"""本课独立实验；在仓库根目录执行 .venv/bin/python lessons/06/experiment.py。"""
import sys, json, math
from pathlib import Path
sys.path.insert(0, str(Path(__file__).resolve().parents[2]))
import torch
from torch import nn
from torch.nn import functional as F
from poetry_gpt.common import ROOT, DEFAULT_DATA, read_json, read_jsonl
from poetry_gpt.model import ModelConfig, PoetryGPT, CausalAttention, Block
from poetry_gpt.data import Tokenizer, SPECIAL, clean_record, keywords_for
from poetry_gpt.labs import show
torch.set_num_threads(2)
torch.manual_seed(26)

logits = torch.tensor([[2.0, 1.0, 0.0]])
p = logits.softmax(-1)
show('候选 月 山 水', p.tolist())
show('正确字为 月 的误差', F.cross_entropy(logits, torch.tensor([0])).item())
show('手算 -ln(正确字概率)', -math.log(p[0, 0].item()))