mirror of https://github.com/ecmwf/eccodes.git
Merge pull request #200 from ecmwf/feature/healpix-orderingConvention-nested
ECC-1784 GRIB: HealPix Geoiterator: Support nested ordering
This commit is contained in:
shahramn
GitHub
commit
6dfd9bee75
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@ -9,9 +9,13 @@
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*/
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#include "grib_api_internal.h"
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#include <cmath>
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#include <vector>
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#include <algorithm>
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#include <bitset>
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#include <cmath>
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#include <cstdint>
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#include <tuple>
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#include <vector>
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/*
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This is used by make_class.pl
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@ -24,6 +28,7 @@
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MEMBERS = double *lats
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MEMBERS = double *lons
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MEMBERS = long Nsides
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MEMBERS = bool nested
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END_CLASS_DEF
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*/
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@ -54,6 +59,7 @@ typedef struct grib_iterator_healpix{
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double *lats;
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double *lons;
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long Nsides;
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bool nested;
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} grib_iterator_healpix;
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extern grib_iterator_class* grib_iterator_class_gen;
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@ -84,7 +90,77 @@ static void init_class(grib_iterator_class* c)
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/* END_CLASS_IMP */
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#define ITER "HEALPix Geoiterator"
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#define RAD2DEG 57.29577951308232087684 // 180 over pi
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constexpr double RAD2DEG = 57.29577951308232087684; // 180 over pi
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namespace
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{
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struct CodecFijNest
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{
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static constexpr uint64_t __masks[] = { 0x00000000ffffffff, 0x0000ffff0000ffff, 0x00ff00ff00ff00ff,
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0x0f0f0f0f0f0f0f0f, 0x3333333333333333, 0x5555555555555555 };
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inline static int nest_encode_bits(int n)
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{
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auto b = static_cast<uint64_t>(n) & __masks[0];
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b = (b ^ (b << 16)) & __masks[1];
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b = (b ^ (b << 8)) & __masks[2];
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b = (b ^ (b << 4)) & __masks[3];
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b = (b ^ (b << 2)) & __masks[4];
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b = (b ^ (b << 1)) & __masks[5];
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return static_cast<int>(b);
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}
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// inline static int nest_decode_bits(int n)
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// {
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// auto b = static_cast<uint64_t>(n) & __masks[5];
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// b = (b ^ (b >> 1)) & __masks[4];
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// b = (b ^ (b >> 2)) & __masks[3];
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// b = (b ^ (b >> 4)) & __masks[2];
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// b = (b ^ (b >> 8)) & __masks[1];
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// b = (b ^ (b >> 16)) & __masks[0];
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// return static_cast<int>(b);
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// }
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// static std::tuple<int, int, int> nest_to_fij(int n, int k)
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// {
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// Assert(0 <= n);
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// auto f = n >> (2 * k); // f = n / (Nside * Nside)
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// n &= (1 << (2 * k)) - 1; // n = n % (Nside * Nside)
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// auto i = nest_decode_bits(n);
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// auto j = nest_decode_bits(n >> 1);
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// return { f, i, j };
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// }
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static int fij_to_nest(int f, int i, int j, int k)
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{
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return (f << (2 * k)) + nest_encode_bits(i) + (nest_encode_bits(j) << 1);
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}
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};
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inline int int_sqrt(int n)
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{
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return static_cast<int>(std::sqrt(static_cast<double>(n) + 0.5));
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}
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// for division result within [0; 3]
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inline int div_03(int a, int b)
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{
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int t = (a >= (b << 1)) ? 1 : 0;
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a -= t * (b << 1);
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return (t << 1) + (a >= b ? 1 : 0);
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}
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inline bool is_power_of_2(int n)
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{
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return std::bitset<sizeof(int) * 8>(n).count() == 1;
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}
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inline int pll(int f)
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{
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constexpr int __pll[] = { 1, 3, 5, 7, 0, 2, 4, 6, 1, 3, 5, 7 };
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return __pll[f];
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}
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size_t HEALPix_nj(size_t N, size_t i)
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{
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@ -137,42 +213,127 @@ static std::vector<double> HEALPix_longitudes(size_t N, size_t i)
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static int iterate_healpix(grib_iterator_healpix* self, long N)
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{
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size_t ny, nx;
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ny = nx = 4*N - 1;
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std::vector<double> latitudes(ny);
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size_t Ny = 4 * static_cast<size_t>(N) - 1;
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auto Nd = static_cast<double>(N);
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std::vector<double> latitudes(Ny);
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for (long r = 1; r < N; r++) {
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latitudes[r - 1] = 90.0 - RAD2DEG * std::acos(1.0 - r * r / (3.0 * N * N));
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auto rd = static_cast<double>(r);
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latitudes[r - 1] = 90.0 - RAD2DEG * std::acos(1.0 - rd * rd / (3.0 * Nd * Nd));
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latitudes[4 * N - 1 - r] = -latitudes[r - 1];
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}
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// Polar caps
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for (long r = 1; r < N; r++) {
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latitudes[r - 1] = 90.0 - RAD2DEG * std::acos(1.0 - r * r / (3.0 * N * N));
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auto rd = static_cast<double>(r);
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latitudes[r - 1] = 90.0 - RAD2DEG * std::acos(1.0 - rd * rd / (3.0 * Nd * Nd));
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latitudes[4 * N - 1 - r] = -latitudes[r - 1];
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}
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// Equatorial belt
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for (long r = N; r < 2 * N; r++) {
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latitudes[r - 1] = 90.0 - RAD2DEG * std::acos((4.0 * N - 2.0 * r) / (3.0 * N));
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auto rd = static_cast<double>(r);
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latitudes[r - 1] = 90.0 - RAD2DEG * std::acos((4.0 * Nd - 2.0 * rd) / (3.0 * Nd));
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latitudes[4 * N - 1 - r] = -latitudes[r - 1];
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}
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// Equator
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latitudes[2 * N - 1] = 0.0;
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size_t k = 0;
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for (size_t i = 0; i < ny; i++) {
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if (self->nested) {
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if (!is_power_of_2(N)) {
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grib_context* c = grib_context_get_default();
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grib_context_log(c, GRIB_LOG_ERROR, "%s: For nested ordering, Nside must be a power of 2", ITER);
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return GRIB_WRONG_GRID;
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}
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const auto Nside = static_cast<int>(N);
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const auto k = static_cast<int>(std::log2(Nside));
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const int Npix = 12 * Nside * Nside;
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const int Ncap = (Nside * (Nside - 1)) << 1;
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auto to_nest = [&](int f, //!< base pixel index
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int ring, //!< 1-based ring number
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int Nring, //!< number of pixels in ring
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int phi, //!< index in longitude
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int shift //!< if ring's first pixel is not at phi=0
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) -> int {
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int r = ((2 + (f >> 2)) << k) - ring - 1;
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int p = 2 * phi - pll(f) * Nring - shift - 1;
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if (p >= 2 * Nside) {
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p -= 8 * Nside;
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}
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int i = (r + p) >> 1;
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int j = (r - p) >> 1;
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Assert(f < 12 && i < Nside && j < Nside);
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return CodecFijNest::fij_to_nest(f, i, j, k);
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};
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std::vector<size_t> ring_to_nest(Npix);
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for (int r = 0; r < Npix; ++r) {
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if (r < Ncap) {
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// North polar cap
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int Nring = (1 + int_sqrt(2 * r + 1)) >> 1;
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int phi = 1 + r - 2 * Nring * (Nring - 1);
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int f = div_03(phi - 1, Nring);
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ring_to_nest[r] = to_nest(f, Nring, Nring, phi, 0);
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continue;
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}
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if (Npix - Ncap <= r) {
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// South polar cap
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int Nring = (1 + int_sqrt(2 * Npix - 2 * r - 1)) >> 1;
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int phi = 1 + r + 2 * Nring * (Nring - 1) + 4 * Nring - Npix;
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int ring = 4 * Nside - Nring; // (from South pole)
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int f = div_03(phi - 1, Nring) + 8;
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ring_to_nest[r] = to_nest(f, ring, Nring, phi, 0);
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continue;
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}
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// Equatorial belt
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int ip = r - Ncap;
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int tmp = ip >> (k + 2);
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int phi = ip - tmp * 4 * Nside + 1;
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int ring = tmp + Nside;
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int ifm = 1 + ((phi - 1 - ((1 + tmp) >> 1)) >> k);
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int ifp = 1 + ((phi - 1 - ((1 - tmp + 2 * Nside) >> 1)) >> k);
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int f = (ifp == ifm) ? (ifp | 4) : ((ifp < ifm) ? ifp : (ifm + 8));
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ring_to_nest[r] = to_nest(f, ring, Nside, phi, ring & 1);
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}
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for (size_t i = 0, j=0; i < Ny; i++) {
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// Compute the longitudes at a given latitude
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std::vector<double> longitudes = HEALPix_longitudes(N, i);
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for (size_t j = 0; j < longitudes.size(); j++) {
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self->lons[k] = longitudes[j];
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self->lats[k] = latitudes[i];
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++k;
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for (double longitude : HEALPix_longitudes(N, i)) {
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Assert( ring_to_nest.at(j) < Npix );
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self->lons[ring_to_nest.at(j)] = longitude;
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self->lats[ring_to_nest.at(j)] = latitudes[i];
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++j;
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}
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}
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} else {
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for (size_t i = 0, j = 0; i < Ny; i++) {
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// Compute the longitudes at a given latitude
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for (double longitude : HEALPix_longitudes(N, i)) {
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self->lons[j] = longitude;
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self->lats[j] = latitudes[i];
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++j;
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}
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}
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}
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return GRIB_SUCCESS;
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}
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} // anonymous namespace
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static int init(grib_iterator* iter, grib_handle* h, grib_arguments* args)
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{
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int err = 0;
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@ -182,7 +343,9 @@ static int init(grib_iterator* iter, grib_handle* h, grib_arguments* args)
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const char* sorder = grib_arguments_get_name(h, args, self->carg++);
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long N = 0;
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if ((err = grib_get_long_internal(h, snside, &N)) != GRIB_SUCCESS) return err;
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if ((err = grib_get_long_internal(h, snside, &N)) != GRIB_SUCCESS) {
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return err;
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}
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if (N <= 0) {
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grib_context_log(h->context, GRIB_LOG_ERROR, "%s: Key %s must be greater than zero", ITER, snside);
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return GRIB_WRONG_GRID;
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@ -190,11 +353,17 @@ static int init(grib_iterator* iter, grib_handle* h, grib_arguments* args)
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char ordering[32] = {0,};
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size_t slen = sizeof(ordering);
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if ((err = grib_get_string_internal(h, sorder, ordering, &slen)) != GRIB_SUCCESS)
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if ((err = grib_get_string_internal(h, sorder, ordering, &slen)) != GRIB_SUCCESS) {
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return err;
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}
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if (!STR_EQUAL(ordering, "ring")) {
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grib_context_log(h->context, GRIB_LOG_ERROR, "%s: Only ring ordering is supported", ITER);
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self->nested = STR_EQUAL(ordering, "nested");
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if (!STR_EQUAL(ordering, "ring") && !self->nested) {
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grib_context_log(h->context, GRIB_LOG_ERROR, "%s: Only orderingConvention=(ring|nested) are supported", ITER);
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return GRIB_GEOCALCULUS_PROBLEM;
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}
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if (self->nested && N == 1) {
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grib_context_log(h->context, GRIB_LOG_ERROR, "%s: For orderingConvention=nested, N must be greater than 1", ITER);
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return GRIB_GEOCALCULUS_PROBLEM;
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}
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@ -210,9 +379,14 @@ static int init(grib_iterator* iter, grib_handle* h, grib_arguments* args)
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}
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self->lats = (double*)grib_context_malloc(h->context, iter->nv * sizeof(double));
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if (self->lats == NULL) return GRIB_OUT_OF_MEMORY;
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if (self->lats == nullptr) {
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return GRIB_OUT_OF_MEMORY;
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}
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self->lons = (double*)grib_context_malloc(h->context, iter->nv * sizeof(double));
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if (self->lons == NULL) return GRIB_OUT_OF_MEMORY;
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if (self->lons == nullptr) {
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return GRIB_OUT_OF_MEMORY;
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}
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try {
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err = iterate_healpix(self, N);
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@ -228,24 +402,26 @@ static int init(grib_iterator* iter, grib_handle* h, grib_arguments* args)
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static int next(grib_iterator* iter, double* lat, double* lon, double* val)
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{
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grib_iterator_healpix* self = (grib_iterator_healpix*)iter;
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auto* self = (grib_iterator_healpix*)iter;
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if ((long)iter->e >= (long)(iter->nv - 1))
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if (iter->e >= static_cast<long>(iter->nv - 1)) {
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return 0;
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}
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iter->e++;
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*lat = self->lats[iter->e];
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*lon = self->lons[iter->e];
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if (val && iter->data) {
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if (val != nullptr && iter->data != nullptr) {
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*val = iter->data[iter->e];
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}
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return 1;
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}
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static int destroy(grib_iterator* i)
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static int destroy(grib_iterator* iter)
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{
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grib_iterator_healpix* self = (grib_iterator_healpix*)i;
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const grib_context* c = i->h->context;
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auto* self = (grib_iterator_healpix*)iter;
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const auto* c = iter->h->context;
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grib_context_free(c, self->lats);
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grib_context_free(c, self->lons);
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@ -72,8 +72,59 @@ EOF
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${tools_dir}/grib_filter $tempFilt $tempGrib
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# Invalid cases
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# --------------
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# Nested ordering
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# ---------------
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rm -f $tempGrib
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cat > $tempFilt <<EOF
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set tablesVersion = $latest;
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set gridType = "healpix";
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set longitudeOfFirstGridPointInDegrees = 45;
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set numberOfPointsAlongASide = 2;
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set orderingConvention = "nested";
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set values = { 0,1,2,3,4,5,6,7,
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8,9,10,11,12,13,14,15,
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16,17,18,19,20,21,22,23,
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24,25,26,27,28,29,30,31,
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32,33,34,35,36,37,38,39,
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40,41,42,43,44,45,46,47};
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# count of values = 48 = 12 * N * N
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write;
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EOF
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${tools_dir}/grib_filter -o $tempGrib $tempFilt $input
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${tools_dir}/grib_get_data $tempGrib > $tempLog
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# Nested: N must be a power of 2
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input=$ECCODES_SAMPLES_PATH/GRIB2.tmpl
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${tools_dir}/grib_set -s gridType=healpix,Nside=3,orderingConvention=nested,numberOfDataPoints=108,numberOfValues=108 $input $tempGrib
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set +e
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${tools_dir}/grib_get_data $tempGrib > $tempLog 2>&1
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status=$?
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set -e
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[ $status -ne 0 ]
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grep -q "Nside must be a power of 2" $tempLog
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# Nested. Bad N
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${tools_dir}/grib_set -s gridType=healpix,Nside=1,orderingConvention=nested $input $tempGrib
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set +e
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${tools_dir}/grib_get_data $tempGrib > $tempLog 2>&1
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status=$?
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set -e
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[ $status -ne 0 ]
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cat $tempLog
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grep -q "N must be greater than 1" $tempLog
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# Bad ordering
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${tools_dir}/grib_set -s gridType=healpix,Nside=1,ordering=6 $input $tempGrib
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set +e
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${tools_dir}/grib_get_data $tempGrib > $tempLog 2>&1
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status=$?
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set -e
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[ $status -ne 0 ]
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grep -q "Only orderingConvention.*are supported" $tempLog
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# N = 0
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set +e
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${tools_dir}/grib_get_data -sN=0 $tempGrib > $tempLog 2>&1
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status=$?
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@ -81,13 +132,6 @@ set -e
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[ $status -ne 0 ]
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grep -q "Nside must be greater than zero" $tempLog
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set +e
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${tools_dir}/grib_get_data -s orderingConvention=nested $tempGrib > $tempLog 2>&1
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status=$?
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set -e
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[ $status -ne 0 ]
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grep -q "Only ring ordering is supported" $tempLog
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# Clean up
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rm -f $tempFilt $tempGrib $tempLog
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@ -227,7 +227,8 @@ static int process_file(const char* filename)
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}
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if (fabs(lon2 - expected_lon2) > angular_tolerance) {
|
||||
error(filename, msg_num, "longitudeOfLastGridPointInDegrees=%f but should be %f\n", lon2, expected_lon2);
|
||||
error(filename, msg_num, "longitudeOfLastGridPointInDegrees=%f but should be %f (= 360 - 360/max(pl) )\n",
|
||||
lon2, expected_lon2);
|
||||
}
|
||||
|
||||
GRIB_CHECK(grib_get_size(h, "values", &sizeOfValuesArray), 0);
|
||||
|
|
|
|||
Loading…
Reference in New Issue