|
| 1 | +{ |
| 2 | + "cells": [ |
| 3 | + { |
| 4 | + "cell_type": "markdown", |
| 5 | + "id": "c8dd1a63-cf7d-4a28-878b-54167df286c1", |
| 6 | + "metadata": {}, |
| 7 | + "source": [ |
| 8 | + "## Customing transformations and interpolations\n", |
| 9 | + "\n", |
| 10 | + "The transformations and interpolation frameworks are intentionally written in an open-ended manner so that you can write your own transformations for your particular data. \n", |
| 11 | + "\n", |
| 12 | + "To write your own transformer class, you should inherit from the abstract `Transformer` and implement a number of methods: \n", |
| 13 | + "\n", |
| 14 | + "* `_calculate_transformed`\n", |
| 15 | + "* `_calculate_native`\n", |
| 16 | + "* `calculate_transformed_bbox`\n", |
| 17 | + "\n", |
| 18 | + "Additionally, the base `Transformer` allows arbitary coordinate names, so it is often helpful to override the `__init__` method in order to specify the expected coordinate names. \n", |
| 19 | + "\n", |
| 20 | + "So to get started, let's define a transformer to go from an arbitrary 2d coordinate system with coordinate axes `b` and `c` to 3D cartesian coordinates and being by overriding `__init__`:\n", |
| 21 | + "\n", |
| 22 | + "```python\n", |
| 23 | + "from yt_xarray.transformations import Transformer\n", |
| 24 | + "\n", |
| 25 | + "class MyTransformer(Transformer):\n", |
| 26 | + "\n", |
| 27 | + " def __init__(self): \n", |
| 28 | + " native_coords = ('b', 'c')\n", |
| 29 | + " transformed_coords = ('x', 'y', 'z')\n", |
| 30 | + " super().__init__(native_coords, transformed_coords)\n", |
| 31 | + "```\n", |
| 32 | + "\n", |
| 33 | + "\n", |
| 34 | + "Now let's define `_calculate_transformed` to describe the function x, y, z = f(b, c). `_calculate_transformed` must conform to a number of requirmements. First, `_calculate_transformed` must accept a `**coords` argument. That `**coords` keyword dictionary is **guaranteed** to have entries keyed by the `native_coords` tuple (validation is taken care by methods in the abstract class). `_calculate_transformed` must then return the coordinates in the transformed coordinate system. We'll do something competely arbitrary here... \n", |
| 35 | + "\n", |
| 36 | + "```python\n", |
| 37 | + "\n", |
| 38 | + " def _calculate_transformed(self, **coords):\n", |
| 39 | + " b = coords['b'] \n", |
| 40 | + " c = coords['c'] \n", |
| 41 | + " x = b * 2 \n", |
| 42 | + " y = c * 4\n", |
| 43 | + " z = np.sqrt(x**2 + y**2) \n", |
| 44 | + " return x, y, z\n", |
| 45 | + "```\n", |
| 46 | + "\n", |
| 47 | + "Now, add on `_calculate_native`, which in this exmaple will go from (x, y, z) to (b, c). \n", |
| 48 | + "\n", |
| 49 | + "```python \n", |
| 50 | + " \n", |
| 51 | + " def _calculate_native(self, **coords):\n", |
| 52 | + " x = coords['x']\n", |
| 53 | + " y = coords['y'] \n", |
| 54 | + " \n", |
| 55 | + " b = x / 2.0 \n", |
| 56 | + " c = y / 4.0 \n", |
| 57 | + " return b, c \n", |
| 58 | + "```\n", |
| 59 | + "\n", |
| 60 | + "And finally, `calculate_transformed_bbox` must provide a method for calculating the bounding range of coordinates in the transformed coordinate given bounds in the native coordinate system. In this arbitrary coordinate system, we can simply call the method's `to_transformed` at the bounds of the native range to get the bounding box in the transformed system: \n", |
| 61 | + "\n", |
| 62 | + "``` python\n", |
| 63 | + " def calculate_transformed_bbox(self, bbox_dict):\n", |
| 64 | + " b_min_max = bbox_dict['b']\n", |
| 65 | + " c_min_max = bbox_dict['c']\n", |
| 66 | + "\n", |
| 67 | + " xmin, ymin, zmin = self.to_transformed(b=b_min_max[0], \n", |
| 68 | + " c=c_min_max[0])\n", |
| 69 | + " xmax, ymax, zmax = self.to_transformed(b=b_min_max[1], \n", |
| 70 | + " c=c_min_max[1])\n", |
| 71 | + "```\n", |
| 72 | + "\n", |
| 73 | + "Putting it all together:\n" |
| 74 | + ] |
| 75 | + }, |
| 76 | + { |
| 77 | + "cell_type": "code", |
| 78 | + "execution_count": 4, |
| 79 | + "id": "2add05c6-e95e-4504-a3cb-85c6d3720968", |
| 80 | + "metadata": {}, |
| 81 | + "outputs": [], |
| 82 | + "source": [ |
| 83 | + "import numpy as np \n", |
| 84 | + "from yt_xarray.transformations import Transformer\n", |
| 85 | + "\n", |
| 86 | + "class MyTransformer(Transformer):\n", |
| 87 | + "\n", |
| 88 | + " def __init__(self): \n", |
| 89 | + " native_coords = ('b', 'c')\n", |
| 90 | + " transformed_coords = ('x', 'y', 'z')\n", |
| 91 | + " super().__init__(native_coords, transformed_coords)\n", |
| 92 | + "\n", |
| 93 | + " def _calculate_transformed(self, **coords):\n", |
| 94 | + " b = coords['b'] \n", |
| 95 | + " c = coords['c'] \n", |
| 96 | + " x = b * 2. \n", |
| 97 | + " y = c * 4.\n", |
| 98 | + " z = np.sqrt(x**2 + y**2) \n", |
| 99 | + " return x, y, z\n", |
| 100 | + "\n", |
| 101 | + " def _calculate_native(self, **coords):\n", |
| 102 | + " x = coords['x']\n", |
| 103 | + " y = coords['y'] \n", |
| 104 | + " \n", |
| 105 | + " b = x / 2.0 \n", |
| 106 | + " c = y / 4.0 \n", |
| 107 | + " return b, c \n", |
| 108 | + "\n", |
| 109 | + " def calculate_transformed_bbox(self, bbox_dict):\n", |
| 110 | + " b_min_max = bbox_dict['b']\n", |
| 111 | + " c_min_max = bbox_dict['c']\n", |
| 112 | + "\n", |
| 113 | + " xmin, ymin, zmin = self.to_transformed(b=b_min_max[0], \n", |
| 114 | + " c=c_min_max[0])\n", |
| 115 | + " xmax, ymax, zmax = self.to_transformed(b=b_min_max[1], \n", |
| 116 | + " c=c_min_max[1])" |
| 117 | + ] |
| 118 | + }, |
| 119 | + { |
| 120 | + "cell_type": "markdown", |
| 121 | + "id": "06eed913-00b3-4440-a166-04fd446f61da", |
| 122 | + "metadata": {}, |
| 123 | + "source": [ |
| 124 | + "our transformer is now available to use! " |
| 125 | + ] |
| 126 | + }, |
| 127 | + { |
| 128 | + "cell_type": "code", |
| 129 | + "execution_count": 5, |
| 130 | + "id": "bf9f528b-2bf4-45c6-81a9-a92bb7462608", |
| 131 | + "metadata": {}, |
| 132 | + "outputs": [], |
| 133 | + "source": [ |
| 134 | + "mtf = MyTransformer()" |
| 135 | + ] |
| 136 | + }, |
| 137 | + { |
| 138 | + "cell_type": "code", |
| 139 | + "execution_count": 6, |
| 140 | + "id": "c764bf56-b3c4-434f-9cb6-c0ca0113736c", |
| 141 | + "metadata": {}, |
| 142 | + "outputs": [ |
| 143 | + { |
| 144 | + "data": { |
| 145 | + "text/plain": [ |
| 146 | + "(0.0, 0.0, 0.0)" |
| 147 | + ] |
| 148 | + }, |
| 149 | + "execution_count": 6, |
| 150 | + "metadata": {}, |
| 151 | + "output_type": "execute_result" |
| 152 | + } |
| 153 | + ], |
| 154 | + "source": [ |
| 155 | + "x, y, z = mtf.to_transformed(b=0,c=0)\n", |
| 156 | + "x, y, z" |
| 157 | + ] |
| 158 | + }, |
| 159 | + { |
| 160 | + "cell_type": "code", |
| 161 | + "execution_count": 7, |
| 162 | + "id": "a5654087-b37a-460e-9034-e0792cd3a167", |
| 163 | + "metadata": {}, |
| 164 | + "outputs": [ |
| 165 | + { |
| 166 | + "data": { |
| 167 | + "text/plain": [ |
| 168 | + "(0.0, 0.0)" |
| 169 | + ] |
| 170 | + }, |
| 171 | + "execution_count": 7, |
| 172 | + "metadata": {}, |
| 173 | + "output_type": "execute_result" |
| 174 | + } |
| 175 | + ], |
| 176 | + "source": [ |
| 177 | + "mtf.to_native(x=x, y=y, z=z)" |
| 178 | + ] |
| 179 | + }, |
| 180 | + { |
| 181 | + "cell_type": "code", |
| 182 | + "execution_count": 8, |
| 183 | + "id": "f4933f94-6ab2-4827-8192-59363f116327", |
| 184 | + "metadata": {}, |
| 185 | + "outputs": [ |
| 186 | + { |
| 187 | + "name": "stdout", |
| 188 | + "output_type": "stream", |
| 189 | + "text": [ |
| 190 | + "1.0 40.0 40.01249804748511\n" |
| 191 | + ] |
| 192 | + }, |
| 193 | + { |
| 194 | + "data": { |
| 195 | + "text/plain": [ |
| 196 | + "(0.5, 10.0)" |
| 197 | + ] |
| 198 | + }, |
| 199 | + "execution_count": 8, |
| 200 | + "metadata": {}, |
| 201 | + "output_type": "execute_result" |
| 202 | + } |
| 203 | + ], |
| 204 | + "source": [ |
| 205 | + "x, y, z = mtf.to_transformed(b=0.5,c=10.)\n", |
| 206 | + "print(x, y, z)\n", |
| 207 | + "mtf.to_native(x=x, y=y, z=z)" |
| 208 | + ] |
| 209 | + }, |
| 210 | + { |
| 211 | + "cell_type": "markdown", |
| 212 | + "id": "07be7296-4be3-4c62-9a3e-95941b1b73ef", |
| 213 | + "metadata": {}, |
| 214 | + "source": [ |
| 215 | + "Additionally, as long as your custom transformer transforms to and from 3D cartesian coordinates and if the \"native\" coordinates match an xarray dataset field's dimensions, **you can hand off your custom transformer to `build_interpolated_cartesian_ds`** and build a yt cartesian dataset that reads and interpolates from an arbitrary coordinate system! " |
| 216 | + ] |
| 217 | + }, |
| 218 | + { |
| 219 | + "cell_type": "markdown", |
| 220 | + "id": "fb1249fa-fcca-4fff-b0e5-5757cd6a3c81", |
| 221 | + "metadata": {}, |
| 222 | + "source": [ |
| 223 | + "### Custom interpolations\n", |
| 224 | + "\n" |
| 225 | + ] |
| 226 | + }, |
| 227 | + { |
| 228 | + "cell_type": "code", |
| 229 | + "execution_count": null, |
| 230 | + "id": "45203947-4152-4e68-a12f-274f8ee1a978", |
| 231 | + "metadata": {}, |
| 232 | + "outputs": [], |
| 233 | + "source": [] |
| 234 | + } |
| 235 | + ], |
| 236 | + "metadata": { |
| 237 | + "kernelspec": { |
| 238 | + "display_name": "Python 3 (ipykernel)", |
| 239 | + "language": "python", |
| 240 | + "name": "python3" |
| 241 | + }, |
| 242 | + "language_info": { |
| 243 | + "codemirror_mode": { |
| 244 | + "name": "ipython", |
| 245 | + "version": 3 |
| 246 | + }, |
| 247 | + "file_extension": ".py", |
| 248 | + "mimetype": "text/x-python", |
| 249 | + "name": "python", |
| 250 | + "nbconvert_exporter": "python", |
| 251 | + "pygments_lexer": "ipython3", |
| 252 | + "version": "3.10.11" |
| 253 | + } |
| 254 | + }, |
| 255 | + "nbformat": 4, |
| 256 | + "nbformat_minor": 5 |
| 257 | +} |
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