tmp

example/CMakeLists.txt

@@ -25,5 +25,6 @@ add_example(mobser_tetra_ex2 OFF)
 add_example(mobser_tetra_sph_ex OFF)
 add_example(mobser_tesseroid_ex OFF)
 add_example(read_IGRF_ex OFF)
-add_example(read_Swarm_ex ON)
-add_example(power_spectrum_ex OFF)
+add_example(read_Swarm_ex OFF)
+add_example(power_spectrum_ex OFF)
+add_example(forward_mag_shc ON)

example/forward_mag_shc.cpp

@@ -0,0 +1,99 @@
+/********************************************************
+ *  ██████╗  ██████╗████████╗██╗
+ * ██╔════╝ ██╔════╝╚══██╔══╝██║
+ * ██║  ███╗██║        ██║   ██║
+ * ██║   ██║██║        ██║   ██║
+ * ╚██████╔╝╚██████╗   ██║   ███████╗
+ *  ╚═════╝  ╚═════╝   ╚═╝   ╚══════╝
+ * Geophysical Computational Tools & Library (GCTL)
+ *
+ * Copyright (c) 2022  Yi Zhang (yizhang-geo@zju.edu.cn)
+ *
+ * GCTL is distributed under a dual licensing scheme. You can redistribute 
+ * it and/or modify it under the terms of the GNU Lesser General Public 
+ * License as published by the Free Software Foundation, either version 2 
+ * of the License, or (at your option) any later version. You should have 
+ * received a copy of the GNU Lesser General Public License along with this 
+ * program. If not, see <http://www.gnu.org/licenses/>.
+ * 
+ * If the terms and conditions of the LGPL v.2. would prevent you from using 
+ * the GCTL, please consider the option to obtain a commercial license for a 
+ * fee. These licenses are offered by the GCTL's original author. As a rule, 
+ * licenses are provided "as-is", unlimited in time for a one time fee. Please 
+ * send corresponding requests to: yizhang-geo@zju.edu.cn. Please do not forget 
+ * to include some description of your company and the realm of its activities. 
+ * Also add information on how to contact you by electronic and paper mail.
+ ******************************************************/
+
+#include "gctl/core.h"
+#include "gctl/io.h"
+#include "gctl/potential.h"
+
+using namespace gctl;
+
+int main(int argc, char *argv[]) try
+{
+    // Read SHC coefficients
+    dsv_io shc_in;
+    shc_in.head_number(9);
+    shc_in.load_text("data/Ravaetal2020/LP1999_L1_d450", ".cof");
+    shc_in.info(HeadInfo|ColInfo);
+
+    _1d_array gnm, hnm;
+    shc_in.get_column(gnm, 3);
+    shc_in.get_column(hnm, 4);
+
+    // Prepare SHC data
+    //shc_data sd;
+    //sd.init(gnm, hnm, 1, 0, 450, 450);
+
+    // Prepare observation sites
+    array<point3ds> obsp;
+    grid_points_2d(obsp, -179.5, 179.5, -89.5, 89.5, 1.0, 1.0, 1737.4 + 30.0, TopLeft);
+
+    // Calculate over all observation sites
+    int id;
+    double rad, fx, fy, fz;
+    _1d_array P, dP;
+    _1d_array Br(obsp.size(), 0.0), Bt(obsp.size(), 0.0), Bp(obsp.size(), 0.0);
+
+    progress_bar bar(obsp.size(), "Progress");
+    for (int p = 0; p < obsp.size(); p++)
+    {
+        bar.progressed(p);
+
+        rad = obsp[p].rad;
+        schmidt_legendre(90.0 - obsp[p].lat, 450, P, dP);
+
+        // 注意跳过第0阶0次项
+        for (size_t i = 1; i <= 450; i++)
+        {
+            id = i*(i + 1)/2;
+            fx = pow(1737.4/rad, i+2);
+            fz = -1.0*(i+1)*pow(1737.4/rad, i+2);
+
+            for (size_t j = 0; j < i+1; j++)
+            {
+                fy = j/sind(90.0 - obsp[p].lat)*pow(1737.4/rad, i+2);
+
+                Bt[p] += -1.0*fx*(cosd(j*obsp[p].lon)*dP[id + j]*gnm[id + j] + sind(j*obsp[p].lon)*dP[id + j]*hnm[id + j]);
+                Bp[p] += fy*(sind(j*obsp[p].lon)*P[id + j]*gnm[id + j] - cosd(j*obsp[p].lon)*P[id + j]*hnm[id + j]);
+                Br[p] += fz*(cosd(j*obsp[p].lon)*P[id + j]*gnm[id + j] + sind(j*obsp[p].lon)*P[id + j]*hnm[id + j]);
+            }
+        }
+    }
+
+    geodsv_io magout;
+    magout.init_table(obsp.size(), 6);
+    magout.column_names({"lon", "lat", "rad", "Br", "Bt", "Bp"});
+    magout.fill_column_point3ds(obsp, "rad", "lon", "lat");
+    magout.fill_column(Br, "Br");
+    magout.fill_column(Bt, "Bt");
+    magout.fill_column(Bp, "Bp");
+    magout.save_csv("data/Ravaetal2020/LP1999_L1_d450_30km_grid");
+    return 0;
+}
+catch (std::exception &e)
+{
+    GCTL_ShowWhatError(e.what(), GCTL_ERROR_ERROR, 0, 0, 0);
+}

lib/potential/gm_data.cpp

@@ -27,6 +27,29 @@
 
 #include "gm_data.h"
 
+void gctl::shc_data::init(const _1d_array& s, const _1d_array& c, int n, int m, int N, int M, double t)
+{
+    ns = n;
+    ms = m;
+    ne = N;
+    me = M;
+    time = t;
+    Snm.resize((ne + 1)*(ne + 2)/2, 0.0);
+    Cnm.resize((ne + 1)*(ne + 2)/2, 0.0);
+
+    int i = 0;
+    for (int n = ns; n <= ne; n++)
+    {
+        for (int m = ms; m <= me; m++)
+        {
+            Snm[n*(n + 1)/2 + m] = s[i];
+            Cnm[n*(n + 1)/2 + m] = c[i];
+            i++;
+        }
+    }
+    return;
+}
+
 gctl::tensor gctl::transform_matrix(const point3ds &op)
 {
     tensor R;

lib/potential/gm_data.h

@@ -110,6 +110,7 @@ namespace gctl
         double time; // snapshot
         array<double> Snm, Cnm; // Snm or gnm, Cnm or hnm
 
+        void init(const _1d_array& s, const _1d_array& c, int n, int m, int N, int M, double t = 0.0);
         double coeff_s(int n, int m){return Snm[n*(n + 1)/2 + m];}
         double coeff_c(int n, int m){return Cnm[n*(n + 1)/2 + m];}
     };