Standalone tree split from LLMRL/projects/kda. Includes Triton dt_bias backward fix, train_k3 --preset 0.5b, SFT, Docker runtime, and tests.
116 lines
3.3 KiB
Python
116 lines
3.3 KiB
Python
# Copyright (c) 2023-2026, Songlin Yang, Yu Zhang, Zhiyuan Li
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#
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# This source code is licensed under the MIT license found in the
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# LICENSE file in the root directory of this source tree.
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# For a list of all contributors, visit:
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# https://github.com/fla-org/flash-linear-attention/graphs/contributors
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# REVISED FROM
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# https://github.com/shawntan/stickbreaking-attention/blob/main/stickbreaking_attention/sb_varlen/softplus.py
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import triton
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from triton import language as tl
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from kda._fla.utils import IS_NVIDIA
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def _generate_softplus(num_pack):
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template = """
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.reg .pred p;
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setp.gt.f32 p, ${in_reg}, 20.;
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@p mov.f32 ${out_reg}, ${in_reg};
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@!p mul.f32 ${out_reg}, ${in_reg}, 1.4426950408889634;
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@!p ex2.approx.ftz.f32 ${out_reg}, ${out_reg};
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@!p add.f32 ${out_reg}, ${out_reg}, 1.0;
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@!p lg2.approx.ftz.f32 ${out_reg}, ${out_reg};
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@!p mul.f32 ${out_reg}, ${out_reg}, 0.6931471805599453;
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"""
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out_str = ""
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for i in range(num_pack):
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inner_str = template.format(out_reg=i, in_reg=i + num_pack)
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out_str += "{" + inner_str + "}\n"
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# flatten out because torch.compile doesn't like newlines
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out_str = " ".join(out_str.split("\n"))
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return out_str
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def _generate_softplus2(num_pack):
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template = """
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.reg .pred p;
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setp.gt.f32 p, ${in_reg}, 15.;
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@p mov.f32 ${out_reg}, ${in_reg};
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@!p ex2.approx.ftz.f32 ${out_reg}, ${in_reg};
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@!p add.f32 ${out_reg}, ${out_reg}, 1.0;
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@!p lg2.approx.ftz.f32 ${out_reg}, ${out_reg};
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"""
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out_str = ""
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for i in range(num_pack):
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inner_str = template.format(out_reg=i, in_reg=i + num_pack)
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out_str += "{" + inner_str + "}\n"
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# flatten out because torch.compile doesn't like newlines
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out_str = " ".join(out_str.split("\n"))
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return out_str
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def _generate_constraints(num_pack):
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return ",".join("=r" for i in range(num_pack)) + "," + ",".join("r" for i in range(num_pack))
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_NUM_REG = 1
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s_softplus: tl.constexpr = tl.constexpr(_generate_softplus(_NUM_REG))
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s_softplus2: tl.constexpr = tl.constexpr(_generate_softplus2(_NUM_REG))
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s_constraints: tl.constexpr = tl.constexpr(_generate_constraints(_NUM_REG))
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NUM_REG: tl.constexpr = tl.constexpr(_NUM_REG)
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@triton.jit
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def softplus_nv(x):
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# equivalent to:
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# return tl.where(x < 20.0, tl.math.log(1 + tl.math.exp(x)), x)
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return tl.inline_asm_elementwise(
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asm=s_softplus,
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constraints=s_constraints,
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pack=NUM_REG,
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args=[
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x,
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],
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dtype=tl.float32,
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is_pure=True,
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)
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@triton.jit
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def softplus_triton(x):
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return tl.where(x < 20.0, tl.math.log(1 + tl.math.exp(x)), x)
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@triton.jit
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def softplus2_nv(x):
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# equivalent to:
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# return tl.where(x < 15.0, tl.math.log2(1 + tl.math.exp2(x)), x)
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return tl.inline_asm_elementwise(
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asm=s_softplus2,
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constraints=s_constraints,
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pack=NUM_REG,
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args=[
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x,
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],
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dtype=tl.float32,
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is_pure=True,
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)
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@triton.jit
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def softplus2_triton(x):
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return tl.where(x < 15.0, tl.math.log2(1 + tl.math.exp2(x)), x)
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if IS_NVIDIA:
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softplus = softplus_nv
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softplus2 = softplus2_nv
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else:
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softplus = softplus_triton
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softplus2 = softplus2_triton
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