Merge pull request 'Implement Pearson and Spearman per-bit correleration' (#3) from dev-inter-byte-correlation into main

Reviewed-on: erickahmed/CANveyor#3

COPYRIGHT.md

@@ -0,0 +1,9 @@
+# Copyright
+
+Copyright © 2026 Erick Ahmed
+
+The source code in this repository is licensed under the **GNU Affero General Public License v3.0 or later (AGPL-3.0-or-later)**.
+
+A copy of the license is provided in the `LICENSE` file. If any discrepancy exists between this notice and the `LICENSE` file, the `LICENSE` file shall prevail.
+
+Any third-party components included in this repository at any point during developement remain the property of their respective copyright holders and are subject to their own license terms.

decoder.py

@@ -1,3 +1,7 @@
+# File: decoder.py
+# Copyright (C) 2026 Erick Ahmed
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 import argparse
 import polars as pl
 
@@ -6,11 +10,7 @@ def get_j1939_mask() -> pl.Expr:
     Returns a Polars expression representing the strict J1939 filtering rules.
     """
     id_int = pl.col("ID").str.to_integer(base=16).cast(pl.UInt32)
-    return (
-        (id_int > 0x7FF) &
-        ((id_int % 33554432 // 16777216) == 0) &
-        (pl.col("DLC") <= 8)
-    )
+    return id_int > 0x7FF
 
 def decode_j1939_metadata(lf: pl.LazyFrame) -> pl.LazyFrame:
     """
@@ -18,17 +18,18 @@ def decode_j1939_metadata(lf: pl.LazyFrame) -> pl.LazyFrame:
     """
     id_int = pl.col("ID").str.to_integer(base=16).cast(pl.UInt32)
 
-    id_shifted_8 = id_int // 256
-    id_shifted_16 = id_int // 65536
-
     priority = ((id_int // 67108864) % 8).cast(pl.UInt8)
-    pf = (id_shifted_16 % 256).cast(pl.UInt8)
-    ps = (id_shifted_8 % 256).cast(pl.UInt8)
+    pf = ((id_int // 65536) % 256).cast(pl.UInt8)
+    ps = ((id_int // 256) % 256).cast(pl.UInt8)
     sa = (id_int % 256).cast(pl.UInt8)
 
-    da = pl.when(pf < 240).then(ps).otherwise(pl.lit(255, dtype=pl.UInt8))
+    da = pl.when(pf < 240).then(ps).otherwise(pl.lit(255, dtype=pl.UInt8)).cast(pl.UInt8)
 
-    pgn = pl.when(pf < 240).then(id_shifted_8 % 65536).otherwise(id_shifted_8 % 262144).cast(pl.UInt32)
+    pgn = pl.when(pf < 240).then(
+        ((id_int // 256) & 0x3FF00)
+    ).otherwise(
+        ((id_int // 256) & 0x3FFFF)
+    ).cast(pl.UInt32)
 
     return lf.with_columns(
         pl.struct([
@@ -44,26 +45,35 @@ def decode_j1939_metadata(lf: pl.LazyFrame) -> pl.LazyFrame:
 def decode_j1939_frames(df: pl.DataFrame) -> pl.DataFrame:
     id_int = pl.col("ID").str.to_integer(base=16).cast(pl.UInt32)
 
-    is_j1939 = (id_int > 0x7FF) & ((id_int % 33554432 // 16777216) == 0) & (pl.col("DLC") <= 8)
+    is_j1939 = id_int > 0x7FF
 
-    priority = (id_int // 67108864) % 8
-    pf = (id_int // 65536) % 256
-    ps = (id_int // 256) % 256
-    sa = id_int % 256
-    da = pl.when(pf < 240).then(ps).otherwise(255)
-    pgn = pl.when(pf < 240).then((id_int // 256) % 65536).otherwise((id_int // 256) % 262144)
+    priority = ((id_int // 67108864) % 8).cast(pl.UInt8)
+    pf = ((id_int // 65536) % 256).cast(pl.UInt8)
+    ps = ((id_int // 256) % 256).cast(pl.UInt8)
+    sa = (id_int % 256).cast(pl.UInt8)
+
+    da = pl.when(pf < 240).then(ps).otherwise(pl.lit(255, dtype=pl.UInt8)).cast(pl.UInt8)
+
+    pgn = pl.when(pf < 240).then(
+        ((id_int // 256) & 0x3FF00)
+    ).otherwise(
+        ((id_int // 256) & 0x3FFFF)
+    ).cast(pl.UInt32)
 
     j1939_meta = pl.when(is_j1939).then(
         pl.struct([
-            priority.cast(pl.UInt8).alias("Priority"),
-            pf.cast(pl.UInt8).alias("PF"),
-            ps.cast(pl.UInt8).alias("PS"),
-            sa.cast(pl.UInt8).alias("SA"),
-            da.cast(pl.UInt8).alias("DA"),
-            pgn.cast(pl.UInt32).alias("PGN")
+            priority.alias("Priority"),
+            pf.alias("PF"),
+            ps.alias("PS"),
+            sa.alias("SA"),
+            da.alias("DA"),
+            pgn.alias("PGN")
         ])
     ).otherwise(None)
 
+    return df.with_columns(j1939_meta.alias("j1939_metadata"))
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="J1939 decoder")
     parser.add_argument("input_parquet", help="Path to the raw .parquet file")
@@ -72,4 +82,5 @@ if __name__ == "__main__":
 
     df = pl.scan_parquet(args.input_parquet).collect()
     decoded_df = decode_j1939_frames(df)
+
     decoded_df.write_parquet(args.output_parquet)

main.py

@@ -0,0 +1,3 @@
+# File: main.py
+# Copyright (C) 2026 Erick Ahmed
+# SPDX-License-Identifier: AGPL-3.0-or-later

parser.py

@@ -1,3 +1,7 @@
+# File: parser.py
+# Copyright (C) 2026 Erick Ahmed
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 import re
 import csv
 import polars as pl

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "CANveyor"
-version = "0.1.0"
+version = "0.0.1"
 description = "J1939 CAN bus parser that works in pair with CANdigger"
 readme = "README.md"
 requires-python = ">=3.14"

stat/correlation.py

@@ -0,0 +1,144 @@
+# File: correlation.py
+# Copyright (C) 2026 Erick Ahmed
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+import argparse
+from pathlib import Path
+
+import numpy as np
+import pandas as pd
+import plotly.graph_objects as go
+
+from utils.extractor import load_data
+
+
+def _to_int(x):
+    """Convert a hex string or integer to int, returning NaN on failure."""
+    if isinstance(x, (int, np.integer)):
+        return int(x)
+    if isinstance(x, str):
+        try:
+            return int(x, 16)
+        except ValueError:
+            return np.nan
+    return np.nan
+
+
+def calculate_correlation(df: pd.DataFrame, method: str, target_id: str | None = None) -> pd.DataFrame:
+    """Calculates inter-byte correlation grouped by identifier."""
+    byte_cols = [f"b{i}" for i in range(8)]
+    available_cols = [col for col in byte_cols if col in df.columns]
+
+    if not available_cols:
+        raise ValueError("No byte columns (b0-b7) found in the DataFrame")
+
+    df_bytes = df[["Identifier"] + available_cols].copy()
+    for col in available_cols:
+        df_bytes[col] = df_bytes[col].apply(_to_int)
+
+    if target_id:
+        group = df_bytes[df_bytes["Identifier"] == target_id]
+        if group.empty:
+            raise ValueError(f"Identifier '{target_id}' not found in data")
+        return group[available_cols].corr(method=method).fillna(0.0)
+
+    def max_abs_corr(group: pd.DataFrame) -> pd.Series:
+        corr_arr = np.abs(group.corr(method=method).to_numpy().copy())
+        np.fill_diagonal(corr_arr, 0.0)
+        return pd.Series(corr_arr.max(axis=0), index=group.columns).fillna(0.0)
+
+    return df_bytes.groupby("Identifier")[available_cols].apply(max_abs_corr)
+
+
+def plot_correlation_heatmap(corr_df: pd.DataFrame, target_id: str | None, title: str) -> go.Figure:
+    """Generates an interactive heatmap of inter-byte correlation."""
+    is_8x8 = target_id is not None
+
+    if is_8x8:
+        x = corr_df.columns.tolist()
+        y = corr_df.index.tolist()
+        z = corr_df.values
+        z_min, z_max = -1.0, 1.0
+        colorscale = [
+            [0.0, "#2c7bb6"], [0.25, "#abd9e9"], [0.5, "#ffffff"],
+            [0.75, "#fdae61"], [1.0, "#d7191c"]
+        ]
+        hover_template = "<b>%{y}</b> vs <b>%{x}</b><br>Correlation: %{z:.2f}<extra></extra>"
+    else:
+        x = corr_df.columns.tolist()
+        y = corr_df.index.tolist()
+        z = corr_df.values
+        z_min, z_max = 0.0, 1.0
+        colorscale = [
+            [0.0, "#ffffff"], [0.2, "#fff5f0"], [0.4, "#fecc5c"],
+            [0.6, "#fd8d3c"], [0.8, "#e31a1c"], [1.0, "#800026"]
+        ]
+        hover_template = "<b>%{y}</b><br>Byte %{x} max correlation: %{z:.2f}<extra></extra>"
+
+    fig = go.Figure(
+        data=go.Heatmap(
+            z=z, x=x, y=y,
+            zmin=z_min, zmax=z_max,
+            colorscale=colorscale,
+            xgap=3, ygap=3,
+            text=np.round(z, 2),
+            texttemplate="%{text}",
+            textfont={"size": 11, "color": "#2a2a2a", "family": "Segoe UI, Arial, sans-serif"},
+            hoverongaps=False,
+            hovertemplate=hover_template,
+            colorbar=dict(
+                title=dict(text="Correlation", side="top", font=dict(size=13, color="#1a1a1a")),
+                orientation="h", thickness=15, len=0.35,
+                x=1.0, xanchor="right", y=1.02, yanchor="bottom",
+                tickfont=dict(size=11, color="#2a2a2a"),
+                tickformat=".1f", outlinewidth=0.5, outlinecolor="#cccccc",
+            ),
+        )
+    )
+
+    fig.update_layout(
+        title=dict(text=title, font=dict(size=20, color="#1a1a1a"), x=0.5, xanchor="center", pad=dict(b=20)),
+        height=max(600, len(y) * 28 + 150) if not is_8x8 else 600,
+        autosize=True,
+        template="plotly_white",
+        xaxis=dict(
+            title=dict(text="Byte Position", font=dict(size=13, color="#1a1a1a")),
+            side="top" if not is_8x8 else "bottom",
+            dtick=1, showgrid=False, linecolor="#bdbdbd",
+            tickfont=dict(size=12, color="#2a2a2a"), ticks="outside", ticklen=4, tickcolor="#cccccc",
+        ),
+        yaxis=dict(
+            title=dict(text="PGN or CAN ID" if not is_8x8 else "Byte Position", font=dict(size=13, color="#1a1a1a")),
+            autorange="reversed", showgrid=False, linecolor="#bdbdbd",
+            tickfont=dict(size=12, color="#2a2a2a"), ticks="outside", ticklen=4, tickcolor="#cccccc", automargin=True,
+        ),
+        font=dict(family="Segoe UI, Arial, sans-serif", size=12, color="#2a2a2a"),
+        hoverlabel=dict(bgcolor="white", font_size=13, font_family="Segoe UI", bordercolor="#cccccc"),
+        margin=dict(l=200, r=40, t=120, b=60),
+    )
+    return fig
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Analyze CAN bus inter-byte correlation")
+    parser.add_argument("method", choices=["pearson", "spearman"], help="Correlation method to use")
+    parser.add_argument("input", type=Path, help="Path to the input CAN log file")
+    parser.add_argument("output", type=Path, nargs="?", default=Path("correlation_report.html"), help="Path to the output HTML report")
+    parser.add_argument("title", nargs="?", default="CAN Bus Inter-Byte Correlation", help="Title for the HTML report")
+    parser.add_argument("--identifier", type=str, default=None, help="Specific PGN/CAN ID to analyze (e.g., 'PGN: 65331'). If omitted, shows max correlation per byte for all IDs.")
+    args = parser.parse_args()
+
+    df = load_data(args.input)
+    corr_df = calculate_correlation(df, method=args.method, target_id=args.identifier)
+
+    display_title = f"{args.title} ({args.identifier})" if args.identifier else args.title
+    fig = plot_correlation_heatmap(corr_df, target_id=args.identifier, title=display_title)
+
+    config = {
+        "responsive": True,
+        "displaylogo": False,
+        "scrollZoom": True,
+        "modeBarButtonsToAdd": ["toggleSpikelines"],
+        "toImageButtonOptions": {"format": "png", "scale": 2},
+    }
+    fig.write_html(str(args.output), include_plotlyjs="cdn", config=config)

stat/entropy.py

@@ -0,0 +1,180 @@
+# File: entropy.py
+# Copyright (C) 2026 Erick Ahmed
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+import argparse
+from pathlib import Path
+
+import numpy as np
+import pandas as pd
+import plotly.graph_objects as go
+
+from utils.extractor import load_data
+
+
+def _to_int(x):
+    """Convert a hex string or integer to int, returning NaN on failure."""
+    if isinstance(x, (int, np.integer)):
+        return int(x)
+    if isinstance(x, str):
+        try:
+            return int(x, 16)
+        except ValueError:
+            return np.nan
+    return np.nan
+
+
+def calculate_byte_entropy(df: pd.DataFrame) -> pd.DataFrame:
+    """Calculates Shannon entropy per byte position for each identifier."""
+    byte_cols = [f"b{i}" for i in range(8)]
+    available_cols = [col for col in byte_cols if col in df.columns]
+    if not available_cols:
+        raise ValueError("No byte columns (b0-b7) found in the DataFrame")
+
+    df_bytes = df[available_cols].copy()
+    for col in available_cols:
+        df_bytes[col] = df_bytes[col].apply(_to_int)
+
+    def entropy(s: pd.Series) -> float:
+        s = s.dropna()
+        if s.empty:
+            return 0.0
+        p = s.value_counts(normalize=True)
+        return -np.sum(p * np.log2(p))
+
+    return df.groupby("Identifier")[available_cols].agg(entropy)
+
+
+def plot_entropy_heatmap(entropy_df: pd.DataFrame, title: str) -> go.Figure:
+    """Generates an interactive heatmap of byte-level Shannon entropy."""
+    x = entropy_df.columns.tolist()
+    y = entropy_df.index.tolist()
+    z = entropy_df.values
+
+    fig = go.Figure(
+        data=go.Heatmap(
+            z=z,
+            x=x,
+            y=y,
+            colorscale=[
+                [0.0, "#ffffff"],
+                [0.15, "#fff7ec"],
+                [0.35, "#fee8c8"],
+                [0.55, "#fdd49e"],
+                [0.75, "#fdbb84"],
+                [1.0, "#ef6548"],
+            ],
+            xgap=3,
+            ygap=3,
+            text=np.round(z, 2),
+            texttemplate="%{text}",
+            textfont={
+                "size": 11,
+                "color": "#2a2a2a",
+                "family": "Segoe UI, Arial, sans-serif",
+            },
+            hoverongaps=False,
+            hovertemplate=(
+                "<b>%{y}</b><br>"
+                "Byte %{x}: %{z:.2f} bits<extra></extra>"
+            ),
+            colorbar=dict(
+                title=dict(
+                    text="Entropy (bits)",
+                    side="top",
+                    font=dict(size=13, color="#1a1a1a"),
+                ),
+                orientation="h",
+                thickness=15,
+                len=0.35,
+                x=1.0,
+                xanchor="right",
+                y=1.02,
+                yanchor="bottom",
+                tickfont=dict(size=11, color="#2a2a2a"),
+                tickformat=".1f",
+                outlinewidth=0.5,
+                outlinecolor="#cccccc",
+            ),
+        )
+    )
+
+    fig.update_layout(
+        title=dict(
+            text=title,
+            font=dict(size=20, color="#1a1a1a"),
+            x=0.5,
+            xanchor="center",
+            pad=dict(b=20),
+        ),
+        height=max(600, len(y) * 28 + 150),
+        autosize=True,
+        template="plotly_white",
+        xaxis=dict(
+            title=dict(text="Byte Position", font=dict(size=13, color="#1a1a1a")),
+            side="top",
+            dtick=1,
+            showgrid=False,
+            linecolor="#bdbdbd",
+            tickfont=dict(size=12, color="#2a2a2a"),
+            ticks="outside",
+            ticklen=4,
+            tickcolor="#cccccc",
+        ),
+        yaxis=dict(
+            title=dict(text="PGN or CAN ID", font=dict(size=13, color="#1a1a1a")),
+            autorange="reversed",
+            showgrid=False,
+            linecolor="#bdbdbd",
+            tickfont=dict(size=12, color="#2a2a2a"),
+            ticks="outside",
+            ticklen=4,
+            tickcolor="#cccccc",
+            automargin=True,
+        ),
+        font=dict(family="Segoe UI, Arial, sans-serif", size=12, color="#2a2a2a"),
+        hoverlabel=dict(
+            bgcolor="white",
+            font_size=13,
+            font_family="Segoe UI",
+            bordercolor="#cccccc",
+        ),
+        margin=dict(l=200, r=40, t=120, b=60),
+    )
+    return fig
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Analyze CAN bus byte-level entropy"
+    )
+    parser.add_argument(
+        "input", type=Path, help="Path to the input CAN log file"
+    )
+    parser.add_argument(
+        "output",
+        type=Path,
+        nargs="?",
+        default=Path("entropy_report.html"),
+        help="Path to the output HTML report",
+    )
+    parser.add_argument(
+        "title",
+        nargs="?",
+        default="CAN Bus Byte-Level Entropy",
+        help="Title for the HTML report",
+    )
+    args = parser.parse_args()
+
+    df = load_data(args.input)
+    entropy_df = calculate_byte_entropy(df)
+    fig = plot_entropy_heatmap(entropy_df, title=args.title)
+
+    config = {
+        "responsive": True,
+        "displaylogo": False,
+        "scrollZoom": True,
+        "modeBarButtonsToAdd": ["toggleSpikelines"],
+        "toImageButtonOptions": {"format": "png", "scale": 2},
+    }
+    fig.write_html(str(args.output), include_plotlyjs="cdn", config=config)

stat/frequency.py

@@ -0,0 +1,116 @@
+# File: frequency.py
+# Copyright (C) 2026 Erick Ahmed
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+import argparse
+from pathlib import Path
+import pandas as pd
+import plotly.express as px
+import plotly.graph_objects as go
+from utils.extractor import load_data
+
+def calc_freq(df: pd.DataFrame) -> pd.DataFrame:
+    """Calculates frequency counts and percentages for identifiers."""
+    freq_df = df['Identifier'].value_counts().reset_index()
+    freq_df.columns = ['Identifier', 'Count']
+    total = freq_df['Count'].sum()
+    freq_df['Percentage'] = (freq_df['Count'] / total * 100).round(2)
+    return freq_df.sort_values('Count', ascending=True)
+
+def plot_freq(stats_df: pd.DataFrame, title: str) -> go.Figure:
+    """Generates interactive horizontal bar chart with log x-axis."""
+    fig = px.bar(
+        stats_df, y='Identifier', x='Count', orientation='h', title=title, log_x=True,
+        labels={'Identifier': 'PGN / CAN ID', 'Count': 'Message Count'},
+        color='Count', color_continuous_scale='Turbo',
+        range_color=(stats_df['Count'].min(), stats_df['Count'].max()),
+        hover_data={'Percentage': ':.2f', 'Count': ':,', 'Identifier': True}
+    )
+    fig.update_layout(
+        height=max(600, len(stats_df) * 18),
+        autosize=True,
+        template='plotly_white',
+        xaxis=dict(
+            title=dict(text="Message count [log scale]", font=dict(size=13, color="#1a1a1a")),
+            side="top",
+            dtick=1,
+            showgrid=False,
+            linecolor="#bdbdbd",
+            tickfont=dict(size=12, color="#2a2a2a"),
+            ticks="outside",
+            ticklen=4,
+            tickcolor="#cccccc",
+        ),
+        yaxis=dict(
+            title=dict(text="PGN or CAN ID", font=dict(size=13, color="#1a1a1a")),
+            #autorange="",
+            showgrid=False,
+            linecolor="#bdbdbd",
+            tickfont=dict(size=12, color="#2a2a2a"),
+            ticks="outside",
+            ticklen=4,
+            tickcolor="#cccccc",
+            automargin=True,
+        ),
+        font=dict(family="Segoe UI, Arial, sans-serif", size=12, color='#2a2a2a'),
+        hoverlabel=dict(bgcolor="white", font_size=13, font_family="Segoe UI",
+                        bordercolor='#cccccc'),
+        margin=dict(l=200, r=40, t=120, b=60),
+        bargap=0.35,
+        coloraxis_colorbar=dict(
+            title=dict(text='Message Count', side='top'),
+            orientation='h',
+            thickness=15,
+            len=0.35,
+            x=1.0,
+            xanchor='right',
+            y=1.02,
+            yanchor='bottom',
+            tickformat=',',
+            outlinecolor='#cccccc',
+            outlinewidth=0.5
+        ),
+        title=dict(font=dict(size=20, color='#1a1a1a'), x=0.5, xanchor='center',
+                   pad=dict(b=20))
+    )
+    fig.update_xaxes(
+        showgrid=True, gridwidth=0.5, gridcolor='#e8e8e8',
+        zeroline=False, linecolor='#bdbdbd', mirror=False,
+        tickformat=',',
+        minor=dict(showgrid=True, gridcolor='#f4f4f4', gridwidth=0.5)
+    )
+    fig.update_yaxes(
+        showgrid=False, zeroline=False, linecolor='#bdbdbd',
+        ticks='outside', ticklen=4, tickcolor='#cccccc',
+        automargin=True
+    )
+    fig.update_traces(
+        hovertemplate="<b>%{y}</b><br>Count: %{x:,}<br>Share: %{customdata[0]}%<extra></extra>",
+        marker_line_width=0,
+        texttemplate='%{x:,}',
+        textposition='outside',
+        textfont=dict(size=10, color='#666666'),
+        cliponaxis=False,
+        selected=dict(marker=dict(opacity=0.6)),
+        unselected=dict(marker=dict(opacity=0.2))
+    )
+    return fig
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Analyze CAN bus message frequency")
+    parser.add_argument("input", type=Path, help="Path to the input CAN log file")
+    parser.add_argument("output", type=Path, nargs="?", default=Path("freq_report.html"), help="Path to the output HTML report")
+    parser.add_argument("title", nargs="?", default="CAN Bus Message Frequency", help="Title for the HTML report")
+    args = parser.parse_args()
+
+    df = load_data(args.input)
+    stats = calc_freq(df)
+    fig = plot_freq(stats, title=args.title)
+    config = {
+        'responsive': True,
+        'displaylogo': False,
+        'scrollZoom': True,
+        'modeBarButtonsToAdd': ['toggleSpikelines'],
+        'toImageButtonOptions': {'format': 'png', 'scale': 2}
+    }
+    fig.write_html(str(args.output), include_plotlyjs='cdn', config=config)

stat/utils/extractor.py

@@ -0,0 +1,36 @@
+import json
+from pathlib import Path
+
+import numpy as np
+import pandas as pd
+
+def to_int(x):
+    """Convert a hex string or integer to int, returning NaN on failure."""
+    if isinstance(x, (int, np.integer)):
+        return int(x)
+    if isinstance(x, str):
+        try:
+            return int(x, 16)
+        except ValueError:
+            return np.nan
+    return np.nan
+
+def extract_id(row: pd.Series) -> str:
+    """Extracts PGN from metadata or falls back to CAN ID."""
+    meta = row.get('j1939_metadata')
+    if pd.isna(meta):
+        return f"ID: {row['ID']}"
+    if isinstance(meta, str):
+        try:
+            meta = json.loads(meta)
+        except json.JSONDecodeError:
+            return f"ID: {row['ID']}"
+    if isinstance(meta, dict) and 'PGN' in meta:
+        return f"PGN: {meta['PGN']}"
+    return f"ID: {row['ID']}"
+
+def load_data(file_path: Path) -> pd.DataFrame:
+    """Loads Parquet file and adds an Identifier column."""
+    df = pd.read_parquet(file_path)
+    df['Identifier'] = df.apply(extract_id, axis=1)
+    return df