1 files changed, 98 insertions, 0 deletions
diff --git a/buch/papers/laguerre/scripts/laguerre_poly.py b/buch/papers/laguerre/scripts/laguerre_poly.py
new file mode 100644
index 0000000..954a0b1
--- /dev/null
+++ b/buch/papers/laguerre/scripts/laguerre_poly.py
@@ -0,0 +1,98 @@
+import numpy as np
+
+
+def get_ticks(start, end, step=1):
+    ticks = np.arange(start, end, step)
+    return ticks[ticks != 0]
+
+
+if __name__ == "__main__":
+    import os
+    from pathlib import Path
+
+    import matplotlib.pyplot as plt
+    import scipy.special as ss
+
+    N = 1000
+    step = 5
+    t = np.linspace(-1.05, 10.5, N)[:, None]
+    root = str(Path(__file__).parent)
+    img_path = f"{root}/../images"
+    os.makedirs(img_path, exist_ok=True)
+
+    # fig = plt.figure(num=1, clear=True, tight_layout=True, figsize=(5.5, 3.7))
+    # ax = fig.add_subplot(axes_class=AxesZero)
+    fig, ax = plt.subplots(num=1, clear=True, constrained_layout=True, figsize=(6, 4))
+    for n in np.arange(0, 8):
+        k = np.arange(0, n + 1)[None]
+        L = np.sum((-1) ** k * ss.binom(n, k) / ss.factorial(k) * t ** k, -1)
+        ax.plot(t, L, label=f"$n={n}$")
+
+    ax.set_xticks(get_ticks(int(t[0]), t[-1]), minor=True)
+    ax.set_xticks(get_ticks(0, t[-1], step))
+    ax.set_xlim(t[0], t[-1] + 0.1 * (t[1] - t[0]))
+    ax.set_xlabel(r"$x$", x=1.0, labelpad=-10, rotation=0, fontsize="large")
+
+    ylim = 13
+    ax.set_yticks(np.arange(-ylim, ylim), minor=True)
+    ax.set_yticks(np.arange(-step * (ylim // step), ylim, step))
+    ax.set_ylim(-ylim, ylim)
+    ax.set_ylabel(r"$y$", y=0.95, labelpad=-18, rotation=0, fontsize="large")
+
+    ax.legend(ncol=2, loc=(0.125, 0.01), fontsize="large")
+
+    # set the x-spine
+    ax.spines[["left", "bottom"]].set_position("zero")
+    ax.spines[["right", "top"]].set_visible(False)
+    ax.xaxis.set_ticks_position("bottom")
+    hlx = 0.4
+    dx = t[-1, 0] - t[0, 0]
+    dy = 2 * ylim
+    hly = dy / dx * hlx
+    dps = fig.dpi_scale_trans.inverted()
+    bbox = ax.get_window_extent().transformed(dps)
+    width, height = bbox.width, bbox.height
+
+    # manual arrowhead width and length
+    hw = 1.0 / 60.0 * dy
+    hl = 1.0 / 30.0 * dx
+    lw = 0.5  # axis line width
+    ohg = 0.0  # arrow overhang
+
+    # compute matching arrowhead length and width
+    yhw = hw / dy * dx * height / width
+    yhl = hl / dx * dy * width / height
+
+    # draw x and y axis
+    ax.arrow(
+        t[-1, 0] - hl,
+        0,
+        hl,
+        0.0,
+        fc="k",
+        ec="k",
+        lw=lw,
+        head_width=hw,
+        head_length=hl,
+        overhang=ohg,
+        length_includes_head=True,
+        clip_on=False,
+    )
+
+    ax.arrow(
+        0,
+        ylim - yhl,
+        0.0,
+        yhl,
+        fc="k",
+        ec="k",
+        lw=lw,
+        head_width=yhw,
+        head_length=yhl,
+        overhang=ohg,
+        length_includes_head=True,
+        clip_on=False,
+    )
+
+    fig.savefig(f"{img_path}/laguerre_poly.pgf")
+    # plt.show()