RoPE with frequencies as optional input (#1337)

* start rope with freq input

* rope with frequencies

* nits

* fix bug

* fix bug + test

* cleanup

* optional base
This commit is contained in:
Awni Hannun
2024-08-19 18:30:50 -07:00
committed by GitHub
parent 9d26441224
commit bb1b76d9dc
6 changed files with 319 additions and 69 deletions

View File

@@ -7,13 +7,18 @@ import mlx.core as mx
import mlx_tests
def rope_orig(x, dims, traditional, base, scale, offset):
def rope_orig(x, dims, traditional, base, scale, offset, freqs=None):
N = x.shape[1] + offset
dtype = x.dtype
half_D = dims // 2
positions = mx.arange(offset, N, dtype=dtype) * scale
freqs = mx.exp(-mx.arange(0.0, half_D, dtype=dtype) * (math.log(base) / half_D))
theta = mx.reshape(positions, (-1, 1)) * mx.reshape(freqs, (1, -1))
if freqs is None:
inv_freqs = mx.exp(
-mx.arange(0.0, half_D, dtype=dtype) * (math.log(base) / half_D)
)
else:
inv_freqs = 1 / freqs
theta = mx.reshape(positions, (-1, 1)) * mx.reshape(inv_freqs, (1, -1))
costheta, sintheta = mx.cos(theta), mx.sin(theta)
if traditional:
x1 = x[..., :dims:2]
@@ -138,6 +143,84 @@ class TestFast(mlx_tests.MLXTestCase):
)
self.assertLess(mx.abs(rx - rx_fast).max(), tolerances[dtype])
def test_rope_with_freqs(self):
# Check throws
T = 4
dims = 8
x = mx.random.uniform(shape=(2, T, dims))
with self.assertRaises(ValueError):
freqs = mx.random.uniform(shape=(dims - 1,))
mx.fast.rope(
x,
dims,
traditional=False,
base=None,
scale=1.0,
offset=0,
freqs=freqs,
)
with self.assertRaises(ValueError):
freqs = mx.random.uniform(shape=(1, dims))
mx.fast.rope(
x,
dims,
traditional=False,
base=None,
scale=1.0,
offset=0,
freqs=freqs,
)
freqs = mx.random.uniform(shape=(dims // 2,))
rx = rope_orig(x, dims, False, None, 1.0, 0, freqs)
rx_fast = mx.fast.rope(
x,
dims,
traditional=False,
base=None,
scale=1.0,
offset=0,
freqs=freqs,
)
self.assertLess(mx.abs(rx - rx_fast).max(), 1e-5)
# Test single vector
x = mx.random.uniform(shape=(1, 1, dims))
rx = rope_orig(x, dims, False, None, 1.0, 0, freqs)
rx_fast = mx.fast.rope(
x,
dims,
traditional=False,
base=None,
scale=1.0,
offset=0,
freqs=freqs,
)
self.assertLess(mx.abs(rx - rx_fast).max(), 1e-5)
# Test grad with freqs
f1 = lambda x, y: (rope_orig(x, dims, False, None, 1.0, 0, freqs) * y).sum()
f2 = lambda x, y: (
mx.fast.rope(
x,
dims,
traditional=False,
base=None,
scale=1.0,
offset=0,
freqs=freqs,
)
* y
).sum()
x = mx.random.uniform(shape=(2, 4, dims))
y = mx.random.uniform(shape=(2, 4, dims))
g1 = mx.grad(f1)(x, y)
g2 = mx.grad(f2)(x, y)
self.assertLess(mx.abs(g1 - g2).max(), 1e-5)
def test_rope_grad(self):
D = 32
defaults = (D, 10000.0, 1.0, 0, False)