Clean up determinism test

tests/unit/fem/test_fa_determinism.cpp

@@ -0,0 +1,62 @@
+// Copyright (c) 2010-2022, Lawrence Livermore National Security, LLC. Produced
+// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
+// LICENSE and NOTICE for details. LLNL-CODE-806117.
+//
+// This file is part of the MFEM library. For more information and source code
+// availability visit https://mfem.org.
+//
+// MFEM is free software; you can redistribute it and/or modify it under the
+// terms of the BSD-3 license. We welcome feedback and contributions, see file
+// CONTRIBUTING.md for details.
+
+#include "mfem.hpp"
+#include "unit_tests.hpp"
+
+using namespace mfem;
+
+TEST_CASE("FA Determinism", "[PartialAssembly][CUDA]")
+{
+   const int order = 3;
+   const char *mesh_filename = "../../data/star-q3.mesh";
+
+   Mesh mesh = Mesh::LoadFromFile(mesh_filename);
+
+   const int dim = mesh.Dimension();
+
+   H1_FECollection fec(order, dim);
+   FiniteElementSpace fes(&mesh, &fec);
+
+   Vector x, b_reference;
+
+   const int ntrials = 100 + 1;
+   for (int i = 0; i < ntrials; ++i)
+   {
+      BilinearForm a(&fes);
+      a.AddDomainIntegrator(new DiffusionIntegrator);
+      a.SetAssemblyLevel(AssemblyLevel::FULL);
+      a.Assemble();
+      a.Finalize();
+
+      SparseMatrix &A = a.SpMat();
+      const int n = A.Height();
+
+      if (x.Size() == 0)
+      {
+         x.SetSize(n);
+         x.Randomize(1);
+      }
+
+      Vector b(n);
+      A.Mult(x, b);
+
+      if (b_reference.Size() == 0)
+      {
+         b_reference = b;
+      }
+      else
+      {
+         b -= b_reference;
+         REQUIRE(b.Normlinf() == 0.0);
+      }
+   }
+}