From 737cc68780c231608f513122430af7c831692def Mon Sep 17 00:00:00 2001
From: Christoph Lehmann <christoph.lehmann@ufz.de>
Date: Tue, 1 Sep 2015 14:35:41 +0200
Subject: [PATCH] Added function for shape matrix interpolation.
---
NumLib/Function/Interpolation.h | 43 +++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
create mode 100644 NumLib/Function/Interpolation.h
diff --git a/NumLib/Function/Interpolation.h b/NumLib/Function/Interpolation.h
new file mode 100644
index 00000000000..975883436b0
--- /dev/null
+++ b/NumLib/Function/Interpolation.h
@@ -0,0 +1,43 @@
+#ifndef NUMLIB_INTERPOLATION_H
+#define NUMLIB_INTERPOLATION_H
+
+namespace NumLib
+{
+
+/**
+ * Interpolates variables given at element nodes according to the given shape matrix.
+ *
+ * This function simply does the usual finite-element interpolation, i.e. multiplication
+ * of nodal values with the shape function.
+ *
+ * @param nodal_values vector of nodal values
+ * @param shape_matrix_N shape matrix of the point to which will be interpolated
+ * @param num_nodal_dof number of nodal variables that will be interpolated
+ * @param interpolated_values array of addresses to which the interpolated values will be written
+ *
+ * The size of interpolated_values must be equal to num_nodal_dof.
+ */
+template<typename NodalValues, typename ShapeMatrix>
+void shapeFunctionInterpolate(
+ const NodalValues& nodal_values,
+ const ShapeMatrix& shape_matrix_N,
+ const unsigned num_nodal_dof,
+ double** interpolated_values
+ )
+{
+ auto const num_nodes = shape_matrix_N.size();
+
+ for (unsigned d=0; d<num_nodal_dof; ++d)
+ {
+ *interpolated_values[d] = 0.0;
+
+ for (unsigned n=0; n<num_nodes; ++n)
+ {
+ *interpolated_values[d] += nodal_values[d*num_nodes+n] * shape_matrix_N(n);
+ }
+ }
+}
+
+}
+
+#endif // NUMLIB_INTERPOLATION_H
--
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