added eddy current model and test

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include/Astro/eddyCurrentModel.hpp

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+/*
+ * Copyright (c) 
+ */
+
+#ifndef ASTRO_EDDY_CURRENT_HPP
+#define ASTRO_EDDY_CURRENT_HPP
+
+#include <SML/linearAlgebra.hpp>
+
+namespace astro
+{
+
+//! Compute eddy current torque.
+/*!
+ * Computes the eddy current torque on a certain object generated by an external source. The model
+ * for the torque is given by
+ *
+ * \f[
+ *      \vec{T}_{eddy} = \vec{m} \times \vec{B}
+ * \f]
+ * 
+ * where \f$\vec{m}\f$ is the magnetic moment of the object and \f$\vec{B}\f$ is the magnetic field
+ * generated by an external source.
+ *      
+ * @param  magneticMoment    Magnetic Moment         [A * m^2]
+ * @param  magneticField     Magnetic Field          [T]
+ * @return                   Eddy Current Torque     [N * m]                     
+ */
+ template< typename Vector3 >
+ Vector3 computeEddyTorque( const Vector3&  magneticMoment, 
+                            const Vector3&  magneticField ); 
+
+  //! Compute eddy current torque.
+ template< typename Vector3 >
+  Vector3 computeEddyTorque( const Vector3&  magneticMoment, 
+                             const Vector3&  magneticField )
+
+ {
+    // Compute the eddy current torque.
+    return sml::cross< Vector3 >( magneticMoment, magneticField);
+ }
+
+ } // namespace astro
+
+ #endif // ASTRO_EDDY_CURRENT_HPP

test/testEddyTorqueModel.cpp

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+/*
+ * Copyright (c) 
+ */
+#include <cmath>
+
+#include <vector>
+
+#include <catch.hpp>
+
+#include <Astro/eddyCurrentModel.hpp>
+
+using namespace std;
+
+namespace astro
+{
+
+namespace tests
+{
+
+typedef double Real;
+typedef std::vector< Real > Vector3;
+
+TEST_CASE( "Obtain eddy current torque: test 1", "[obtain-eddy-torque-1]" )
+{
+    // Set expected eddy current torque vector [N * m].
+    Vector3 expectedEddyTorque( 3 );
+    expectedEddyTorque[ 0 ] =  0.095000000000000;
+    expectedEddyTorque[ 1 ] =  0.065000000000000;
+    expectedEddyTorque[ 2 ] = -0.149000000000000;
+
+    // Set magnetic moment vector [A * m^2].
+    Vector3 magneticMoment( 3 );
+    magneticMoment[ 0 ] = 100.0;
+    magneticMoment[ 1 ] = 1000.0;
+    magneticMoment[ 2 ] = 500.0;
+
+    // Set magnetic field vector [T].
+    Vector3 magneticField( 3 );
+    magneticField[ 0 ] = 150e-6;
+    magneticField[ 1 ] = 10e-6;
+    magneticField[ 2 ] = 100e-6;
+
+    // Set epsilon = error between expected value and computed value.
+    const Real epsilon = 1.0e-10;
+
+     //! Compute eddy current torque.
+    const Vector3 eddyTorque = computeEddyTorque( magneticMoment, 
+                                                  magneticField ); 
+
+    // Check if computed torque matches expected value.
+    REQUIRE( std::fabs(eddyTorque[ 0 ] - expectedEddyTorque[ 0 ]) <= epsilon );
+    REQUIRE( std::fabs(eddyTorque[ 1 ] - expectedEddyTorque[ 1 ]) <= epsilon );
+    REQUIRE( std::fabs(eddyTorque[ 2 ] - expectedEddyTorque[ 2 ]) <= epsilon );
+}
+
+TEST_CASE( "Obtain eddy current torque: test 2", "[obtain-eddy-torque-2]" )
+{
+    // Set expected eddy current torque vector [N * m].
+    Vector3 expectedEddyTorque( 3 );
+    expectedEddyTorque[ 0 ] = 0.0;
+    expectedEddyTorque[ 1 ] = 0.0;
+    expectedEddyTorque[ 2 ] = 0.0;
+
+    // Set magnetic moment vector [A * m^2].
+    Vector3 magneticMoment( 3 );
+    magneticMoment[ 0 ] = 0.0;
+    magneticMoment[ 1 ] = 0.0;
+    magneticMoment[ 2 ] = 1150.0;
+
+    // Set magnetic field vector [T].
+    Vector3 magneticField( 3 );
+    magneticField[ 0 ] = 0.0;
+    magneticField[ 1 ] = 0.0;
+    magneticField[ 2 ] = 127e-6;
+
+    // Set epsilon = error between expected value and computed value.
+    const Real epsilon = 1.0e-10;
+
+     //! Compute eddy current torque.
+    const Vector3 eddyTorque = computeEddyTorque( magneticMoment, 
+                                                  magneticField ); 
+
+    // Check if computed torque matches expected value.
+    REQUIRE( std::fabs(eddyTorque[ 0 ] - expectedEddyTorque[ 0 ]) <= epsilon );
+    REQUIRE( std::fabs(eddyTorque[ 1 ] - expectedEddyTorque[ 1 ]) <= epsilon );
+    REQUIRE( std::fabs(eddyTorque[ 2 ] - expectedEddyTorque[ 2 ]) <= epsilon );
+}
+
+
+} // namespace tests
+} // namespace astro