Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/scipy/special/_precompute/struve_convergence.py

@@ -0,0 +1,120 @@
+"""
+Convergence regions of the expansions used in ``struve.c``
+
+Note that for v >> z both functions tend rapidly to 0,
+and for v << -z, they tend to infinity.
+
+The floating-point functions over/underflow in the lower left and right
+corners of the figure.
+
+
+Figure legend
+=============
+
+Red region
+    Power series is close (1e-12) to the mpmath result
+
+Blue region
+    Asymptotic series is close to the mpmath result
+
+Green region
+    Bessel series is close to the mpmath result
+
+Dotted colored lines
+    Boundaries of the regions
+
+Solid colored lines
+    Boundaries estimated by the routine itself. These will be used
+    for determining which of the results to use.
+
+Black dashed line
+    The line z = 0.7*|v| + 12
+
+"""
+import numpy as np
+import matplotlib.pyplot as plt  # type: ignore[import]
+
+import mpmath  # type: ignore[import]
+
+
+def err_metric(a, b, atol=1e-290):
+    m = abs(a - b) / (atol + abs(b))
+    m[np.isinf(b) & (a == b)] = 0
+    return m
+
+
+def do_plot(is_h=True):
+    from scipy.special._ufuncs import (_struve_power_series,
+                                       _struve_asymp_large_z,
+                                       _struve_bessel_series)
+
+    vs = np.linspace(-1000, 1000, 91)
+    zs = np.sort(np.r_[1e-5, 1.0, np.linspace(0, 700, 91)[1:]])
+
+    rp = _struve_power_series(vs[:,None], zs[None,:], is_h)
+    ra = _struve_asymp_large_z(vs[:,None], zs[None,:], is_h)
+    rb = _struve_bessel_series(vs[:,None], zs[None,:], is_h)
+
+    mpmath.mp.dps = 50
+    if is_h:
+        sh = lambda v, z: float(mpmath.struveh(mpmath.mpf(v), mpmath.mpf(z)))
+    else:
+        sh = lambda v, z: float(mpmath.struvel(mpmath.mpf(v), mpmath.mpf(z)))
+    ex = np.vectorize(sh, otypes='d')(vs[:,None], zs[None,:])
+
+    err_a = err_metric(ra[0], ex) + 1e-300
+    err_p = err_metric(rp[0], ex) + 1e-300
+    err_b = err_metric(rb[0], ex) + 1e-300
+
+    err_est_a = abs(ra[1]/ra[0])
+    err_est_p = abs(rp[1]/rp[0])
+    err_est_b = abs(rb[1]/rb[0])
+
+    z_cutoff = 0.7*abs(vs) + 12
+
+    levels = [-1000, -12]
+
+    plt.cla()
+
+    plt.hold(1)
+    plt.contourf(vs, zs, np.log10(err_p).T, levels=levels, colors=['r', 'r'], alpha=0.1)
+    plt.contourf(vs, zs, np.log10(err_a).T, levels=levels, colors=['b', 'b'], alpha=0.1)
+    plt.contourf(vs, zs, np.log10(err_b).T, levels=levels, colors=['g', 'g'], alpha=0.1)
+
+    plt.contour(vs, zs, np.log10(err_p).T, levels=levels, colors=['r', 'r'], linestyles=[':', ':'])
+    plt.contour(vs, zs, np.log10(err_a).T, levels=levels, colors=['b', 'b'], linestyles=[':', ':'])
+    plt.contour(vs, zs, np.log10(err_b).T, levels=levels, colors=['g', 'g'], linestyles=[':', ':'])
+
+    lp = plt.contour(vs, zs, np.log10(err_est_p).T, levels=levels, colors=['r', 'r'], linestyles=['-', '-'])
+    la = plt.contour(vs, zs, np.log10(err_est_a).T, levels=levels, colors=['b', 'b'], linestyles=['-', '-'])
+    lb = plt.contour(vs, zs, np.log10(err_est_b).T, levels=levels, colors=['g', 'g'], linestyles=['-', '-'])
+
+    plt.clabel(lp, fmt={-1000: 'P', -12: 'P'})
+    plt.clabel(la, fmt={-1000: 'A', -12: 'A'})
+    plt.clabel(lb, fmt={-1000: 'B', -12: 'B'})
+
+    plt.plot(vs, z_cutoff, 'k--')
+
+    plt.xlim(vs.min(), vs.max())
+    plt.ylim(zs.min(), zs.max())
+
+    plt.xlabel('v')
+    plt.ylabel('z')
+
+
+def main():
+    plt.clf()
+    plt.subplot(121)
+    do_plot(True)
+    plt.title('Struve H')
+
+    plt.subplot(122)
+    do_plot(False)
+    plt.title('Struve L')
+
+    plt.savefig('struve_convergence.png')
+    plt.show()
+
+
+if __name__ == "__main__":
+    main()