#4669 Compute stress gradient.

ApplicationCode/GeoMech/GeoMechDataModel/RigHexGradientTools.h

@@ -0,0 +1,43 @@
+/////////////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (C) 2020-     Equinor ASA
+//
+//  ResInsight is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
+//  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.
+//
+//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
+//  for more details.
+//
+/////////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include "RigHexGradientTools.h"
+
+#include "cvfVector3.h"
+
+#include <array>
+
+//==================================================================================================
+///
+//==================================================================================================
+
+class RigHexGradientTools
+{
+public:
+    static std::array<cvf::Vec3d, 8> gradients( const std::array<cvf::Vec3d, 8>& hexCorners,
+                                                const std::array<double, 8>&     values );
+
+private:
+    // Private to avoid instantiation
+    RigHexGradientTools();
+
+    static double forwardFD( const std::array<double, 8>& values, int from, int to );
+    static double backwardFD( const std::array<double, 8>& values, int from, int to );
+};