flash-attention/tests/losses/test_cross_entropy_apex.py
2022-11-12 21:58:41 -08:00

40 lines
1.4 KiB
Python

import math
import torch
import torch.nn.functional as F
import pytest
from einops import rearrange
from src.losses.cross_entropy_apex import CrossEntropyLossApex
is_sm8x = torch.cuda.get_device_capability('cuda')[0] >= 8
@pytest.mark.parametrize('dtype', [torch.float16, torch.float32] + ([torch.bfloat16] if is_sm8x else []))
# @pytest.mark.parametrize('dtype', [torch.float16])
@pytest.mark.parametrize('inplace_backward', [False, True])
# @pytest.mark.parametrize('inplace_backward', [False])
@pytest.mark.parametrize('vocab_size', [50257])
def test_cross_entropy_loss_apex(vocab_size, inplace_backward, dtype):
device = 'cuda'
rtol, atol = (1e-5, 1e-6) if dtype == torch.float32 else (1e-3, 1e-4)
# set seed
torch.random.manual_seed(0)
batch_size = 8
seqlen = 128
x_pt = torch.randn(batch_size * seqlen, vocab_size, device=device, dtype=dtype, requires_grad=True)
x = x_pt.detach().clone().requires_grad_()
y = torch.randint(0, vocab_size, (batch_size * seqlen,), dtype=torch.long, device=device)
y[torch.randperm(batch_size * seqlen)[:10]] = -100
model_pt = torch.nn.CrossEntropyLoss()
model = CrossEntropyLossApex(inplace_backward=inplace_backward)
out = model(x, y)
out_pt = model_pt(x_pt.float(), y)
assert torch.allclose(out, out_pt, rtol=rtol, atol=atol)
g = torch.randn_like(out)
out_pt.backward(g)
out.backward(g)
assert torch.allclose(x.grad, x_pt.grad, rtol=rtol, atol=atol)