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IQ.Pilot Release Commit @ 0798119
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207
tinygrad_repo/examples/llm.c/train_gpt2.py
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207
tinygrad_repo/examples/llm.c/train_gpt2.py
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#!/usr/bin/env python3
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import os, math, time
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import numpy as np
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from tinygrad import Tensor, nn, fetch, Device, TinyJit, GlobalCounters
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from dataclasses import dataclass
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@dataclass
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class GPTConfig:
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block_size: int = 1024
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vocab_size: int = 50257
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padded_vocab_size: int = 50304
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n_layer: int = 12
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n_head: int = 12
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n_embd: int = 768
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class CausalSelfAttention:
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def __init__(self, config:GPTConfig):
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assert config.n_embd % config.n_head == 0
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# key, query, value projections for all heads, but in a batch
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self.c_attn = nn.Linear(config.n_embd, 3 * config.n_embd)
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# output projection
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self.c_proj = nn.Linear(config.n_embd, config.n_embd)
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# regularization
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self.n_head = config.n_head
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self.n_embd = config.n_embd
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# not really a 'bias', more of a mask, but following the OpenAI/HF naming though
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self.bias = Tensor.ones(1, 1, config.block_size, config.block_size).tril()
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self.bias.is_param_(False)
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def __call__(self, x:Tensor):
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B, T, C = x.shape
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qkv = self.c_attn(x)
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q, k, v = qkv.split(self.n_embd, dim=2)
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k = k.view(B, T, self.n_head, C // self.n_head).transpose(1, 2) # (B, nh, T, hs)
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q = q.view(B, T, self.n_head, C // self.n_head).transpose(1, 2) # (B, nh, T, hs)
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v = v.view(B, T, self.n_head, C // self.n_head).transpose(1, 2) # (B, nh, T, hs)
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# manual implementation of attention
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att = (q @ k.transpose(-2, -1)) * (1.0 / math.sqrt(k.size(-1)))
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att = att.masked_fill(self.bias[:,:,:T,:T] == 0, float('-inf'))
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att = att.softmax()
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y = att @ v # (B, nh, T, T) x (B, nh, T, hs) -> (B, nh, T, hs)
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y = y.transpose(1, 2).view(B, T, C) # re-assemble all head outputs side by side
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# output projection
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y = self.c_proj(y)
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return y
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class MLP:
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def __init__(self, config:GPTConfig):
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self.c_fc = nn.Linear(config.n_embd, 4 * config.n_embd)
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self.c_proj = nn.Linear(4 * config.n_embd, config.n_embd)
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def __call__(self, x:Tensor) -> Tensor:
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return self.c_proj(self.c_fc(x).gelu())
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class Block:
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def __init__(self, config:GPTConfig):
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self.ln_1 = nn.LayerNorm(config.n_embd)
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self.attn = CausalSelfAttention(config)
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self.ln_2 = nn.LayerNorm(config.n_embd)
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self.mlp = MLP(config)
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def __call__(self, x:Tensor):
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x = x + self.attn(self.ln_1(x))
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x = x + self.mlp(self.ln_2(x))
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return x
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class GPT:
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def __init__(self, config:GPTConfig):
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self.config = config
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self.wte = nn.Embedding(config.padded_vocab_size, config.n_embd)
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self.wpe = nn.Embedding(config.block_size, config.n_embd)
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self.h = [Block(config) for _ in range(config.n_layer)]
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self.ln_f = nn.LayerNorm(config.n_embd)
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self.lm_head = nn.Linear(config.n_embd, config.padded_vocab_size, bias=False)
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self.wte.weight = self.lm_head.weight # https://paperswithcode.com/method/weight-tying
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def load_pretrained(self):
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weights = nn.state.torch_load(fetch(f'https://huggingface.co/gpt2/resolve/main/pytorch_model.bin'))
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transposed = ('attn.c_attn.weight', 'attn.c_proj.weight', 'mlp.c_fc.weight', 'mlp.c_proj.weight')
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for k in weights:
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if k == "wte.weight":
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weights[k] = weights[k].pad(((0, self.config.padded_vocab_size-self.config.vocab_size), (0,0))).to(None).contiguous()
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if k.endswith(transposed):
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weights[k] = weights[k].to(None).T.contiguous()
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# lm head and wte are tied
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weights['lm_head.weight'] = weights['wte.weight']
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nn.state.load_state_dict(self, weights)
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def generate(self, idx, max_new_tokens, temperature=1.0, top_k=None):
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for _ in range(max_new_tokens):
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idx_cond = idx if idx.shape[1] <= self.config.block_size else idx[:, -self.config.block_size:]
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logits, _ = self(idx_cond)
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logits = logits[:, -1, :] / temperature
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idx_next = logits.softmax().multinomial()
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idx = Tensor.cat(idx, idx_next, dim=1)
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return idx
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def __call__(self, idx:Tensor, targets=None):
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b, t = idx.shape
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pos = Tensor.arange(0, t, device=idx.device)
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tok_emb = self.wte(idx) # token embeddings of shape (b, t, n_embd)
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pos_emb = self.wpe(pos) # position embeddings of shape (t, n_embd)
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x = tok_emb + pos_emb
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x = self.ln_f(x.sequential(self.h))
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if targets is not None:
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logits = self.lm_head(x)[:, :, :self.config.vocab_size]
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loss = logits.sparse_categorical_crossentropy(targets)
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else:
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logits = self.lm_head(x[:, [-1], :])[:, :, :self.config.vocab_size]
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loss = None
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return logits, loss
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if __name__ == "__main__":
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import tiktoken, argparse
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parser = argparse.ArgumentParser()
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parser.add_argument("--num_iterations", type=int, default=10, help="number of iterations to run")
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parser.add_argument("--batch_size", type=int, default=4, help="batch size")
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parser.add_argument("--sequence_length", type=int, default=64, help="sequence length")
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parser.add_argument("--skip_test", action="store_true", help="skip test")
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parser.add_argument("--gpus", type=int, default=1, help="sequence length")
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args = parser.parse_args()
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B, T = args.batch_size, args.sequence_length
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assert 1 <= T <= 1024
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model = GPT(GPTConfig(n_layer=12, n_head=12, n_embd=768))
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model.load_pretrained()
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if args.gpus > 1:
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GPUS = tuple(f'{Device.DEFAULT}:{i}' for i in range(args.gpus))
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for x in nn.state.get_parameters(model): x.to_(GPUS) # we put a copy of the model on every GPU
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# init the tokenizer
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enc = tiktoken.get_encoding("gpt2")
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encode = lambda s: enc.encode(s, allowed_special={"<|endoftext|>"})
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decode = lambda l: enc.decode(l)
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# load the tokens
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# prefer to use tiny_shakespeare if it's available, otherwise use tiny_stories
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# we're using val instead of train split just because it is smaller/faster
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tokens_bin = fetch("https://huggingface.co/datasets/karpathy/llmc-starter-pack/resolve/main/tiny_shakespeare_val.bin")
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assert os.path.isfile(tokens_bin)
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print(f"loading cached tokens in {tokens_bin}")
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with open(tokens_bin, "rb") as f:
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f.seek(0x400)
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tokens = np.frombuffer(f.read(), dtype=np.uint16).astype(np.int32)
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tokens = Tensor(tokens)
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# lightweight dataloader
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def get_batch():
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assert B*T+1 <= len(tokens), "not enough tokens"
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# for 338,025 tokens. E.g. with B=8 T=1024, this will yield 41 batches before looping
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i = 0
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while True:
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x = tokens[i:i+B*T].view(B, T)
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y = tokens[i+1:i+B*T+1].view(B, T)
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yield x, y
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i += B*T
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if i + B*T + 1 >= len(tokens):
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i = 0 # in prod we'd want to randomize the start point a bit
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# forward backward for a few iterations
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data_iter = iter(get_batch())
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x, y = next(data_iter) # we'll overfit this batch below
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optimizer = nn.optim.AdamW(nn.state.get_parameters(model), lr=1e-4, weight_decay=0)
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print(f"model state: {sum(x.nbytes() for x in nn.state.get_parameters(model))/1e9:.2f} GB")
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print(f"optimizer state: {sum(x.nbytes() for x in nn.state.get_parameters(optimizer))/1e9:.2f} GB")
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# shard the data on axis 0
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if args.gpus > 1: x, y = x.shard(GPUS, axis=0), y.shard(GPUS, axis=0)
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@TinyJit
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@Tensor.train()
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def step(x:Tensor, y:Tensor) -> Tensor:
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_, loss = model(x, y)
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optimizer.zero_grad()
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loss.backward()
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return loss.realize(*optimizer.schedule_step())
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for i in range(args.num_iterations):
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GlobalCounters.reset()
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t0 = time.perf_counter()
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loss = step(x.contiguous(), y.contiguous())
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Device[Device.DEFAULT].synchronize()
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t1 = time.perf_counter()
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print(f"iteration {i}, loss: {loss.item():.6f}, time: {(t1-t0)*1000:.3f}ms, {int(B*T/(t1-t0))} tok/s, {GlobalCounters.global_mem/1e9:.2f} GB")
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if not args.skip_test:
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# copy back to single gpu for test
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if args.gpus > 1:
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for x in nn.state.get_parameters(model): x.to_(Device.DEFAULT)
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start = "<|endoftext|>"
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start_ids = encode(start)
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x = (Tensor(start_ids)[None, ...])
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max_new_tokens = 16
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temperature = 1.0
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top_k = 40
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y = model.generate(x, max_new_tokens, temperature=temperature, top_k=top_k)
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print(decode(y[0].tolist()))
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