File size: 5,519 Bytes
8daf4a7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
"""Loss curves for Qwen 1.5B / Llama 1B / Llama 3B trained on identical GRPO config.

Reads:
  --qwen-log     runs/qwen_v6/training_log.jsonl
  --llama-log    runs/llama_v3/training_log.jsonl
  --llama3b-log  runs/llama3b_v1/training_log.jsonl   (optional)

Writes:
  --output-png   eval/plots/loss_curves.png

Loss values are the GRPO surrogate loss (TRL `loss` field, written every 5 steps
by the training_log_callback). Negative values are normal — GRPO loss is the
signed advantage-weighted policy ratio; sign tells you "did the policy lean
toward higher-reward completions" but magnitude is what matters for stability.

Submission rule explicitly requires both a loss curve AND a reward curve as
committed image files. Reward curve lives in plot_combined_curves.py.
"""

from __future__ import annotations

import argparse
import json
import math
from pathlib import Path
from typing import Any

import matplotlib

matplotlib.use("Agg")
import matplotlib.pyplot as plt
import numpy as np


def _read_jsonl(path: Path) -> list[dict[str, Any]]:
    rows: list[dict[str, Any]] = []
    with path.open() as f:
        for line in f:
            line = line.strip()
            if not line:
                continue
            rows.append(json.loads(line))
    return rows


def _extract_series(rows: list[dict[str, Any]], key: str) -> tuple[np.ndarray, np.ndarray]:
    xs, ys = [], []
    for r in rows:
        v = r.get(key)
        if v is None or (isinstance(v, float) and math.isnan(v)):
            continue
        xs.append(int(r.get("step", r.get("episode", 0))))
        ys.append(float(v))
    return np.array(xs, dtype=np.float64), np.array(ys, dtype=np.float64)


def _smooth(y: np.ndarray, window: int = 3) -> np.ndarray:
    if window <= 1 or len(y) < window:
        return y.copy()
    kernel = np.ones(window, dtype=np.float64) / window
    pad = window - 1
    yp = np.concatenate([np.full(pad, y[0]), y])
    return np.convolve(yp, kernel, mode="valid")


def plot_loss(
    qwen_log: Path,
    llama_log: Path,
    output_png: Path,
    smooth_window: int = 3,
    xkcd: bool = False,
    llama3b_log: Path | None = None,
) -> None:
    qwen_rows = _read_jsonl(qwen_log)
    llama_rows = _read_jsonl(llama_log)
    llama3b_rows = _read_jsonl(llama3b_log) if llama3b_log and llama3b_log.exists() else []

    qx, qy = _extract_series(qwen_rows, "loss")
    lx, ly = _extract_series(llama_rows, "loss")
    l3x, l3y = (
        _extract_series(llama3b_rows, "loss")
        if llama3b_rows
        else (np.array([]), np.array([]))
    )

    qy_smooth = _smooth(qy, smooth_window)
    ly_smooth = _smooth(ly, smooth_window)
    l3y_smooth = _smooth(l3y, smooth_window) if len(l3y) > 0 else l3y

    output_png.parent.mkdir(parents=True, exist_ok=True)

    if xkcd:
        plt.xkcd(scale=1.0, length=100, randomness=2)
    fig, ax = plt.subplots(figsize=(11, 6), dpi=200)

    QWEN_COLOR = "#1f77b4"
    LLAMA_COLOR = "#888888"
    LLAMA3B_COLOR = "#2ca02c"

    ax.scatter(qx, qy, s=18, alpha=0.35, color=QWEN_COLOR)
    ax.plot(
        qx, qy_smooth, color=QWEN_COLOR, linewidth=2.4,
        label=f"Qwen2.5-1.5B (final loss={qy[-1]:+.4f})",
    )

    ax.scatter(lx, ly, s=18, alpha=0.35, color=LLAMA_COLOR)
    ax.plot(
        lx, ly_smooth, color=LLAMA_COLOR, linewidth=2.4,
        label=f"Llama-3.2-1B (final loss={ly[-1]:+.4f})",
    )

    if len(l3y) > 0:
        ax.scatter(l3x, l3y, s=18, alpha=0.35, color=LLAMA3B_COLOR)
        ax.plot(
            l3x, l3y_smooth, color=LLAMA3B_COLOR, linewidth=2.4,
            label=f"Llama-3.2-3B (final loss={l3y[-1]:+.4f})",
        )

    ax.axhline(0.0, color="#000000", linestyle="-", linewidth=0.8, alpha=0.5)
    ax.set_xlabel("Training step", fontsize=11)
    ax.set_ylabel("GRPO surrogate loss\n(per logging step, mean across G=4 rollouts)", fontsize=11)
    ax.set_title(
        "Viveka GRPO Training Loss — Three Architectures, Identical Config\n"
        "GRPO loss is signed; near-zero = stable, large negative = strong gradient",
        fontsize=12,
    )
    ax.grid(True, alpha=0.3, linestyle="-" if xkcd else ":")
    ax.legend(loc="upper right", frameon=True, fontsize=10)

    fig.tight_layout()
    fig.savefig(output_png, dpi=200, bbox_inches="tight")
    plt.close(fig)
    print(f"wrote {output_png}")
    print(f"  Qwen 1.5B:  n={len(qy)}  first={qy[0]:+.4f}  final={qy[-1]:+.4f}")
    print(f"  Llama 1B:   n={len(ly)}  first={ly[0]:+.4f}  final={ly[-1]:+.4f}")
    if len(l3y) > 0:
        print(f"  Llama 3B:   n={len(l3y)}  first={l3y[0]:+.4f}  final={l3y[-1]:+.4f}")


def main() -> None:
    p = argparse.ArgumentParser(description=__doc__)
    p.add_argument("--qwen-log", type=Path, default=Path("runs/qwen_v6/training_log.jsonl"))
    p.add_argument("--llama-log", type=Path, default=Path("runs/llama_v3/training_log.jsonl"))
    p.add_argument(
        "--llama3b-log", type=Path, default=Path("runs/llama3b_v1/training_log.jsonl"),
        help="Llama 3B training log (set to /dev/null to skip)",
    )
    p.add_argument("--output-png", type=Path, default=Path("eval/plots/loss_curves.png"))
    p.add_argument("--smooth-window", type=int, default=3)
    p.add_argument(
        "--xkcd", action="store_true",
        help="Render in xkcd / hand-drawn style (matches reward curve aesthetic)",
    )
    args = p.parse_args()
    plot_loss(
        args.qwen_log, args.llama_log, args.output_png,
        args.smooth_window, args.xkcd, args.llama3b_log,
    )


if __name__ == "__main__":
    main()