[Public release 26/04] Introducing Mega MoE, FP4 Indexer and other features/fixes (#304)
* Merge with private repo * Update README * Update README * Update README * Add PyTorch requirements * Fix sync scopes for MQA logits (#256) * Update README
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@@ -11,21 +11,30 @@ def align(x: int, y: int) -> int:
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def ceil_to_ue8m0(x: torch.Tensor):
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assert x.view(-1).amax().item() > 0
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return torch.pow(2.0, torch.ceil(torch.log2(x.abs())))
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bits = x.abs().float().view(torch.int)
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exp = ((bits >> 23) & 0xFF) + (bits & 0x7FFFFF).bool().int()
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return (exp.clamp(1, 254) << 23).view(torch.float)
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def per_token_cast_to_fp8(x: torch.Tensor, use_ue8m0: bool, gran_k: int = 128) -> Tuple[torch.Tensor, torch.Tensor]:
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def pack_ue8m0_to_int(x: torch.Tensor):
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assert x.dtype == torch.float and x.size(-1) % 4 == 0
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assert (x.view(torch.int) & ((1 << 23) - 1) == 0).all()
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return (x.view(torch.int) >> 23).to(torch.uint8).view(torch.int)
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def per_token_cast_to_fp8(x: torch.Tensor, use_ue8m0: bool, gran_k: int = 128,
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use_packed_ue8m0: bool = False) -> Tuple[torch.Tensor, torch.Tensor]:
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assert x.dim() == 2
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m, n = x.shape
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padded_n = align(n, gran_k)
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x_padded = torch.empty((m, padded_n), dtype=x.dtype, device=x.device).fill_(0)
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x_padded[:, :n] = x
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x_view = x_padded.view(m, -1, gran_k)
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x_amax = x_view.abs().float().amax(dim=2).view(m, -1).clamp(1e-4)
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x_view = x_padded.view(m, padded_n // gran_k, gran_k)
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x_amax = x_view.abs().float().amax(dim=2).view(m, padded_n // gran_k).clamp(1e-4)
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sf = x_amax / 448.0
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sf = ceil_to_ue8m0(sf) if use_ue8m0 else sf
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return (x_view * (1.0 / sf.unsqueeze(2))).to(torch.float8_e4m3fn).view(m, padded_n)[:, :n].contiguous(), sf
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x_fp8 = (x_view * (1.0 / sf.unsqueeze(2))).to(torch.float8_e4m3fn).view(m, padded_n)[:, :n].contiguous()
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return x_fp8, pack_ue8m0_to_int(sf) if use_packed_ue8m0 else sf
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def per_channel_cast_to_fp8(x: torch.Tensor, use_ue8m0: bool, gran_k: int = 128) -> Tuple[torch.Tensor, torch.Tensor]:
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@@ -70,13 +79,14 @@ def _quantize_to_fp4_e2m1(x: torch.Tensor) -> torch.Tensor:
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code = idx.to(torch.uint8)
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sign = (x < 0) & (idx != 0)
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code = code | (sign.to(torch.uint8) << 3)
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return code # uint8, 0..15
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return code.view(torch.int8)
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def per_token_cast_to_fp4(x: torch.Tensor, use_ue8m0: bool, gran_k: int = 128) -> Tuple[torch.Tensor, torch.Tensor]:
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assert x.dim() == 2
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def per_token_cast_to_fp4(x: torch.Tensor, use_ue8m0: bool, gran_k: int = 128,
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use_packed_ue8m0: bool = False) -> Tuple[torch.Tensor, torch.Tensor]:
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m, n = x.shape
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assert n % 2 == 0
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assert not use_packed_ue8m0 or use_ue8m0
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padded_n = align(n, gran_k)
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x_padded = torch.zeros((m, padded_n), dtype=x.dtype, device=x.device)
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x_padded[:, :n] = x
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@@ -85,23 +95,49 @@ def per_token_cast_to_fp4(x: torch.Tensor, use_ue8m0: bool, gran_k: int = 128) -
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sf = x_amax / 6.0
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sf = ceil_to_ue8m0(sf) if use_ue8m0 else sf
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x_scaled = x_view * (1.0 / sf.unsqueeze(2))
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codes = _quantize_to_fp4_e2m1(x_scaled).view(m, padded_n) # uint8, (m, padded_n)
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codes = _quantize_to_fp4_e2m1(x_scaled).view(m, padded_n) # int8, (m, padded_n)
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codes2 = codes.view(m, padded_n // 2, 2)
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packed = (codes2[:, :, 0] & 0x0F) | ((codes2[:, :, 1] & 0x0F) << 4) # uint8
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return packed[:, :n // 2].contiguous(), sf
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packed = (codes2[:, :, 0] & 0x0F) | ((codes2[:, :, 1] & 0x0F) << 4) # int8
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return packed[:, :n // 2].contiguous(), pack_ue8m0_to_int(sf) if use_packed_ue8m0 else sf
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def transpose_packed_fp4(a: torch.Tensor) -> torch.Tensor:
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assert a.dtype == torch.uint8
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assert a.dtype == torch.int8
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assert a.dim() == 2
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m, n2 = a.shape
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n = n2 * 2
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assert (m % 2) == 0
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lo = a & 0x0F
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hi = (a >> 4) & 0x0F
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codes = torch.empty((m, n), device=a.device, dtype=torch.uint8)
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codes = torch.empty((m, n), device=a.device, dtype=torch.int8)
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codes[:, 0::2], codes[:, 1::2] = lo, hi
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codes_t = codes.transpose(0, 1).contiguous()
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codes2 = codes_t.view(n, m // 2, 2)
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out = (codes2[:, :, 0] & 0x0F) | ((codes2[:, :, 1] & 0x0F) << 4)
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return out.contiguous()
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return out.contiguous()
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def _dequantize_from_fp4_e2m1(x: torch.Tensor) -> torch.Tensor:
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fp4_values = torch.tensor([0.0, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0], device=x.device, dtype=torch.float)
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sign, value_idx = (x & 0x08) != 0, (x & 0x07).to(torch.int)
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value = fp4_values[value_idx]
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return torch.where(sign & (value_idx != 0), -value, value)
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def unpack_ue8m0_from_int(packed_sf: torch.Tensor) -> torch.Tensor:
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return (packed_sf.view(torch.uint8).to(torch.int) << 23).view(torch.float)
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def cast_back_from_fp4(packed: torch.Tensor, sf: torch.Tensor, gran_k: int = 128,
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use_packed_ue8m0: bool = False) -> torch.Tensor:
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m, n2 = packed.shape
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n = n2 * 2
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if use_packed_ue8m0:
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sf = unpack_ue8m0_from_int(sf)
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unpacked = torch.zeros((m, n), dtype=torch.int8, device=packed.device)
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unpacked[:, ::2] = packed & 0x0F
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unpacked[:, 1::2] = (packed >> 4) & 0x0F
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x_dequantized = _dequantize_from_fp4_e2m1(unpacked)
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group_idx = torch.arange(n, device=packed.device) // gran_k
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x_restored = x_dequantized * sf[:, group_idx]
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return x_restored
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