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feat: allow relative position (#156)
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import re
from flax.core.frozen_dict import freeze
from flax.traverse_util import flatten_dict, unflatten_dict
from jax.experimental import PartitionSpec as P
# utils adapted from https://github.com/google-research/google-research/blob/master/flax_models/t5x/partitions.py
# Sentinels
_unmatched = object()
# For specifying empty leaf dict `{}`
empty_dict = object()
def _match(qs, ks):
"""Return True if regexes in qs match any window of strings in tuple ks."""
# compile regexes and force complete match
qts = tuple(map(lambda x: re.compile(x + "$"), qs))
for i in range(len(ks) - len(qs) + 1):
matches = [x.match(y) for x, y in zip(qts, ks[i:])]
if matches and all(matches):
return True
return False
def _replacement_rules(rules):
def replace(key, val):
for rule, replacement in rules:
if _match(rule, key):
return replacement
return val
return replace
def _get_partition_rules():
return [
# embeddings
(("embed_positions", "embedding"), P("mp", None)),
(("embed_tokens", "embedding"), P("mp", None)),
(("rel_bias", "embedding"), P(None, "mp")),
# attention
(("(q_proj|k_proj|v_proj)", "kernel"), P(None, "mp")),
(("out_proj", "kernel"), P("mp", None)),
# FFN
(("Dense_0", "kernel"), P(None, "mp")),
(("GLU.*", "Dense_1", "kernel"), P(None, "mp")),
(("GLU.*", "Dense_2", "kernel"), P("mp", None)),
(("FFN.*", "Dense_1", "kernel"), P("mp", None)),
# layer norms
(("(bias|scale)",), None),
(("lm_head", "kernel"), P(None, "mp")),
# head scale and tau
(("(head_scale|tau)",), None),
]
def set_partitions(in_dict):
rules = _get_partition_rules()
replace = _replacement_rules(rules)
initd = {k: _unmatched for k in flatten_dict(in_dict)}
result = {k: replace(k, v) for k, v in initd.items()}
for k, v in result.items():
if v == _unmatched:
print(f"Unmatched -> {k}")
assert _unmatched not in result.values(), "Incomplete partition spec."
return freeze(unflatten_dict(result))