Add API wrapper for calculating FD coefficients.

src/common/fd_coeff2.cpp

@@ -0,0 +1,75 @@
+/*****************************************************************************
+
+YASK: Yet Another Stencil Kernel
+Copyright (c) 2014-2019, Intel Corporation
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+* The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+
+*****************************************************************************/
+
+///////// FD coefficients implementation.
+
+#include "yask_common_api.hpp"
+#include "fd_coeff.hpp"
+#include "common_utils.hpp"
+
+using namespace std;
+
+namespace yask {
+
+    // C++-style interface.
+    vector<double> get_arbitrary_fd_coefficients(int derivative_order, double eval_point, const vector<double> sample_points) {
+        if (derivative_order < 1)
+            THROW_YASK_EXCEPTION("Error: get_fd_coefficients() called with derivative-order less than 1");
+        int n = int(sample_points.size());
+        if (n < 2)
+            THROW_YASK_EXCEPTION("Error: get_fd_coefficients() called with fewer than 2 sample points");
+        vector<double> coeffs(n);
+        fd_coeff(&coeffs[0], double(eval_point), derivative_order, &sample_points[0], n);
+        return coeffs;
+    }
+
+    // Common FD forms for uniform grid spacing.
+    vector<double> get_center_fd_coefficients(int derivative_order, int radius) {
+        if (radius < 1)
+            THROW_YASK_EXCEPTION("get_center_fd_coefficients() called with less than radius 1");
+        vector<double> pts;
+        for (int i = -radius; i <= radius; i++)
+            pts.push_back(i);
+        assert(sizeof(pts) == size_t(radius * 2 + 1));
+        return get_arbitrary_fd_coefficients(derivative_order, 0, pts);
+    }
+    vector<double> get_forward_fd_coefficients(int derivative_order, int accuracy_order) {
+        if (accuracy_order < 1)
+            THROW_YASK_EXCEPTION("get_forward_fd_coefficients() called with less than order-of-accuracy 1");
+        vector<double> pts;
+        for (int i = 0; i <= accuracy_order; i++)
+            pts.push_back(i);
+        return get_arbitrary_fd_coefficients(derivative_order, 0, pts);
+    }
+    vector<double> get_backward_fd_coefficients(int derivative_order, int accuracy_order) {
+        if (accuracy_order < 1)
+            THROW_YASK_EXCEPTION("get_backward_fd_coefficients() called with less than order-of-accuracy 1");
+        vector<double> pts;
+        for (int i = -accuracy_order; i <= 0; i++)
+            pts.push_back(i);
+        return get_arbitrary_fd_coefficients(derivative_order, 0, pts);
+    }
+
+} // yask namespace.