Inference.py

import json  
import numpy as np  
import pandas as pd
import tensorflow as tf  
from tensorflow.keras import layers 
import sentencepiece as spm  
import requests

# ⬇️ 토크나이저 불러오기
sp = spm.SentencePieceProcessor()
sp.load("ko_unigram.model")

# ⬇️ 특수 토큰 ID 추출
pad_id = sp.piece_to_id("<pad>") if sp.piece_to_id("<pad>") != -1 else 0  
start_id = sp.piece_to_id("<start>")  
sep_id = sp.piece_to_id("<sep>")  
end_id = sp.piece_to_id("<end>")  
unk_id = sp.piece_to_id("<unk>")  

vocab_size = sp.get_piece_size()
print(f"✅ Vocabulary size: {vocab_size}")

# ⬇️ 텍스트 <-> ID 변환 함수
def text_to_ids(text):
    return sp.encode(text, out_type=int)

def ids_to_text(ids):
    return sp.decode(ids)

max_len = 100
batch_size = 128

class Lo(layers.Layer):
    def __init__(self, d_model):
        super().__init__()
        # 내부 계산은 float32로 유지
        self.proj = layers.Dense(d_model, use_bias=True, dtype='float32')
        self.p = layers.Dense(96, use_bias=True, dtype='float32')
        self._out_dtype = 'float32'

    def call(self, x):
        # x may be bfloat16; cast to float32 for stable intermediate computation
        x_f32 = tf.cast(x, tf.float32)
        x = self.proj(x_f32)
        x = tf.nn.gelu(x)
        x = self.p(x)
        # cast back to model dtype for consistency
        return tf.cast(x, self._out_dtype)

class LoSoU(layers.Layer):
    """
    안정화된 LoSoU 레이어 (동적 alpha 사용)
    - alpha 값을 입력에 따라 동적으로 계산: alpha = sigmoid(Linear(x))
    - 누적합 대신 지수이동평균(EMA) 사용 (alpha: smoothing factor)
    - 내부 계산은 float32로 수행 (TPU bfloat16 안정성 향상)
    - EMA 결과 클리핑 및 작은 epsilon 적용
    - 안전한 split 처리 (짝수 차원 가정; 아니라면 마지막 차원 pad 필요)
    """
    def __init__(self, d_model, clip_value=5.0, eps=1e-6):
        super().__init__()
        # 대부분 연산을 float32로 수행
        self.d_model = d_model
        self.clip_value = float(clip_value)
        self.eps = float(eps)

        # projection / gating layers in float32
        self.Q = layers.Dense(96, dtype='float32')
        self.K = layers.Dense(96, dtype='float32')
        self.V = Lo(d_model)  # Lo already handles casting to model dtype; we'll cast back to float32
        self.proj = layers.Dense(d_model, use_bias=True, dtype='float32')
        self.O = layers.Dense(d_model, dtype='float32')
        self.norm = layers.LayerNormalization(epsilon=1e-5, dtype='float32')

        # 동적 alpha 계산을 위한 레이어
        # alpha는 [0, 1] 범위여야 하므로 sigmoid 사용
        # 입력 x의 d_model 차원을 사용하여 각 샘플에 대해 alpha 계산
        # 예: (B, L, d_model) -> (B, L, 1) -> (B, L, 1) with sigmoid
        # 또는 (B, L, d_model) -> (B, L, d_model) -> global reduce -> (B, L, 1)
        # 간단히 각 위치에 대해 동일한 alpha 사용 (입력의 평균 기반)
        # 또는 위치별로 다르게 사용 (각 위치에 대해 계산)
        # 여기서는 위치별로 다르게 계산 (B, L, 1)
        self.alpha_linear = layers.Dense(1, activation='sigmoid', dtype='float32')

    def _ema_over_time(self, score, alpha_dynamic):
        # score: (B, L, D) float32 in [0,1] roughly
        # alpha_dynamic: (B, L, 1) float32 in [0,1]

        # transpose to (L, B, D) to scan over time steps
        seq = tf.transpose(score, perm=[1, 0, 2])  # (L, B, D)
        alpha_seq = tf.transpose(alpha_dynamic, perm=[1, 0, 2])  # (L, B, 1)

        def step(prev_ema, inputs):
            x_t, alpha_t = inputs
            # prev_ema: (B, D), x_t: (B, D), alpha_t: (B, 1)
            new = alpha_t * x_t + (1.0 - alpha_t) * prev_ema
            return new

        # 초기값을 첫 step 값으로 설정
        init = seq[0]  # (B, D)
        first_alpha = alpha_seq[0]  # (B, 1)

        # scan의 elems는 (L-1, B, D) 및 (L-1, B, 1) 이어야 함
        remaining_seq = seq[1:]  # (L-1, B, D)
        remaining_alpha = alpha_seq[1:]  # (L-1, B, 1)

        # elems는 두 텐서의 튜플로 구성: (x_t, alpha_t)
        elems = (remaining_seq, remaining_alpha)

        ema_seq = tf.scan(fn=step, elems=elems, initializer=init)
        # 초기값 포함
        ema_seq = tf.concat([tf.expand_dims(init, 0), ema_seq], axis=0)  # (L, B, D)

        # transpose back to (B, L, D)
        ema = tf.transpose(ema_seq, perm=[1, 0, 2])
        return ema

    def call(self, x):
        # x: (B, L, d_model) maybe bfloat16 or float32
        # cast to float32 for all internal computations
        x_f32 = tf.cast(x, tf.float32)
        residual = x_f32

        # Q, K, V
        q = self.Q(x_f32)   # (B, L, 96)
        k = self.K(x_f32)   # (B, L, 96)
        V = tf.cast(self.V(x), tf.float32)  # ensure V's output is float32

        # gating signals in (0,1)
        g_q = tf.nn.sigmoid(q)
        g_k = tf.nn.sigmoid(k)

        # elementwise product -> bounded roughly [0,1]
        score = g_q * g_k

        # 동적 alpha 계산: (B, L, d_model) -> (B, L, 1)
        alpha_dynamic = self.alpha_linear(x_f32) # (B, L, 1)
        # 필요시 alpha_dynamic에 대한 후처리 (예: min/max 등) 가능
        # ex: alpha_dynamic = tf.clip_by_value(alpha_dynamic, 0.01, 0.99)

        # EMA across time (stable alternative to cumsum)
        score_ema = self._ema_over_time(score, alpha_dynamic)

        # optionally normalize by (mean + eps) across last dim to reduce scale variations
        mean_last = tf.reduce_mean(score_ema, axis=-1, keepdims=True)  # (B, L, 1)
        denom = tf.maximum(mean_last, self.eps)
        score_norm = score_ema / denom

        # clip to avoid extremes
        score_clipped = tf.clip_by_value(score_norm, -self.clip_value, self.clip_value)

        # combine with V
        x_comb = score_clipped * V  # (B, L, d_model)

        out = self.proj(x_comb)  # (B, L, d_model)

        # ensure out dim even for split
        d = out.shape[-1]  # this is an int (static shape)
        if d is not None and d % 2 == 1:
            out = tf.pad(out, [[0,0],[0,0],[0,1]])

        a, b = tf.split(out, 2, axis=-1)
        gated = tf.nn.silu(a) * b
        out = self.O(gated)

        out = self.norm(out + residual)

        # cast back to original dtype for downstream layers
        return tf.cast(out, x.dtype)


class Block(layers.Layer):
    def __init__(self, d_model, hyper_n):
        super().__init__()
        self.losou = [LoSoU(d_model) for _ in range(hyper_n)]

    def call(self, x):
        for losou in self.losou:
            x = losou(x)
        return x

class ReLaM(tf.keras.Model):
    def __init__(self, vocab_size, max_seq_len, d_model, n_layers, dropout_rate=0.1):
        super().__init__()
        self.token_embedding = layers.Embedding(vocab_size, d_model)
        self.pos_embedding = layers.Embedding(max_seq_len, d_model)
        self.blocks = [Block(d_model, hyper_n=3) for _ in range(n_layers)]

        # LayerNormalization은 float32로 해서 정밀도 문제 방지
        self.ln_f = layers.LayerNormalization(epsilon=1e-5, dtype="float32")

    def call(self, x, training=False):
        batch_size, seq_len = tf.shape(x)[0], tf.shape(x)[1]
        positions = tf.range(seq_len)[tf.newaxis, :]

        x = self.token_embedding(x) + self.pos_embedding(positions)
        for block in self.blocks:
            x = block(x)

        x = self.ln_f(x)

        embedding_matrix = tf.cast(self.token_embedding.embeddings, x.dtype)
        logits = tf.matmul(x, embedding_matrix, transpose_b=True)
        return tf.cast(logits, tf.float32)

# 모델 생성
model = ReLaM(
    vocab_size=vocab_size,
    max_seq_len=max_len,
    d_model=256,
    n_layers=1
)

dummy_input = tf.zeros((1, max_len), dtype=tf.int32)
_ = model(dummy_input)
model.load_weights('/content/Cobra.weights.h5')
print("모델 가중치 로드 완료!")

def generate_text_topp(model, prompt, max_len=100, max_gen=98, p=0.9, temperature=0.8, min_len=30):
    model_input = text_to_ids(f"<start> {prompt} <sep>")
    model_input = model_input[:max_len]
    generated = list(model_input)
    for step in range(max_gen):
        if len(generated) > max_len:
            input_seq = generated[-max_len:]
        else:
            input_seq = generated
        input_padded = np.pad(input_seq, (0, max_len - len(input_seq)), constant_values=pad_id)
        input_tensor = tf.convert_to_tensor([input_padded])
        logits = model(input_tensor, training=False)
        next_token_logits = logits[0, len(input_seq) - 1].numpy()
        next_token_logits[end_id] -= 5.0
        next_token_logits[pad_id] -= 10.0
        probs = tf.nn.softmax(next_token_logits / temperature).numpy()
        sorted_indices = np.argsort(probs)[::-1]
        sorted_probs = probs[sorted_indices]
        cumulative_probs = np.cumsum(sorted_probs)
        cutoff = np.searchsorted(cumulative_probs, p)
        top_indices = sorted_indices[:cutoff + 1]
        top_probs = sorted_probs[:cutoff + 1]
        top_probs /= np.sum(top_probs)
        next_token_id = np.random.choice(top_indices, p=top_probs)
        if next_token_id == end_id and len(generated) >= min_len:
            break
        generated.append(int(next_token_id))
    return ids_to_text(generated)

print("\n\n===== 생성 결과 =====")  
print(generate_text_topp(model, "제가 이따가 버스를 타야 해서 준비 좀 해야겠어요. 재미있는 대화였습니다!", p=0.8))