"""Compare integer radicals and the two prime-factor counts. Run from _media: python3 ../prime-factor-multiplicity-comparison.py The PNG basename is written to the current working directory. Tested with Python 3.14.4, NumPy 2.3.5 and Matplotlib 3.10.7. Dependencies are documented in the repository's pyproject.toml. """ from pathlib import Path import matplotlib matplotlib.use("Agg") import matplotlib.pyplot as plt from matplotlib.patches import Rectangle import numpy as np def main(): primes = np.array([2, 3, 5]) exponents = np.array([[3, 2, 0], [1, 1, 1], [5, 0, 0], [2, 2, 0]]) numbers = np.prod(primes ** exponents, axis=1) radicals = np.prod(np.where(exponents > 0, primes, 1), axis=1) distinct = np.count_nonzero(exponents, axis=1) total = exponents.sum(axis=1) labels = [r"$72=2^3\cdot3^2$", r"$30=2\cdot3\cdot5$", r"$32=2^5$", r"$36=2^2\cdot3^2$"] colors = ["#256796", "#aa551b", "#27804c"] plt.rcParams.update({"font.size": 12}) fig, (blocks, table_ax) = plt.subplots( 1, 2, figsize=(9.0, 5.6), dpi=120, gridspec_kw={"width_ratios": [1.65, 1]}, facecolor="white") fig.subplots_adjust(left=0.03, right=0.98, bottom=0.25, top=0.80, wspace=0.10) blocks.set(xlim=(-2.8, 6.7), ylim=(-0.7, 3.7)) blocks.axis("off") blocks.set_title("Prime occurrences, grouped by prime", fontsize=12, pad=12) for row, (powers, label) in enumerate(zip(exponents, labels)): y = 3 - row blocks.text(-2.65, y, label, va="center", fontsize=13) x = 0.0 for prime, exponent, color in zip(primes, powers, colors): if exponent == 0: continue for _ in range(int(exponent)): blocks.add_patch(Rectangle((x, y - 0.29), 0.73, 0.58, facecolor=color, edgecolor="white", linewidth=1.5)) blocks.text(x + 0.365, y, str(prime), color="white", ha="center", va="center", weight="bold", fontsize=13) x += 0.80 x += 0.28 table_ax.axis("off") table_ax.set_title("Three summaries", fontsize=12, pad=12) cells = np.column_stack([numbers, radicals, distinct, total]).astype(str) table = table_ax.table( cellText=cells, colLabels=[r"$n$", r"$\mathrm{rad}(n)$", r"$\omega(n)$", r"$\Omega(n)$"], colWidths=[0.18, 0.33, 0.245, 0.245], cellLoc="center", bbox=[0.0, 0.055, 1.0, 0.89]) table.auto_set_font_size(False) table.set_fontsize(12) for (row, _), cell in table.get_celld().items(): cell.set_edgecolor("#d4d4d4") cell.set_facecolor("#eef2f5" if row == 0 else "white") if row == 0: cell.get_text().set_weight("bold") fig.suptitle("Keep the primes, count the groups, or count every copy", fontsize=16, y=0.96) fig.text(0.5, 0.18, r"$\mathrm{rad}$: multiply one prime per group " r"$\omega$: count groups $\Omega$: count boxes", ha="center", fontsize=12) fig.text(0.5, 0.105, "72 and 36 share their primes; 72 and 32 share their total count.", ha="center", fontsize=12) fig.text(0.5, 0.045, r"No prime boxes for 1: $\mathrm{rad}(1)=1$, $\omega(1)=\Omega(1)=0$.", ha="center", fontsize=12) fig.savefig(Path.cwd() / "prime-factor-multiplicity-comparison.png", facecolor="white", transparent=False) plt.close(fig) if __name__ == "__main__": main()