|
| 1 | +import numpy as np |
| 2 | +from numba import njit |
| 3 | + |
| 4 | + |
| 5 | +@njit(cache=True) |
| 6 | +def states(a, qx, qy, ng, idir): |
| 7 | + r""" |
| 8 | + Predict the cell-centered state to the edges in one-dimension using the |
| 9 | + reconstructed, limited slopes. We use a fourth-order Godunov method. |
| 10 | +
|
| 11 | + Our convention here is that: |
| 12 | +
|
| 13 | + ``al[i,j]`` will be :math:`al_{i-1/2,j}`, |
| 14 | +
|
| 15 | + ``al[i+1,j]`` will be :math:`al_{i+1/2,j}`. |
| 16 | +
|
| 17 | + Parameters |
| 18 | + ---------- |
| 19 | + a : ndarray |
| 20 | + The cell-centered state. |
| 21 | + qx, qy : int |
| 22 | + The dimensions of `a`. |
| 23 | + ng : int |
| 24 | + The number of ghost cells |
| 25 | + idir : int |
| 26 | + Are we predicting to the edges in the x-direction (1) or y-direction (2)? |
| 27 | +
|
| 28 | + Returns |
| 29 | + ------- |
| 30 | + out : ndarray, ndarray |
| 31 | + The state predicted to the left and right edges. |
| 32 | + """ |
| 33 | + |
| 34 | + al = np.zeros((qx, qy)) |
| 35 | + ar = np.zeros((qx, qy)) |
| 36 | + |
| 37 | + a_int = np.zeros((qx, qy)) |
| 38 | + dafm = np.zeros((qx, qy)) |
| 39 | + dafp = np.zeros((qx, qy)) |
| 40 | + d2af = np.zeros((qx, qy)) |
| 41 | + d2ac = np.zeros((qx, qy)) |
| 42 | + d3a = np.zeros((qx, qy)) |
| 43 | + |
| 44 | + C2 = 1.25 |
| 45 | + C3 = 0.1 |
| 46 | + |
| 47 | + nx = qx - 2 * ng |
| 48 | + ny = qy - 2 * ng |
| 49 | + ilo = ng |
| 50 | + ihi = ng + nx |
| 51 | + jlo = ng |
| 52 | + jhi = ng + ny |
| 53 | + |
| 54 | + # we need interface values on all faces of the domain |
| 55 | + if (idir == 1): |
| 56 | + |
| 57 | + for i in range(ilo - 2, ihi + 3): |
| 58 | + for j in range(jlo - 1, jhi + 1): |
| 59 | + |
| 60 | + # interpolate to the edges |
| 61 | + a_int[i, j] = (7.0 / 12.0) * (a[i - 1, j] + a[i, j]) - \ |
| 62 | + (1.0 / 12.0) * (a[i - 2, j] + a[i + 1, j]) |
| 63 | + |
| 64 | + al[i, j] = a_int[i, j] |
| 65 | + ar[i, j] = a_int[i, j] |
| 66 | + |
| 67 | + for i in range(ilo - 2, ihi + 3): |
| 68 | + for j in range(jlo - 1, jhi + 1): |
| 69 | + # these live on cell-centers |
| 70 | + dafm[i, j] = a[i, j] - a_int[i, j] |
| 71 | + dafp[i, j] = a_int[i + 1, j] - a[i, j] |
| 72 | + |
| 73 | + # these live on cell-centers |
| 74 | + d2af[i, j] = 6.0 * (a_int[i, j] - 2.0 * |
| 75 | + a[i, j] + a_int[i + 1, j]) |
| 76 | + |
| 77 | + for i in range(ilo - 3, ihi + 3): |
| 78 | + for j in range(jlo - 1, jhi + 1): |
| 79 | + d2ac[i, j] = a[i - 1, j] - 2.0 * a[i, j] + a[i + 1, j] |
| 80 | + |
| 81 | + for i in range(ilo - 2, ihi + 3): |
| 82 | + for j in range(jlo - 1, jhi + 1): |
| 83 | + # this lives on the interface |
| 84 | + d3a[i, j] = d2ac[i, j] - d2ac[i - 1, j] |
| 85 | + |
| 86 | + # this is a look over cell centers, affecting |
| 87 | + # i-1/2,R and i+1/2,L |
| 88 | + for i in range(ilo - 1, ihi + 1): |
| 89 | + for j in range(jlo - 1, jhi + 1): |
| 90 | + |
| 91 | + # limit? MC Eq. 24 and 25 |
| 92 | + if (dafm[i, j] * dafp[i, j] <= 0.0 or |
| 93 | + (a[i, j] - a[i - 2, j]) * (a[i + 2, j] - a[i, j]) <= 0.0): |
| 94 | + |
| 95 | + # we are at an extrema |
| 96 | + |
| 97 | + s = np.copysign(1.0, d2ac[i, j]) |
| 98 | + if (s == np.copysign(1.0, d2ac[i - 1, j]) and s == np.copysign(1.0, d2ac[i + 1, j]) and |
| 99 | + s == np.copysign(1.0, d2af[i, j])): |
| 100 | + # MC Eq. 26 |
| 101 | + d2a_lim = s * min(abs(d2af[i, j]), C2 * abs(d2ac[i - 1, j]), |
| 102 | + C2 * abs(d2ac[i, j]), C2 * abs(d2ac[i + 1, j])) |
| 103 | + else: |
| 104 | + d2a_lim = 0.0 |
| 105 | + |
| 106 | + if (abs(d2af[i, j]) <= 1.e-12 * max(abs(a[i - 2, j]), abs(a[i - 1, j]), |
| 107 | + abs(a[i, j]), abs(a[i + 1, j]), abs(a[i + 2, j]))): |
| 108 | + rho = 0.0 |
| 109 | + else: |
| 110 | + # MC Eq. 27 |
| 111 | + rho = d2a_lim / d2af[i, j] |
| 112 | + |
| 113 | + if (rho < 1.0 - 1.e-12): |
| 114 | + # we may need to limit -- these quantities are at cell-centers |
| 115 | + d3a_min = min(d3a[i - 1, j], d3a[i, j], |
| 116 | + d3a[i + 1, j], d3a[i + 2, j]) |
| 117 | + d3a_max = max(d3a[i - 1, j], d3a[i, j], |
| 118 | + d3a[i + 1, j], d3a[i + 2, j]) |
| 119 | + |
| 120 | + if (C3 * max(abs(d3a_min), abs(d3a_max)) <= (d3a_max - d3a_min)): |
| 121 | + # limit |
| 122 | + if (dafm[i, j] * dafp[i, j] < 0.0): |
| 123 | + # Eqs. 29, 30 |
| 124 | + ar[i, j] = a[i, j] - rho * \ |
| 125 | + dafm[i, j] # note: typo in Eq 29 |
| 126 | + al[i + 1, j] = a[i, j] + rho * dafp[i, j] |
| 127 | + elif (abs(dafm[i, j]) >= 2.0 * abs(dafp[i, j])): |
| 128 | + # Eq. 31 |
| 129 | + ar[i, j] = a[i, j] - 2.0 * \ |
| 130 | + (1.0 - rho) * dafp[i, j] - rho * dafm[i, j] |
| 131 | + elif (abs(dafp[i, j]) >= 2.0 * abs(dafm[i, j])): |
| 132 | + # Eq. 32 |
| 133 | + al[i + 1, j] = a[i, j] + 2.0 * \ |
| 134 | + (1.0 - rho) * dafm[i, j] + rho * dafp[i, j] |
| 135 | + |
| 136 | + else: |
| 137 | + # if Eqs. 24 or 25 didn't hold we still may need to limit |
| 138 | + if (abs(dafm[i, j]) >= 2.0 * abs(dafp[i, j])): |
| 139 | + ar[i, j] = a[i, j] - 2.0 * dafp[i, j] |
| 140 | + |
| 141 | + if (abs(dafp[i, j]) >= 2.0 * abs(dafm[i, j])): |
| 142 | + al[i + 1, j] = a[i, j] + 2.0 * dafm[i, j] |
| 143 | + |
| 144 | + elif (idir == 2): |
| 145 | + |
| 146 | + for i in range(ilo - 1, ihi + 1): |
| 147 | + for j in range(jlo - 2, jhi + 3): |
| 148 | + |
| 149 | + # interpolate to the edges |
| 150 | + a_int[i, j] = (7.0 / 12.0) * (a[i, j - 1] + a[i, j]) - \ |
| 151 | + (1.0 / 12.0) * (a[i, j - 2] + a[i, j + 1]) |
| 152 | + |
| 153 | + al[i, j] = a_int[i, j] |
| 154 | + ar[i, j] = a_int[i, j] |
| 155 | + |
| 156 | + for i in range(ilo - 1, ihi + 1): |
| 157 | + for j in range(jlo - 2, jhi + 3): |
| 158 | + # these live on cell-centers |
| 159 | + dafm[i, j] = a[i, j] - a_int[i, j] |
| 160 | + dafp[i, j] = a_int[i, j + 1] - a[i, j] |
| 161 | + |
| 162 | + # these live on cell-centers |
| 163 | + d2af[i, j] = 6.0 * (a_int[i, j] - 2.0 * |
| 164 | + a[i, j] + a_int[i, j + 1]) |
| 165 | + |
| 166 | + for i in range(ilo - 1, ihi + 1): |
| 167 | + for j in range(jlo - 3, jhi + 3): |
| 168 | + d2ac[i, j] = a[i, j - 1] - 2.0 * a[i, j] + a[i, j + 1] |
| 169 | + |
| 170 | + for i in range(ilo - 1, ihi + 1): |
| 171 | + for j in range(jlo - 2, jhi + 2): |
| 172 | + # this lives on the interface |
| 173 | + d3a[i, j] = d2ac[i, j] - d2ac[i, j - 1] |
| 174 | + |
| 175 | + # this is a look over cell centers, affecting |
| 176 | + # j-1/2,R and j+1/2,L |
| 177 | + for i in range(ilo - 1, ihi + 1): |
| 178 | + for j in range(jlo - 1, jhi + 1): |
| 179 | + |
| 180 | + # limit? MC Eq. 24 and 25 |
| 181 | + if (dafm[i, j] * dafp[i, j] <= 0.0 or |
| 182 | + (a[i, j] - a[i, j - 2]) * (a[i, j + 2] - a[i, j]) <= 0.0): |
| 183 | + |
| 184 | + # we are at an extrema |
| 185 | + |
| 186 | + s = np.copysign(1.0, d2ac[i, j]) |
| 187 | + if (s == np.copysign(1.0, d2ac[i, j - 1]) and s == np.copysign(1.0, d2ac[i, j + 1]) and |
| 188 | + s == np.copysign(1.0, d2af[i, j])): |
| 189 | + # MC Eq. 26 |
| 190 | + d2a_lim = s * min(abs(d2af[i, j]), C2 * abs(d2ac[i, j - 1]), |
| 191 | + C2 * abs(d2ac[i, j]), C2 * abs(d2ac[i, j + 1])) |
| 192 | + else: |
| 193 | + d2a_lim = 0.0 |
| 194 | + |
| 195 | + if (abs(d2af[i, j]) <= 1.e-12 * max(abs(a[i, j - 2]), abs(a[i, j - 1]), |
| 196 | + abs(a[i, j]), abs(a[i, j + 1]), abs(a[i, j + 2]))): |
| 197 | + rho = 0.0 |
| 198 | + else: |
| 199 | + # MC Eq. 27 |
| 200 | + rho = d2a_lim / d2af[i, j] |
| 201 | + |
| 202 | + if (rho < 1.0 - 1.e-12): |
| 203 | + # we may need to limit -- these quantities are at cell-centers |
| 204 | + d3a_min = min(d3a[i, j - 1], d3a[i, j], |
| 205 | + d3a[i, j + 1], d3a[i, j + 2]) |
| 206 | + d3a_max = max(d3a[i, j - 1], d3a[i, j], |
| 207 | + d3a[i, j + 1], d3a[i, j + 2]) |
| 208 | + |
| 209 | + if (C3 * max(abs(d3a_min), abs(d3a_max)) <= (d3a_max - d3a_min)): |
| 210 | + # limit |
| 211 | + if (dafm[i, j] * dafp[i, j] < 0.0): |
| 212 | + # Eqs. 29, 30 |
| 213 | + ar[i, j] = a[i, j] - rho * \ |
| 214 | + dafm[i, j] # note: typo in Eq 29 |
| 215 | + al[i, j + 1] = a[i, j] + rho * dafp[i, j] |
| 216 | + elif (abs(dafm[i, j]) >= 2.0 * abs(dafp[i, j])): |
| 217 | + # Eq. 31 |
| 218 | + ar[i, j] = a[i, j] - 2.0 * \ |
| 219 | + (1.0 - rho) * dafp[i, j] - rho * dafm[i, j] |
| 220 | + elif (abs(dafp[i, j]) >= 2.0 * abs(dafm[i, j])): |
| 221 | + # Eq. 32 |
| 222 | + al[i, j + 1] = a[i, j] + 2.0 * \ |
| 223 | + (1.0 - rho) * dafm[i, j] + rho * dafp[i, j] |
| 224 | + |
| 225 | + else: |
| 226 | + # if Eqs. 24 or 25 didn't hold we still may need to limit |
| 227 | + if (abs(dafm[i, j]) >= 2.0 * abs(dafp[i, j])): |
| 228 | + ar[i, j] = a[i, j] - 2.0 * dafp[i, j] |
| 229 | + |
| 230 | + if (abs(dafp[i, j]) >= 2.0 * abs(dafm[i, j])): |
| 231 | + al[i, j + 1] = a[i, j] + 2.0 * dafm[i, j] |
| 232 | + |
| 233 | + return al, ar |
| 234 | + |
| 235 | + |
| 236 | +@njit(cache=True) |
| 237 | +def states_nolimit(a, qx, qy, ng, idir): |
| 238 | + r""" |
| 239 | + Predict the cell-centered state to the edges in one-dimension using the |
| 240 | + reconstructed slopes (and without slope limiting). We use a fourth-order |
| 241 | + Godunov method. |
| 242 | +
|
| 243 | + Our convention here is that: |
| 244 | +
|
| 245 | + ``al[i,j]`` will be :math:`al_{i-1/2,j}`, |
| 246 | +
|
| 247 | + ``al[i+1,j]`` will be :math:`al_{i+1/2,j}`. |
| 248 | +
|
| 249 | + Parameters |
| 250 | + ---------- |
| 251 | + a : ndarray |
| 252 | + The cell-centered state. |
| 253 | + qx, qy : int |
| 254 | + The dimensions of `a`. |
| 255 | + ng : int |
| 256 | + The number of ghost cells |
| 257 | + idir : int |
| 258 | + Are we predicting to the edges in the x-direction (1) or y-direction (2)? |
| 259 | +
|
| 260 | + Returns |
| 261 | + ------- |
| 262 | + out : ndarray, ndarray |
| 263 | + The state predicted to the left and right edges. |
| 264 | + """ |
| 265 | + |
| 266 | + a_int = np.zeros((qx, qy)) |
| 267 | + al = np.zeros((qx, qy)) |
| 268 | + ar = np.zeros((qx, qy)) |
| 269 | + |
| 270 | + nx = qx - 2 * ng |
| 271 | + ny = qy - 2 * ng |
| 272 | + ilo = ng |
| 273 | + ihi = ng + nx |
| 274 | + jlo = ng |
| 275 | + jhi = ng + ny |
| 276 | + |
| 277 | + # we need interface values on all faces of the domain |
| 278 | + if (idir == 1): |
| 279 | + |
| 280 | + for i in range(ilo - 2, ihi + 3): |
| 281 | + for j in range(jlo - 1, jhi + 1): |
| 282 | + |
| 283 | + # interpolate to the edges |
| 284 | + a_int[i, j] = (7.0 / 12.0) * (a[i - 1, j] + a[i, j]) - \ |
| 285 | + (1.0 / 12.0) * (a[i - 2, j] + a[i + 1, j]) |
| 286 | + |
| 287 | + al[i, j] = a_int[i, j] |
| 288 | + ar[i, j] = a_int[i, j] |
| 289 | + |
| 290 | + elif (idir == 2): |
| 291 | + |
| 292 | + for i in range(ilo - 1, ihi + 1): |
| 293 | + for j in range(jlo - 2, jhi + 3): |
| 294 | + |
| 295 | + # interpolate to the edges |
| 296 | + a_int[i, j] = (7.0 / 12.0) * (a[i, j - 1] + a[i, j]) - \ |
| 297 | + (1.0 / 12.0) * (a[i, j - 2] + a[i, j + 1]) |
| 298 | + |
| 299 | + al[i, j] = a_int[i, j] |
| 300 | + ar[i, j] = a_int[i, j] |
| 301 | + |
| 302 | + return al, ar |
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