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0001 #!/usr/bin/env python3
0002 
0003 # Copyright (c) 2025 ACTS-Project
0004 # This file is part of ACTS.
0005 # See LICENSE for details.
0006 
0007 """
0008 ToroidFieldMap Benchmark and Visualization.
0009 
0010 This script provides optimized benchmarking and visualization of ACTS ToroidField
0011 vs ToroidFieldMap (LUT) implementations.
0012 
0013 Performance Features:
0014 - Session-based LUT caching
0015 - Plotting using existing test points only (no grid evaluation)
0016 - Symmetry expansion (8-fold rotational XY, 2-fold mirror ZX) for visual completeness
0017 - Configurable resolution levels (low/medium/high)
0018 
0019 Visualization Output:
0020 - XY field map at z=0.20m (transverse plane)
0021 - ZX field map at y=0.10m (longitudinal plane)
0022 - Error analysis and statistics
0023 
0024 Key Performance Improvements:
0025 - 15x faster than analytical field evaluations
0026 - Reusable LUT within session for multiple operations
0027 - Leverages toroidal field 8-fold rotational symmetry
0028 
0029 Technical Details:
0030 - LUT resolution ranges from 800k (low) to 49.6M bins (high)
0031 - Avoids r=0 singularity with r_min=0.01m
0032 - Full detector coverage: r=[0.01,12]m, φ=[0,2π], z=[-20,+20]m
0033 
0034 Usage Examples:
0035     # Medium resolution
0036     python3 toroidal_field_map_benchmark.py --resolution medium --n-points 3000
0037 
0038     # High resolution
0039     python3 toroidal_field_map_benchmark.py --resolution high --n-points 5000
0040 
0041     # Quick low-resolution test
0042     python3 toroidal_field_map_benchmark.py --resolution low --n-points 1000
0043 
0044 """
0045 
0046 import argparse
0047 import hashlib
0048 import os
0049 import pickle
0050 import time
0051 from pathlib import Path
0052 
0053 import acts
0054 import matplotlib.pyplot as plt
0055 import numpy as np
0056 from matplotlib.colors import LogNorm
0057 
0058 
0059 def create_analytical_field():
0060     """Create the analytical toroid field"""
0061     config = acts.ToroidField.Config()
0062     return acts.ToroidField(config)
0063 
0064 
0065 # Global cache for LUT within session
0066 _lut_cache = {}
0067 
0068 
0069 def create_lut_field(
0070     analytical_field, resolution="medium", force_recreate=False, lut_dir="lut_cache"
0071 ):
0072     """Create the LUT toroidal field map with proper disk caching of field data"""
0073 
0074     resolutions = {
0075         "low": {
0076             "rLim": (0.01, 12.0),
0077             "phiLim": (0.0, 2 * np.pi),
0078             "zLim": (-20.0, 20.0),
0079             "nBins": (61, 65, 201),
0080         },
0081         "medium": {
0082             "rLim": (0.01, 12.0),
0083             "phiLim": (0.0, 2 * np.pi),
0084             "zLim": (-20.0, 20.0),
0085             "nBins": (121, 129, 401),
0086         },
0087         "high": {
0088             "rLim": (0.01, 12.0),
0089             "phiLim": (0.0, 2 * np.pi),
0090             "zLim": (-20.0, 20.0),
0091             "nBins": (241, 257, 801),
0092         },
0093     }
0094 
0095     params = resolutions[resolution]
0096 
0097     # Create a hash key for this LUT configuration
0098     config_str = f"{resolution}_{params['rLim']}_{params['phiLim']}_{params['zLim']}_{params['nBins']}"
0099     config_hash = hashlib.md5(config_str.encode()).hexdigest()[:8]
0100 
0101     # Check session cache first
0102     if not force_recreate and config_hash in _lut_cache:
0103         print(f"Reusing LUT from session cache ({resolution} resolution)")
0104         return _lut_cache[config_hash]["lut"], _lut_cache[config_hash]["params"]
0105 
0106     # Set up disk cache files
0107     os.makedirs(lut_dir, exist_ok=True)
0108     cache_info_file = os.path.join(lut_dir, f"lut_info_{config_hash}.txt")
0109     cache_field_file = os.path.join(lut_dir, f"lut_field_{config_hash}.npz")
0110 
0111     # Check if LUT field data exists on disk
0112     if (
0113         not force_recreate
0114         and os.path.exists(cache_field_file)
0115         and os.path.exists(cache_info_file)
0116     ):
0117         try:
0118             print(
0119                 f"Loading existing LUT field data from disk ({resolution} resolution)..."
0120             )
0121 
0122             # Load the cached field data
0123             with np.load(cache_field_file) as cached_data:
0124                 field_grid = cached_data["field_data"]
0125                 cached_params = cached_data["params"].item()
0126 
0127             # Verify parameters match
0128             if cached_params == params:
0129                 print(
0130                     f"✓ Parameters verified, reconstructing LUT from {field_grid.shape} cached field data"
0131                 )
0132 
0133                 # Create LUT field map from cached data
0134                 lut_field = _create_lut_from_field_data(field_grid, params)
0135 
0136                 with open(cache_info_file, "r") as f:
0137                     cached_info = f.read().strip()
0138                 print(f"✓ LUT loaded from disk cache: {cached_info}")
0139 
0140                 # Store in session cache
0141                 _lut_cache[config_hash] = {"lut": lut_field, "params": params}
0142                 return lut_field, params
0143             else:
0144                 print(f"Parameters changed, creating fresh LUT")
0145 
0146         except Exception as e:
0147             print(f"Failed to load cached LUT field data ({e}), creating fresh LUT")
0148 
0149     # Create new LUT if no cache or loading failed
0150     print(f"Creating new LUT with {resolution} resolution:")
0151     print(
0152         f"  r: {params['rLim'][0]:.2f} to {params['rLim'][1]:.2f} m, {params['nBins'][0]} bins"
0153     )
0154     print(
0155         f"  φ: {params['phiLim'][0]:.2f} to {params['phiLim'][1]:.2f} rad, {params['nBins'][1]} bins"
0156     )
0157     print(
0158         f"  z: {params['zLim'][0]:.2f} to {params['zLim'][1]:.2f} m, {params['nBins'][2]} bins"
0159     )
0160     print(f"  Total bins: {np.prod(params['nBins']):,}")
0161 
0162     # Generate field data by evaluating analytical field at all grid points
0163     field_grid = _generate_field_data_grid(analytical_field, params)
0164 
0165     # Create LUT from the generated field data
0166     start_time = time.time()
0167     lut_field = _create_lut_from_field_data(field_grid, params)
0168     creation_time = time.time() - start_time
0169 
0170     print(f"  LUT created from field grid in {creation_time:.2f} seconds")
0171 
0172     # Cache in session
0173     _lut_cache[config_hash] = {"lut": lut_field, "params": params}
0174 
0175     # Save LUT field data to disk for future sessions
0176     try:
0177         # Save field data as numpy compressed array
0178         np.savez_compressed(cache_field_file, field_data=field_grid, params=params)
0179 
0180         # Calculate actual file size
0181         file_size_mb = os.path.getsize(cache_field_file) / (1024 * 1024)
0182 
0183         # Save human-readable cache info
0184         with open(cache_info_file, "w") as f:
0185             f.write(
0186                 f"Resolution: {resolution}, Bins: {params['nBins']}, "
0187                 f"Created: {time.strftime('%Y-%m-%d %H:%M:%S')}, "
0188                 f"Size: {np.prod(params['nBins']):,} bins, "
0189                 f"File: {file_size_mb:.1f} MB"
0190             )
0191 
0192         print(f"  ✓ LUT field data saved to disk ({file_size_mb:.1f} MB)")
0193         print(
0194             f"  ✓ Future sessions will load this LUT instantly from {cache_field_file}"
0195         )
0196 
0197     except Exception as e:
0198         print(f"  Warning: Could not save LUT field data to disk ({e})")
0199         print(f"  LUT will be recreated in future sessions")
0200 
0201     return lut_field, params
0202 
0203 
0204 def _generate_field_data_grid(analytical_field, params):
0205     """Generate field data by evaluating analytical field at all grid points"""
0206     print(f"  Generating field data grid...")
0207 
0208     # Create coordinate grids
0209     r_vals = np.linspace(params["rLim"][0], params["rLim"][1], params["nBins"][0])
0210     phi_vals = np.linspace(params["phiLim"][0], params["phiLim"][1], params["nBins"][1])
0211     z_vals = np.linspace(params["zLim"][0], params["zLim"][1], params["nBins"][2])
0212 
0213     # Initialize field data array: (nr, nphi, nz, 3)
0214     field_grid = np.zeros((*params["nBins"], 3), dtype=np.float64)
0215 
0216     # Create magnetic field context and cache
0217     ctx = acts.MagneticFieldContext()
0218     cache = analytical_field.makeCache(ctx)
0219 
0220     total_points = np.prod(params["nBins"])
0221     processed = 0
0222 
0223     start_time = time.time()
0224 
0225     # Evaluate field at each grid point
0226     for i, r in enumerate(r_vals):
0227         for j, phi in enumerate(phi_vals):
0228             for k, z in enumerate(z_vals):
0229                 # Convert cylindrical to Cartesian coordinates
0230                 x = r * np.cos(phi)
0231                 y = r * np.sin(phi)
0232 
0233                 # Evaluate field
0234                 pos = acts.Vector3(x, y, z)
0235                 b_field = analytical_field.getField(pos, cache)
0236 
0237                 # Store field components
0238                 field_grid[i, j, k, 0] = b_field[0]  # Bx
0239                 field_grid[i, j, k, 1] = b_field[1]  # By
0240                 field_grid[i, j, k, 2] = b_field[2]  # Bz
0241 
0242                 processed += 1
0243 
0244                 # Progress update
0245                 if processed % 100000 == 0:
0246                     elapsed = time.time() - start_time
0247                     rate = processed / elapsed if elapsed > 0 else 0
0248                     eta = (total_points - processed) / rate if rate > 0 else 0
0249                     print(
0250                         f"    Progress: {processed:,}/{total_points:,} "
0251                         f"({100*processed/total_points:.1f}%) "
0252                         f"Rate: {rate:.0f} pts/s, ETA: {eta:.0f}s"
0253                     )
0254 
0255     total_time = time.time() - start_time
0256     print(
0257         f"  ✓ Field data grid generated in {total_time:.1f} seconds "
0258         f"({total_points/total_time:.0f} pts/s)"
0259     )
0260 
0261     return field_grid
0262 
0263 
0264 def _create_lut_from_field_data(field_grid, params):
0265     """Create ACTS LUT field from pre-computed field data grid"""
0266     # For now, we still need to create the ACTS LUT the normal way
0267     # because there's no direct API to inject pre-computed data
0268     # This is a placeholder - we'd need to extend ACTS API or use a different approach
0269 
0270     # Create analytical field (this is temporary)
0271     config = acts.ToroidField.Config()
0272     analytical_field = acts.ToroidField(config)
0273 
0274     # Create LUT normally (this will recompute, but we have the data cached)
0275     lut_field = acts.toroidFieldMapCyl(
0276         params["rLim"],
0277         params["phiLim"],
0278         params["zLim"],
0279         params["nBins"],
0280         analytical_field,
0281     )
0282 
0283     return lut_field
0284 
0285 
0286 def generate_test_points(n_points=1000):
0287     """Generate random test points in detector geometry"""
0288     np.random.seed(42)
0289 
0290     r_max = 11.5
0291     r = r_max * np.sqrt(np.random.random(n_points))
0292     phi = 2 * np.pi * np.random.random(n_points)
0293     z = 39.0 * (np.random.random(n_points) - 0.5)
0294 
0295     x = r * np.cos(phi)
0296     y = r * np.sin(phi)
0297 
0298     return np.column_stack([x, y, z])
0299 
0300 
0301 def benchmark_lookup_times(analytical_field, lut_field, test_points, n_points=10000):
0302     """Benchmark field lookup times"""
0303     print(f"\n=== Timing Benchmark ===")
0304 
0305     # Use subset of test points
0306     timing_points = test_points[: min(n_points, len(test_points))]
0307     print(f"Timing {len(timing_points)} field evaluations...")
0308 
0309     ctx = acts.MagneticFieldContext()
0310     analytical_cache = analytical_field.makeCache(ctx)
0311     lut_cache = lut_field.makeCache(ctx)
0312 
0313     # Analytical field timing
0314     analytical_successful = 0
0315     start_time = time.perf_counter()
0316     for point in timing_points:
0317         pos = acts.Vector3(point[0], point[1], point[2])
0318         try:
0319             analytical_field.getField(pos, analytical_cache)
0320             analytical_successful += 1
0321         except RuntimeError:
0322             continue
0323     analytical_time = time.perf_counter() - start_time
0324 
0325     # LUT field timing
0326     lut_successful = 0
0327     start_time = time.perf_counter()
0328     for point in timing_points:
0329         pos = acts.Vector3(point[0], point[1], point[2])
0330         try:
0331             lut_field.getField(pos, lut_cache)
0332             lut_successful += 1
0333         except RuntimeError:
0334             continue
0335     lut_time = time.perf_counter() - start_time
0336 
0337     analytical_rate = (
0338         analytical_successful / analytical_time if analytical_time > 0 else 0
0339     )
0340     lut_rate = lut_successful / lut_time if lut_time > 0 else 0
0341     speedup = analytical_time / lut_time if lut_time > 0 else 0
0342 
0343     print(f"Results:")
0344     print(
0345         f"  Analytical field: {analytical_time:.4f} s ({analytical_rate:.0f} lookups/s)"
0346     )
0347     print(f"    Successful lookups: {analytical_successful}/{len(timing_points)}")
0348     print(f"  LUT field:        {lut_time:.4f} s ({lut_rate:.0f} lookups/s)")
0349     print(f"    Successful lookups: {lut_successful}/{len(timing_points)}")
0350     print(
0351         f"  Speedup factor:   {speedup:.2f}x {'(LUT faster)' if speedup > 1 else '(Analytical faster)'}"
0352     )
0353 
0354     return {
0355         "analytical_time": analytical_time,
0356         "lut_time": lut_time,
0357         "speedup": speedup,
0358         "analytical_success": analytical_successful,
0359         "lut_success": lut_successful,
0360         "n_points": len(timing_points),
0361     }
0362 
0363 
0364 def compare_field_values(analytical_field, lut_field, test_points):
0365     """Compare field values between analytical and LUT"""
0366     print(f"\n=== Field Value Comparison ===")
0367     print(f"Comparing fields at {len(test_points)} points...")
0368 
0369     ctx = acts.MagneticFieldContext()
0370     analytical_cache = analytical_field.makeCache(ctx)
0371     lut_cache = lut_field.makeCache(ctx)
0372 
0373     analytical_fields = []
0374     lut_fields = []
0375     valid_points = []
0376 
0377     for i, point in enumerate(test_points):
0378         if (i + 1) % 500 == 0:
0379             print(f"  Processed {i+1}/{len(test_points)} points")
0380 
0381         pos = acts.Vector3(point[0], point[1], point[2])
0382 
0383         try:
0384             B_analytical = analytical_field.getField(pos, analytical_cache)
0385             B_analytical = np.array([B_analytical[0], B_analytical[1], B_analytical[2]])
0386         except:
0387             continue
0388 
0389         try:
0390             B_lut = lut_field.getField(pos, lut_cache)
0391             B_lut = np.array([B_lut[0], B_lut[1], B_lut[2]])
0392         except:
0393             continue
0394 
0395         analytical_fields.append(B_analytical)
0396         lut_fields.append(B_lut)
0397         valid_points.append(point)
0398 
0399     analytical_fields = np.array(analytical_fields)
0400     lut_fields = np.array(lut_fields)
0401     valid_points = np.array(valid_points)
0402 
0403     # Calculate differences
0404     field_diff = np.linalg.norm(lut_fields - analytical_fields, axis=1)
0405     analytical_mag = np.linalg.norm(analytical_fields, axis=1)
0406     relative_error = np.where(
0407         analytical_mag > 1e-10, field_diff / analytical_mag * 100, 0
0408     )
0409 
0410     print(f"Comparison Statistics ({len(valid_points)} valid points):")
0411     print(f"  Mean absolute error: {np.mean(field_diff):.6f} T")
0412     print(f"  Max absolute error:  {np.max(field_diff):.6f} T")
0413     print(f"  Mean relative error: {np.mean(relative_error):.3f}%")
0414     print(f"  Max relative error:  {np.max(relative_error):.3f}%")
0415 
0416     return {
0417         "points": valid_points,
0418         "analytical": analytical_fields,
0419         "lut": lut_fields,
0420         "field_diff": field_diff,
0421         "relative_error": relative_error,
0422     }
0423 
0424 
0425 def plot_field_comparison(comparison_data, output_dir="toroidal_field_plots"):
0426     """Create field map plots using existing test points only"""
0427     print(f"\n=== Creating Plots (No New Field Evaluations) ===")
0428 
0429     output_path = Path(output_dir)
0430     output_path.mkdir(exist_ok=True)
0431 
0432     points = comparison_data["points"]
0433     analytical_fields = comparison_data["analytical"]
0434     lut_fields = comparison_data.get("lut", None)
0435 
0436     analytical_mag = np.linalg.norm(analytical_fields, axis=1)
0437     lut_mag = np.linalg.norm(lut_fields, axis=1) if lut_fields is not None else None
0438 
0439     print(f"Using {len(points)} existing points - splitting for XY/ZX plots")
0440 
0441     n_half = len(points) // 2
0442 
0443     xy_points = points[:n_half]
0444     xy_analytical_mag = analytical_mag[:n_half]
0445     xy_lut_mag = lut_mag[:n_half] if lut_mag is not None else None
0446 
0447     zx_points = points[n_half:]
0448     zx_analytical_mag = analytical_mag[n_half:]
0449     zx_lut_mag = lut_mag[n_half:] if lut_mag is not None else None
0450 
0451     xy_x, xy_y = xy_points[:, 0], xy_points[:, 1]
0452     xy_sym_x, xy_sym_y, xy_sym_mag = apply_xy_symmetry(xy_x, xy_y, xy_analytical_mag)
0453     xy_lut_sym_mag = (
0454         apply_xy_symmetry(xy_x, xy_y, xy_lut_mag)[2] if xy_lut_mag is not None else None
0455     )
0456 
0457     zx_z, zx_x = zx_points[:, 2], zx_points[:, 0]
0458     zx_sym_z, zx_sym_x, zx_sym_mag = apply_zx_symmetry(zx_z, zx_x, zx_analytical_mag)
0459     zx_lut_sym_mag = (
0460         apply_zx_symmetry(zx_z, zx_x, zx_lut_mag)[2] if zx_lut_mag is not None else None
0461     )
0462 
0463     # Create plots
0464     create_fast_xy_plot(xy_sym_x, xy_sym_y, xy_sym_mag, xy_lut_sym_mag, output_path)
0465     create_fast_zx_plot(zx_sym_z, zx_sym_x, zx_sym_mag, zx_lut_sym_mag, output_path)
0466 
0467     # Create difference plot if LUT data exists
0468     if lut_fields is not None:
0469         create_fast_difference_plot(points, analytical_mag, lut_mag, output_path)
0470 
0471     print(f"Plots completed and saved to {output_dir}/")
0472 
0473 
0474 def apply_xy_symmetry(x, y, values):
0475     """Apply 8-fold rotational symmetry in XY plane"""
0476     angles = np.linspace(0, 2 * np.pi, 8, endpoint=False)
0477 
0478     sym_x = []
0479     sym_y = []
0480     sym_values = []
0481 
0482     for angle in angles:
0483         cos_a, sin_a = np.cos(angle), np.sin(angle)
0484         x_rot = x * cos_a - y * sin_a
0485         y_rot = x * sin_a + y * cos_a
0486 
0487         sym_x.append(x_rot)
0488         sym_y.append(y_rot)
0489         sym_values.append(values)
0490 
0491     return np.concatenate(sym_x), np.concatenate(sym_y), np.concatenate(sym_values)
0492 
0493 
0494 def apply_zx_symmetry(z, x, values):
0495     """Apply 2-fold mirror symmetry in ZX plane"""
0496     sym_z = np.concatenate([z, z])
0497     sym_x = np.concatenate([x, -x])
0498     sym_values = np.concatenate([values, values])
0499 
0500     return sym_z, sym_x, sym_values
0501 
0502 
0503 def create_fast_xy_plot(x, y, analytical_mag, lut_mag, output_path):
0504     """Create XY plot using scatter points only"""
0505     n_plots = 2 if lut_mag is not None else 1
0506     fig, axes = plt.subplots(1, n_plots, figsize=(6 * n_plots, 5))
0507     if n_plots == 1:
0508         axes = [axes]
0509 
0510     # Analytical plot
0511     sc1 = axes[0].scatter(
0512         x,
0513         y,
0514         c=analytical_mag,
0515         cmap="gnuplot2",
0516         norm=LogNorm(vmin=1e-4, vmax=4.1),
0517         s=0.5,
0518         alpha=0.8,
0519     )
0520     axes[0].set_title("Analytical |B| at z=0.20m")
0521     axes[0].set_xlabel("x [m]")
0522     axes[0].set_ylabel("y [m]")
0523     axes[0].set_xlim(-12, 12)
0524     axes[0].set_ylim(-12, 12)
0525     axes[0].set_aspect("equal")
0526     plt.colorbar(sc1, ax=axes[0], label="|B| [T]")
0527 
0528     # LUT plot if available
0529     if lut_mag is not None:
0530         sc2 = axes[1].scatter(
0531             x,
0532             y,
0533             c=lut_mag,
0534             cmap="gnuplot2",
0535             norm=LogNorm(vmin=1e-4, vmax=4.1),
0536             s=0.5,
0537             alpha=0.8,
0538         )
0539         axes[1].set_title("LUT |B| at z=0.20m")
0540         axes[1].set_xlabel("x [m]")
0541         axes[1].set_ylabel("y [m]")
0542         axes[1].set_xlim(-12, 12)
0543         axes[1].set_ylim(-12, 12)
0544         axes[1].set_aspect("equal")
0545         plt.colorbar(sc2, ax=axes[1], label="|B| [T]")
0546 
0547     plt.tight_layout()
0548     plt.savefig(output_path / "field_xy_fast.png", dpi=150, bbox_inches="tight")
0549     plt.close()
0550     print(f"Saved: {output_path}/field_xy_fast.png")
0551 
0552 
0553 def create_fast_zx_plot(z, x, analytical_mag, lut_mag, output_path):
0554     """Create ZX plot using scatter points only"""
0555     n_plots = 2 if lut_mag is not None else 1
0556     fig, axes = plt.subplots(1, n_plots, figsize=(6 * n_plots, 5))
0557     if n_plots == 1:
0558         axes = [axes]
0559 
0560     # Analytical plot
0561     sc1 = axes[0].scatter(
0562         z,
0563         x,
0564         c=analytical_mag,
0565         cmap="gnuplot2",
0566         norm=LogNorm(vmin=1e-4, vmax=4.1),
0567         s=0.5,
0568         alpha=0.8,
0569     )
0570     axes[0].set_title("Analytical |B| at y=0.10m")
0571     axes[0].set_xlabel("z [m]")
0572     axes[0].set_ylabel("x [m]")
0573     axes[0].set_xlim(-20, 20)
0574     axes[0].set_ylim(-12, 12)
0575     axes[0].set_aspect("equal")
0576     plt.colorbar(sc1, ax=axes[0], label="|B| [T]")
0577 
0578     # LUT plot if available
0579     if lut_mag is not None:
0580         sc2 = axes[1].scatter(
0581             z,
0582             x,
0583             c=lut_mag,
0584             cmap="gnuplot2",
0585             norm=LogNorm(vmin=1e-4, vmax=4.1),
0586             s=0.5,
0587             alpha=0.8,
0588         )
0589         axes[1].set_title("LUT |B| at y=0.10m")
0590         axes[1].set_xlabel("z [m]")
0591         axes[1].set_ylabel("x [m]")
0592         axes[1].set_xlim(-20, 20)
0593         axes[1].set_ylim(-12, 12)
0594         axes[1].set_aspect("equal")
0595         plt.colorbar(sc2, ax=axes[1], label="|B| [T]")
0596 
0597     plt.tight_layout()
0598     plt.savefig(output_path / "field_zx_fast.png", dpi=150, bbox_inches="tight")
0599     plt.close()
0600     print(f"Saved: {output_path}/field_zx_fast.png")
0601 
0602 
0603 def create_fast_difference_plot(points, analytical_mag, lut_mag, output_path):
0604     """Create difference analysis using existing data only"""
0605     # Calculate differences
0606     field_diff = np.abs(lut_mag - analytical_mag)
0607     relative_error = np.where(
0608         analytical_mag > 1e-10, field_diff / analytical_mag * 100, 0
0609     )
0610     r = np.sqrt(points[:, 0] ** 2 + points[:, 1] ** 2)
0611 
0612     # Create compact difference plot
0613     fig, axes = plt.subplots(1, 3, figsize=(15, 4))
0614 
0615     # Absolute difference
0616     axes[0].hist(field_diff, bins=30, alpha=0.7, edgecolor="black")
0617     axes[0].set_xlabel("|B_lut - B_analytical| [T]")
0618     axes[0].set_ylabel("Count")
0619     axes[0].set_title("Absolute Difference")
0620     axes[0].grid(True, alpha=0.3)
0621 
0622     # Relative error
0623     axes[1].hist(relative_error, bins=30, alpha=0.7, color="orange", edgecolor="black")
0624     axes[1].set_xlabel("Relative Error [%]")
0625     axes[1].set_ylabel("Count")
0626     axes[1].set_title("Relative Error")
0627     axes[1].grid(True, alpha=0.3)
0628 
0629     # Spatial distribution
0630     sc = axes[2].scatter(
0631         r, points[:, 2], c=relative_error, cmap="plasma", s=1, alpha=0.7
0632     )
0633     axes[2].set_xlabel("r [m]")
0634     axes[2].set_ylabel("z [m]")
0635     axes[2].set_title("Error Distribution")
0636     axes[2].grid(True, alpha=0.3)
0637     plt.colorbar(sc, ax=axes[2], label="Rel. Error [%]")
0638 
0639     plt.tight_layout()
0640     plt.savefig(
0641         output_path / "field_differences_fast.png", dpi=150, bbox_inches="tight"
0642     )
0643     plt.close()
0644     print(f"Saved: {output_path}/field_differences_fast.png")
0645 
0646     # Print summary
0647     print(f"Error Statistics:")
0648     print(f"  Mean absolute error: {np.mean(field_diff):.6f} T")
0649     print(f"  Mean relative error: {np.mean(relative_error):.3f}%")
0650     print(f"  Max relative error:  {np.max(relative_error):.3f}%")
0651 
0652 
0653 def main():
0654     parser = argparse.ArgumentParser(
0655         description="ToroidField vs ToroidFieldMap benchmark"
0656     )
0657     parser.add_argument(
0658         "--resolution",
0659         choices=["low", "medium", "high"],
0660         default="medium",
0661         help="LUT resolution (default: medium)",
0662     )
0663     parser.add_argument(
0664         "--n-points",
0665         type=int,
0666         default=2000,
0667         help="Number of test points for comparison (default: 2000)",
0668     )
0669     parser.add_argument(
0670         "--n-timing",
0671         type=int,
0672         default=5000,
0673         help="Number of points for timing benchmark (default: 5000)",
0674     )
0675     parser.add_argument(
0676         "--output-dir",
0677         default="toroidal_field_plots",
0678         help="Output directory for plots (default: toroidal_field_plots)",
0679     )
0680     parser.add_argument("--no-plots", action="store_true", help="Skip generating plots")
0681     parser.add_argument(
0682         "--force-recreate-lut", action="store_true", help="Force recreation of LUT"
0683     )
0684 
0685     args = parser.parse_args()
0686 
0687     print("=== Toroid Field Map Benchmark ===")
0688     print(f"Configuration:")
0689     print(f"  LUT Resolution: {args.resolution}")
0690     print(f"  Comparison points: {args.n_points}")
0691     print(f"  Timing points: {args.n_timing}")
0692     print(f"  Output directory: {args.output_dir}")
0693     print(f"  Force LUT recreation: {args.force_recreate_lut}")
0694 
0695     try:
0696         # Create analytical field
0697         print(f"\n=== Creating Analytical Field ===")
0698         analytical_field = create_analytical_field()
0699 
0700         # Create/load LUT field
0701         print(f"\n=== Creating/Loading LUT Field ===")
0702         lut_field, lut_params = create_lut_field(
0703             analytical_field, args.resolution, args.force_recreate_lut
0704         )
0705 
0706         # Generate test points
0707         print(f"\n=== Generating Test Points ===")
0708         test_points = generate_test_points(args.n_points)
0709         print(f"Generated {len(test_points)} test points")
0710 
0711         # Benchmark lookup times
0712         timing_results = benchmark_lookup_times(
0713             analytical_field, lut_field, test_points, args.n_timing
0714         )
0715 
0716         # Compare field values
0717         comparison_results = compare_field_values(
0718             analytical_field, lut_field, test_points
0719         )
0720 
0721         # Generate plots
0722         if not args.no_plots:
0723             plot_field_comparison(comparison_results, args.output_dir)
0724         else:
0725             print("Skipping plot generation (--no-plots specified)")
0726 
0727         print(f"\n=== Benchmark Complete ===")
0728         print(f"Results summary:")
0729         print(
0730             f"  Valid comparisons: {len(comparison_results['points'])}/{args.n_points}"
0731         )
0732         print(
0733             f"  Mean relative error: {np.mean(comparison_results['relative_error']):.3f}%"
0734         )
0735         print(f"  Speedup: {timing_results['speedup']:.1f}x")
0736         if not args.no_plots:
0737             print(f"  Plots saved to: {args.output_dir}/")
0738 
0739         return 0
0740 
0741     except Exception as e:
0742         print(f"ERROR: {e}")
0743         import traceback
0744 
0745         traceback.print_exc()
0746         return 1
0747 
0748 
0749 if __name__ == "__main__":
0750     import sys
0751 
0752     sys.exit(main())