feat(seaborn): implement smith-chart-basic

plots/smith-chart-basic/implementations/seaborn.py

@@ -0,0 +1,173 @@
+""" pyplots.ai
+smith-chart-basic: Smith Chart for RF/Impedance
+Library: seaborn 0.13.2 | Python 3.13.11
+Quality: 90/100 | Created: 2026-01-15
+"""
+
+import matplotlib.pyplot as plt
+import numpy as np
+import pandas as pd
+import seaborn as sns
+
+
+# Set seaborn style for better aesthetics
+sns.set_style("whitegrid")
+sns.set_context("talk", font_scale=1.2)
+
+# Reference impedance (ohms)
+z0 = 50
+
+# Generate frequency sweep data (1 GHz to 6 GHz, 50 points)
+np.random.seed(42)
+n_points = 50
+freq_ghz = np.linspace(1, 6, n_points)
+
+# Simulate a realistic impedance locus (antenna-like behavior)
+# Create a spiral pattern that doesn't close on itself (avoids label overlap)
+t = np.linspace(0, 1.8 * np.pi, n_points)
+# Spiral-like pattern typical of antenna impedance vs frequency with drift
+z_real = 50 + 30 * np.sin(t) + 15 * np.cos(2 * t) + 10 * (t / (2 * np.pi))
+z_imag = 40 * np.sin(1.5 * t) + 20 * np.cos(t) - 15 * (t / (2 * np.pi))
+
+# Normalize impedance to reference
+z_norm = (z_real + 1j * z_imag) / z0
+
+# Calculate reflection coefficient (Gamma)
+gamma = (z_norm - 1) / (z_norm + 1)
+gamma_real = gamma.real
+gamma_imag = gamma.imag
+
+# Create figure (square for Smith chart)
+fig, ax = plt.subplots(figsize=(12, 12))
+
+# Draw Smith chart grid
+# Constant resistance circles
+r_values = [0, 0.2, 0.5, 1, 2, 5]
+theta = np.linspace(0, 2 * np.pi, 200)
+
+for r in r_values:
+    # Circle center and radius in Gamma plane
+    center = r / (r + 1)
+    radius = 1 / (r + 1)
+    # Parametric circle
+    circle_x = center + radius * np.cos(theta)
+    circle_y = radius * np.sin(theta)
+    # Clip to unit circle
+    mask = circle_x**2 + circle_y**2 <= 1.001
+    ax.plot(circle_x[mask], circle_y[mask], color="#306998", linewidth=1)
+    # Add r value labels on the real axis (inside unit circle)
+    if r > 0:
+        label_x = r / (r + 1) - 1 / (r + 1) + 0.02  # Left edge of circle
+        if label_x > -0.95:
+            ax.text(label_x, 0.03, f"r={r}", fontsize=10, color="#306998", va="bottom")
+
+# Constant reactance arcs
+x_values = [0.2, 0.5, 1, 2, 5]
+
+for x in x_values:
+    # Positive reactance arc (inductive)
+    center_y = 1 / x
+    radius = 1 / x
+    arc_theta = np.linspace(-np.pi / 2, np.pi / 2, 200)
+    arc_x = 1 + radius * np.cos(arc_theta)
+    arc_y = center_y + radius * np.sin(arc_theta)
+    mask = (arc_x**2 + arc_y**2 <= 1.001) & (arc_x >= -0.001)
+    ax.plot(arc_x[mask], arc_y[mask], color="#D4A017", linewidth=1.5)
+
+    # Negative reactance arc (capacitive)
+    arc_y_neg = -center_y + radius * np.sin(arc_theta)
+    mask_neg = (arc_x**2 + arc_y_neg**2 <= 1.001) & (arc_x >= -0.001)
+    ax.plot(arc_x[mask_neg], arc_y_neg[mask_neg], color="#D4A017", linewidth=1.5)
+
+    # Add x value labels inside the unit circle boundary
+    if x <= 2:
+        label_angle = np.arctan(1 / x)
+        label_x_pos = 0.85 * np.cos(label_angle)
+        label_y_pos = 0.85 * np.sin(label_angle)
+        ax.text(label_x_pos, label_y_pos + 0.03, f"x={x}", fontsize=10, color="#D4A017", va="bottom", ha="center")
+        ax.text(label_x_pos, -label_y_pos - 0.03, f"x=-{x}", fontsize=10, color="#D4A017", va="top", ha="center")
+
+# Draw unit circle (|Gamma| = 1 boundary)
+unit_theta = np.linspace(0, 2 * np.pi, 200)
+ax.plot(np.cos(unit_theta), np.sin(unit_theta), color="#306998", linewidth=2.5)
+
+# Draw horizontal axis (real axis)
+ax.axhline(0, color="#306998", linewidth=1.5, alpha=0.6)
+
+# Create DataFrame for seaborn plotting
+df_locus = pd.DataFrame({"gamma_real": gamma_real, "gamma_imag": gamma_imag, "freq_ghz": freq_ghz})
+
+# Plot impedance locus using seaborn lineplot for the trajectory
+sns.lineplot(
+    data=df_locus, x="gamma_real", y="gamma_imag", color="#E74C3C", linewidth=3, ax=ax, legend=False, sort=False
+)
+
+# Add markers at key frequency points using seaborn scatterplot
+key_indices = [0, n_points // 4, n_points // 2, 3 * n_points // 4, n_points - 1]
+df_markers = df_locus.iloc[key_indices].copy()
+sns.scatterplot(
+    data=df_markers,
+    x="gamma_real",
+    y="gamma_imag",
+    s=200,
+    color="#E74C3C",
+    edgecolor="white",
+    linewidth=2,
+    ax=ax,
+    zorder=10,
+    legend=False,
+)
+
+# Label key frequency points with smart positioning to avoid overlap
+label_offsets = {
+    0: (12, -18),
+    n_points // 4: (15, 12),
+    n_points // 2: (12, -18),
+    3 * n_points // 4: (-60, 10),
+    n_points - 1: (-60, -15),
+}
+
+for idx in key_indices:
+    offset = label_offsets.get(idx, (10, 10))
+    ax.annotate(
+        f"{freq_ghz[idx]:.1f} GHz",
+        (gamma_real[idx], gamma_imag[idx]),
+        textcoords="offset points",
+        xytext=offset,
+        fontsize=14,
+        fontweight="bold",
+        color="#2C3E50",
+    )
+
+# Mark the center (matched condition)
+ax.scatter([0], [0], s=150, color="#27AE60", marker="+", linewidths=3, zorder=10)
+ax.annotate(
+    "Z₀ (50Ω)", (0, 0), textcoords="offset points", xytext=(-40, -20), fontsize=14, color="#27AE60", fontweight="bold"
+)
+
+# Add VSWR circle (|Gamma| = 0.5, VSWR = 3:1)
+vswr_radius = 0.5
+vswr_circle_x = vswr_radius * np.cos(unit_theta)
+vswr_circle_y = vswr_radius * np.sin(unit_theta)
+ax.plot(vswr_circle_x, vswr_circle_y, "--", color="#9B59B6", linewidth=2)
+ax.annotate("VSWR 3:1", (0.35, 0.35), fontsize=12, color="#9B59B6", fontweight="bold")
+
+# Styling
+ax.set_xlim(-1.15, 1.15)
+ax.set_ylim(-1.15, 1.15)
+ax.set_aspect("equal")
+ax.set_xlabel("Real(Γ)", fontsize=20)
+ax.set_ylabel("Imag(Γ)", fontsize=20)
+ax.set_title("smith-chart-basic · seaborn · pyplots.ai", fontsize=24, fontweight="bold", pad=20)
+ax.tick_params(axis="both", labelsize=16)
+ax.grid(False)  # Turn off default grid, we drew our own Smith grid
+
+# Add legend with matching line styles
+ax.plot([], [], color="#306998", linewidth=1, label="Constant R circles")
+ax.plot([], [], color="#D4A017", linewidth=1.5, label="Constant X arcs")
+ax.plot([], [], color="#E74C3C", linewidth=3, label="Impedance locus")
+ax.plot([], [], color="#9B59B6", linewidth=2, linestyle="--", label="VSWR 3:1 circle")
+ax.legend(loc="upper left", fontsize=14, framealpha=0.9)
+
+plt.tight_layout()
+plt.savefig("plot.png", dpi=300, bbox_inches="tight")

plots/smith-chart-basic/metadata/seaborn.yaml

@@ -0,0 +1,216 @@
+library: seaborn
+specification_id: smith-chart-basic
+created: '2026-01-15T21:52:07Z'
+updated: '2026-01-15T22:10:29Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 21047488885
+issue: 3792
+python_version: 3.13.11
+library_version: 0.13.2
+preview_url: https://storage.googleapis.com/pyplots-images/plots/smith-chart-basic/seaborn/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/smith-chart-basic/seaborn/plot_thumb.png
+preview_html: null
+quality_score: 90
+review:
+  strengths:
+  - Excellent Smith chart grid implementation with proper constant R circles and X
+    arcs
+  - Smart frequency label positioning with manual offsets prevents overlap
+  - Complete feature set including VSWR circle and center marking
+  - Professional color scheme with good accessibility
+  - Title format exactly matches specification
+  weaknesses:
+  - Heavy reliance on matplotlib for grid drawing; seaborn only used for final locus
+    overlay
+  - Canvas utilization could be improved (square 12x12 on 16:9 target)
+  image_description: The plot displays a Smith chart for RF/impedance visualization.
+    The chart features a square 12x12 figure with proper aspect ratio. The outer boundary
+    is a dark blue unit circle representing |Γ|=1 (total reflection). Multiple constant
+    resistance circles (r=0.2, 0.5, 1, 2, 5) are drawn in blue, centered along the
+    horizontal real axis. Constant reactance arcs in gold/yellow (x=±0.2, ±0.5, ±1,
+    ±2) curve from the right edge. A red impedance locus curve traces the frequency
+    sweep from 1.0 GHz to 6.0 GHz, with five key frequency markers (1.0, 3.2, 4.8,
+    3.6, 6.0 GHz) labeled in dark blue text. A dashed purple VSWR 3:1 circle (|Γ|=0.5)
+    is included. The center point is marked with a green '+' symbol and labeled 'Z₀
+    (50Ω)'. A legend in the upper left shows all four element types. Axes are labeled
+    'Real(Γ)' and 'Imag(Γ)' with appropriate font sizes.
+  criteria_checklist:
+    visual_quality:
+      score: 36
+      max: 40
+      items:
+      - id: VQ-01
+        name: Text Legibility
+        score: 10
+        max: 10
+        passed: true
+        comment: Title at 24pt, axis labels at 20pt, tick labels at 16pt, frequency
+          annotations at 14pt bold - all clearly readable
+      - id: VQ-02
+        name: No Overlap
+        score: 8
+        max: 8
+        passed: true
+        comment: Smart label positioning with custom offsets prevents all text overlap
+      - id: VQ-03
+        name: Element Visibility
+        score: 6
+        max: 8
+        passed: true
+        comment: Impedance locus clearly visible with linewidth=3, markers s=200;
+          grid lines could be slightly thinner
+      - id: VQ-04
+        name: Color Accessibility
+        score: 5
+        max: 5
+        passed: true
+        comment: Blue/gold/red/purple color scheme is colorblind-safe, high contrast
+      - id: VQ-05
+        name: Layout Balance
+        score: 3
+        max: 5
+        passed: true
+        comment: Square 12x12 figure with xlim/ylim ±1.15 provides good margins, moderate
+          canvas utilization
+      - id: VQ-06
+        name: Axis Labels
+        score: 2
+        max: 2
+        passed: true
+        comment: Real(Γ) and Imag(Γ) are descriptive for Smith chart context
+      - id: VQ-07
+        name: Grid & Legend
+        score: 2
+        max: 2
+        passed: true
+        comment: Default grid disabled, custom Smith grid drawn with appropriate line
+          weights, legend well-placed
+    spec_compliance:
+      score: 25
+      max: 25
+      items:
+      - id: SC-01
+        name: Plot Type
+        score: 8
+        max: 8
+        passed: true
+        comment: Correct Smith chart with constant resistance circles and reactance
+          arcs
+      - id: SC-02
+        name: Data Mapping
+        score: 5
+        max: 5
+        passed: true
+        comment: Impedance correctly normalized to Z₀=50Ω, gamma calculated properly
+      - id: SC-03
+        name: Required Features
+        score: 5
+        max: 5
+        passed: true
+        comment: 'All spec features: grid circles/arcs, impedance locus, frequency
+          labels, VSWR circle, center marking'
+      - id: SC-04
+        name: Data Range
+        score: 3
+        max: 3
+        passed: true
+        comment: Unit circle boundary properly shown with ±1.15 limits
+      - id: SC-05
+        name: Legend Accuracy
+        score: 2
+        max: 2
+        passed: true
+        comment: Legend correctly identifies all four element types
+      - id: SC-06
+        name: Title Format
+        score: 2
+        max: 2
+        passed: true
+        comment: 'Uses exact format: smith-chart-basic · seaborn · pyplots.ai'
+    data_quality:
+      score: 18
+      max: 20
+      items:
+      - id: DQ-01
+        name: Feature Coverage
+        score: 7
+        max: 8
+        passed: true
+        comment: Shows spiral impedance locus typical of antenna behavior, crosses
+          multiple grid regions
+      - id: DQ-02
+        name: Realistic Context
+        score: 7
+        max: 7
+        passed: true
+        comment: RF antenna impedance sweep 1-6 GHz is a realistic VNA measurement
+          scenario
+      - id: DQ-03
+        name: Appropriate Scale
+        score: 4
+        max: 5
+        passed: true
+        comment: Z₀=50Ω standard, impedance values reasonable for antenna (30-80Ω
+          range)
+    code_quality:
+      score: 8
+      max: 10
+      items:
+      - id: CQ-01
+        name: KISS Structure
+        score: 3
+        max: 3
+        passed: true
+        comment: 'Linear flow: imports → data → Smith grid → seaborn plots → styling
+          → save'
+      - id: CQ-02
+        name: Reproducibility
+        score: 3
+        max: 3
+        passed: true
+        comment: np.random.seed(42) set
+      - id: CQ-03
+        name: Clean Imports
+        score: 0
+        max: 2
+        passed: false
+        comment: sns and pd imports present but seaborn barely used beyond lineplot/scatterplot
+      - id: CQ-04
+        name: No Deprecated API
+        score: 1
+        max: 1
+        passed: true
+        comment: All APIs current
+      - id: CQ-05
+        name: Output Correct
+        score: 1
+        max: 1
+        passed: true
+        comment: Saves as plot.png with dpi=300
+    library_features:
+      score: 3
+      max: 5
+      items:
+      - id: LF-01
+        name: Distinctive Features
+        score: 3
+        max: 5
+        passed: true
+        comment: Uses sns.lineplot and sns.scatterplot with DataFrames, sns.set_style/set_context
+          for theming, but heavy matplotlib reliance for grid drawing
+  verdict: APPROVED
+impl_tags:
+  dependencies: []
+  techniques:
+  - annotations
+  - patches
+  - manual-ticks
+  - custom-legend
+  patterns:
+  - data-generation
+  - iteration-over-groups
+  - explicit-figure
+  dataprep: []
+  styling:
+  - edge-highlighting
+  - grid-styling