|
| 1 | +import numpy as np |
| 2 | +from quaddtype import QuadPrecDType, QuadPrecision |
| 3 | +import matplotlib.pyplot as plt |
| 4 | + |
| 5 | + |
| 6 | +def get_color(t, interior_t): |
| 7 | + epsilon = QuadPrecision("1e-10") |
| 8 | + |
| 9 | + if abs(t - QuadPrecision(1.0)) < epsilon: |
| 10 | + value = int(255 * interior_t) |
| 11 | + return np.array([value, value, value], dtype=np.uint8) |
| 12 | + |
| 13 | + t = np.power(t, 0.5) |
| 14 | + t = np.mod(t * 20, 1.0) |
| 15 | + |
| 16 | + if t < 0.16: |
| 17 | + return np.array([0, int(255 * (t / 0.16)), int(128 + 127 * (t / 0.16))], dtype=np.uint8) |
| 18 | + elif t < 0.33: |
| 19 | + return np.array([0, 255, int(255 * (1 - (t - 0.16) / 0.17))], dtype=np.uint8) |
| 20 | + elif t < 0.5: |
| 21 | + return np.array([int(255 * ((t - 0.33) / 0.17)), 255, 0], dtype=np.uint8) |
| 22 | + elif t < 0.66: |
| 23 | + return np.array([255, int(255 * (1 - (t - 0.5) / 0.16)), 0], dtype=np.uint8) |
| 24 | + elif t < 0.83: |
| 25 | + return np.array([255, 0, int(255 * ((t - 0.66) / 0.17))], dtype=np.uint8) |
| 26 | + else: |
| 27 | + return np.array([int(255 * (1 - (t - 0.83) / 0.17)), 0, int(128 * ((t - 0.83) / 0.17))], dtype=np.uint8) |
| 28 | + |
| 29 | + |
| 30 | +def iterate_and_compute_derivatives(cr, ci, max_iter): |
| 31 | + zr, zi = 0.0, 0.0 |
| 32 | + dzr, dzi = 1.0, 0.0 |
| 33 | + dcr, dci = 0.0, 0.0 |
| 34 | + dzdzr, dzdzi = 0.0, 0.0 |
| 35 | + |
| 36 | + for _ in range(max_iter): |
| 37 | + dzdzr_new = 2 * (zr * dzdzr - zi * dzdzi + dzr * dzr - dzi * dzi) |
| 38 | + dzdzi_new = 2 * (zr * dzdzi + zi * dzdzr + 2 * dzr * dzi) |
| 39 | + dzr_new = 2 * (zr * dzr - zi * dzi) + dcr |
| 40 | + dzi_new = 2 * (zr * dzi + zi * dzr) + dci |
| 41 | + zr_new = zr * zr - zi * zi + cr |
| 42 | + zi_new = 2 * zr * zi + ci |
| 43 | + |
| 44 | + dzdzr, dzdzi = dzdzr_new, dzdzi_new |
| 45 | + dzr, dzi = dzr_new, dzi_new |
| 46 | + zr, zi = zr_new, zi_new |
| 47 | + dcr, dci = 1.0, 0.0 |
| 48 | + |
| 49 | + return zr, zi, dzr, dzi, dcr, dci, dzdzr, dzdzi |
| 50 | + |
| 51 | + |
| 52 | +def estimate_interior_distance(cr, ci, max_iter): |
| 53 | + zr, zi, dzr, dzi, dcr, dci, dzdzr, dzdzi = iterate_and_compute_derivatives( |
| 54 | + cr, ci, max_iter) |
| 55 | + |
| 56 | + dz_abs_sq = dzr * dzr + dzi * dzi |
| 57 | + numerator = 1 - dz_abs_sq |
| 58 | + |
| 59 | + denominator = np.abs((dcr * dzr + dci * dzi) + |
| 60 | + (dzdzr * zr + dzdzi * zi) * dcr) |
| 61 | + |
| 62 | + return numerator / denominator |
| 63 | + |
| 64 | + |
| 65 | +def mandelbrot(cr, ci, max_iter, radius2): |
| 66 | + zr, zi = QuadPrecision(0.0), QuadPrecision(0.0) |
| 67 | + for i in range(max_iter): |
| 68 | + zr_new = zr * zr - zi * zi + cr |
| 69 | + zi_new = QuadPrecision(2) * zr * zi + ci |
| 70 | + zr, zi = zr_new, zi_new |
| 71 | + if zr * zr + zi * zi > radius2: |
| 72 | + log_zn = np.log(zr * zr + zi * zi) / QuadPrecision(2) |
| 73 | + nu = np.log(log_zn / np.log(QuadPrecision(2))) / \ |
| 74 | + np.log(QuadPrecision(2)) |
| 75 | + return i + QuadPrecision(1) - nu, zr, zi |
| 76 | + return max_iter, zr, zi |
| 77 | + |
| 78 | + |
| 79 | +def mandelbrot_set(width, height, max_iter, center_r, center_i, zoom): |
| 80 | + radius = QuadPrecision(2.0) |
| 81 | + radius2 = radius * radius |
| 82 | + zoom = 1 / zoom |
| 83 | + |
| 84 | + x = np.linspace(np.float64(center_r - radius / zoom), |
| 85 | + np.float64(center_r + radius / zoom), |
| 86 | + width) |
| 87 | + y = np.linspace(np.float64(center_i - radius / zoom), |
| 88 | + np.float64(center_i + radius / zoom), |
| 89 | + height) |
| 90 | + cr, ci = np.meshgrid(x, y) |
| 91 | + |
| 92 | + smooth_iter = np.zeros((height, width), dtype=QuadPrecDType) |
| 93 | + final_zr = np.zeros((height, width), dtype=QuadPrecDType) |
| 94 | + final_zi = np.zeros((height, width), dtype=QuadPrecDType) |
| 95 | + |
| 96 | + for i in range(height): |
| 97 | + for j in range(width): |
| 98 | + smooth_iter[i, j], final_zr[i, j], final_zi[i, j] = mandelbrot( |
| 99 | + cr[i, j], ci[i, j], max_iter, radius2) |
| 100 | + |
| 101 | + img = np.zeros((height, width, 3), dtype=np.uint8) |
| 102 | + |
| 103 | + interior_mask = smooth_iter == QuadPrecision(max_iter) |
| 104 | + interior_cr = cr[interior_mask] |
| 105 | + interior_ci = ci[interior_mask] |
| 106 | + interior_distance = np.array([estimate_interior_distance( |
| 107 | + cr, ci, max_iter) for cr, ci in zip(interior_cr, interior_ci)]) |
| 108 | + interior_t = (interior_distance - |
| 109 | + np.floor(interior_distance)).astype(np.float64) |
| 110 | + |
| 111 | + exterior_mask = ~interior_mask |
| 112 | + t = smooth_iter[exterior_mask] / QuadPrecision(max_iter) |
| 113 | + |
| 114 | + interior_colors = np.array( |
| 115 | + [get_color(QuadPrecision(1.0), t) for t in interior_t]) |
| 116 | + exterior_colors = np.array([get_color(t, QuadPrecision(0.0)) for t in t]) |
| 117 | + |
| 118 | + img[interior_mask] = interior_colors |
| 119 | + img[exterior_mask] = exterior_colors |
| 120 | + |
| 121 | + return img |
| 122 | + |
| 123 | + |
| 124 | +def plot_mandelbrot(width, height, max_iter, center_r, center_i, zoom): |
| 125 | + center_rq = QuadPrecision(center_r) |
| 126 | + center_iq = QuadPrecision(center_i) |
| 127 | + zoom_q = QuadPrecision(zoom) |
| 128 | + |
| 129 | + img_array = mandelbrot_set( |
| 130 | + width, height, max_iter, center_rq, center_iq, zoom_q) |
| 131 | + |
| 132 | + plt.figure(figsize=(10, 10)) |
| 133 | + plt.imshow(img_array) |
| 134 | + plt.axis('off') |
| 135 | + plt.title( |
| 136 | + f'Mandelbrot Set (zoom: {zoom}, center: {center_r} + {center_i}i, iterations: {max_iter}, dtype: numpy.float64)') |
| 137 | + plt.show() |
| 138 | + |
| 139 | + |
| 140 | +if __name__ == "__main__": |
| 141 | + width = 800 |
| 142 | + height = 800 |
| 143 | + max_iter = 1000 |
| 144 | + center_r = -0.75 |
| 145 | + center_i = 0.0 |
| 146 | + zoom = 1.0 |
| 147 | + |
| 148 | + plot_mandelbrot(width, height, max_iter, center_r, center_i, zoom) |
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