Add unit test for generated 1d Lagrange shape functions

Author: nmnobre

tests/Makefile.am

@@ -44,6 +44,7 @@ unit_tests_sources = \
   fe/fe_test.h \
   fe/fe_xyz_test.C \
   fe/dual_shape_verification_test.C \
+  fe/fe_lagrange_shape_verification_test.C \
   geom/bbox_test.C \
   geom/edge_test.C \
   geom/elem_test.C \

tests/fe/fe_lagrange_shape_verification_test.C

@@ -0,0 +1,51 @@
+// libmesh includes
+#include "libmesh/libmesh.h"
+#include "libmesh/fe_lagrange_shape_1D.h"
+
+// unit test includes
+#include "test_comm.h"
+
+#include "libmesh_cppunit.h"
+
+using namespace libMesh;
+
+/**
+ * This class is for unit testing lagrange shape function values and derivatives
+ */
+class LagrangeShapeTest : public CppUnit::TestCase
+{
+public:
+
+  LIBMESH_CPPUNIT_TEST_SUITE( LagrangeShapeTest );
+  CPPUNIT_TEST( test1DLagrange );
+  CPPUNIT_TEST_SUITE_END();
+
+public:
+
+  void test1DLagrange ()
+  {
+    LOG_UNIT_TEST;
+
+    // TOLERANCE*TOLERANCE works with double but not float128
+    Real my_tol = TOLERANCE*std::sqrt(TOLERANCE);
+
+    for (auto xi : {0., 1./3., -.5, -1./7.})
+      for(auto o : make_range(1, 4))
+        for(auto i : make_range(o + 1))
+        {
+          LIBMESH_ASSERT_FP_EQUAL(fe_lagrange_1D_shape(Order(o), i, xi),
+                                  fe_lagrange_1D_any_shape(Order(o), i, xi), my_tol);
+          LIBMESH_ASSERT_FP_EQUAL(fe_lagrange_1D_shape_deriv(Order(o), i, 0, xi),
+                                  fe_lagrange_1D_any_shape_deriv(Order(o), i, 0, xi), my_tol);
+          LIBMESH_ASSERT_FP_EQUAL(fe_lagrange_1D_shape_second_deriv(Order(o), i, 0, xi),
+                                  fe_lagrange_1D_any_shape_second_deriv(Order(o), i, 0, xi), my_tol);
+        }
+  }
+
+  void setUp() {}
+
+  void tearDown() {}
+
+};
+
+CPPUNIT_TEST_SUITE_REGISTRATION( LagrangeShapeTest );