytest.mark.parametrize("interleaved", [False, True])
def test_3d_cos_identical_to_2d(self, interleaved: bool) -> None:
"""3D cos/sin with identical batch slices == 2D cos/sin result."""
rope = RotaryEmbedding(is_neox_style=not interleaved)
B, S, H, D = 2, 16, 8, 64
x = torch.randn(B, S, H, D)
cos_2d = torch.randn(S, D // 2)
sin_2d = torch.randn(S, D // 2)
# 3D variant: expand the same 2D data across batch
cos_3d = cos_2d.unsqueeze(0).expand(B, -1, -1)
sin_3d = sin_2d.unsqueeze(0).expand(B, -1, -1)
out_2d = rope.forward_native(x, cos_2d, sin_2d)
out_3d = rope.forward_native(x, cos_3d, sin_3d)
torch.testing.assert_close(out_3d, out_2d, atol=0, rtol=0)
# ── Batch size mismatch — the regression scenario ─────────────────
@pytest.mark.parametrize(
"x_batch,cos_batch",
[
(2, 1), # cos has fewer batch elements
(1, 2), # cos has more batch elements (takes [0])
(4, 1), # large x batch, single cos
],
)
def test_batch_size_mismatch_regression(
self,
rope_neox: RotaryEmbedding,
x_batch: int,
cos_batch: int,
) -> None:
"""forward_native works when cos batch dim differs from x batch dim.
This is the exact regression scenario — before the fix, a 3D cos/sin
with a different batch size than x would cause a shape mismatch error
inside apply_rotary_emb_torch during broadcast.
"""
x, cos, sin = _make_inputs(batch=x_batch, seq_len=16, num_heads=8, head_dim=64, cos_batch=cos_batch)
output = rope_neox.forward_native(x, cos, sin)
assert output.shape == x.shape
assert output.dtype == x.dtype
# ── Batch consistency — all elements get same rotation ────────────
def test_2d_cos_broadcasts_identically_across_batch(self, rope_neox: RotaryEmbedding) -> None:
"""With 2D cos, identical x slices → identical output slices."""
B, S, H, D = 4, 16, 8, 64
x_template = torch.randn(1, S, H, D)
x = x_template.expand(B, -1, -1, -1) # all batch elements identical
cos = torch.randn(S, D // 2)
sin = torch.randn(S, D // 2)
output = rope_neox.forward_native(x, cos, sin)
# All output batch slices must be identical
for i in range(1, B):
torch.testing.assert_close(output[i], output[0], atol=0, rtol=0)
def test_3d_identical_cos_broadcasts_identically_across_batch(self, rope_neox: RotaryEmbedding) -> None:
"""With 3D cos (identical slices), identical x → identical output."""
B, S, H, D = 4, 16, 8, 64
x_template = torch.randn(1, S, H, D)
x = x_template.expand(B, -1, -1, -1)
cos = torch.randn(1, S, D // 2).expand(B, -1, -1)
sin = torch.randn(1, S, D // 2).expand(B, -1, -1)
output = rope_neox.forward_native(x, cos, sin)
for i in range(1, B):
torch.testing.assert_close(output[i], output[0], atol=0, rtol=0)
# ── Output shape / dtype invariants ───────────────────────────────
def test_output_shape_preserved(self, rope_neox: RotaryEmbedding) -> None:
"""Output shape must match input shape for all cos/sin dimensionalities."""
B, S, H, D = 2, 32, 4, 128
x = torch.randn(B, S, H, D)
# 2D cos/sin
cos_2d = torch.randn(S, D // 2)
sin_2d = torch.randn(S, D // 2)
assert rope_neox.forward_native(x, cos_2d, sin_2d).shape == (B, S, H, D)
# 3D cos/sin, matching batch
cos_3d = torch.randn(B, S, D // 2)
sin_3d = torch.randn(B, S, D // 2)
assert rope_neox.forward_native(x, cos_3d, sin_3d).shape == (B, S, H, D)
# 3D cos/sin, different batch
cos_3d_1 = torch.randn(1, S, D // 2)
sin_3d_1 = torch.randn(1, S, D // 2)
assert rope_neox.forward_native(x, cos_3d_1, sin_3d_1).shape == (B, S, H, D)
def test_output_dtype_preserved(self, rope_neox: RotaryEmbedding) -> None:
"""Output dtype must match input dtype."""
for dtype in [torch.float32, torch.float16, torch.bfloat16]:
x, cos, sin = _make_inputs(batch=2, seq_len=16, num_heads=8, head_dim=64, dtype=dtype)
output = rope_neox.forward_native(x, cos, sin)
assert output.dtype == dtype, f"dtype mismatch: {output.dtype} != {dtype}"
def test_output_no_nan_inf(
self,
rope_neox: RotaryEmbedding,
rope_gptj: RotaryEmbedding,
) -> None:
"""Output must be finite for both RoPE styles."""
for rope in (rope_neox, rope_gptj):
x, cos, sin = _make_inputs(batch=2, seq_len=32, num_heads=4, head_dim=64)
output = rope.forward_native(x, cos, sin)
assert not torch.isnan(output).any(), f"NaN in {rope}"
assert not torch.isinf(output).any(), f"Inf in {rope}"
def test_output_contiguous(self, rope_neox: RotaryEmbedding) -> None:
"""Output should be contiguous."""
x, cos, sin = _make_inputs(batch=2, seq_len=16, num_heads=8, head_dim=64)
output = rope_neox.forward_native(x, cos, sin)
assert output.is_contiguous()
# ── CFG-style doubled batch ───────────────────────────────────────
def test_cfg_style_doubled_batch(self, rope_neox: RotaryEmbedding) -> None:
"""CFG (classifier-free guidance) doubles batch — cos may have
original batch size while x has 2× batch."""
B, S, H, D = 2, 16, 8, 64
# Simulate CFG: x has 2× batch (cond + uncond concatenated)
x = torch.randn(B * 2, S, H, D)
# cos/sin only have the original batch
cos = torch.randn(B, S, D // 2)
sin = torch.randn(B, S, D // 2)
output = rope_neox.forward_native(x, cos, sin)
assert output.shape == (B * 2, S, H, D)
# ── RotaryEmbeddingWan forward_native is unchanged ────────────────
def test_wan_forward_native_unchanged(self) -> None:
"""RotaryEmbeddingWan.forward_native still uses its own implementation
(unflatten + stack + flatten) and should not crash with 3D cos/sin."""
from vllm_omni.diffusion.layers.rope import RotaryEmbeddingWan
rope = RotaryEmbeddingWan(is_neox_style=False, half_head_dim=True)
B, S, H, D = 2, 16, 8, 64
x = torch.randn(B, S, H, D)
cos = torch.randn(B, S, 1, D // 2)
sin = torch.randn(B, S, 1, D // 2)
output = rope.forward_native(x, cos, sin)
assert output.shape == x.shape
assert not torch.isnan(output).any()