From c14688d249097ee0a1d6a13832ab2926f781da76 Mon Sep 17 00:00:00 2001
From: Daniel Arndt <daniel.arndt@iwr.uni-heidelberg.de>
Date: Fri, 17 Aug 2018 15:14:25 +0200
Subject: [PATCH] SolverQMRS

---
 include/deal.II/lac/solver_qmrs.h |  2 +-
 tests/cuda/solver_08.cu           | 85 +++++++++++++++++++++++++++++++
 tests/cuda/solver_08.output       |  6 +++
 3 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 tests/cuda/solver_08.cu
 create mode 100644 tests/cuda/solver_08.output

diff --git a/include/deal.II/lac/solver_qmrs.h b/include/deal.II/lac/solver_qmrs.h
index 7edd90ca64..824412cb12 100644
--- a/include/deal.II/lac/solver_qmrs.h
+++ b/include/deal.II/lac/solver_qmrs.h
@@ -457,7 +457,7 @@ SolverQMRS<VectorType>::iterate(const MatrixType &        A,
       // Double and vector updates
       rho               = u * r;
       const double beta = rho / rho_old;
-      q.sadd(beta, u);
+      q.sadd(beta, 1., u);
     }
   return IterationResult(SolverControl::success, res);
 }
diff --git a/tests/cuda/solver_08.cu b/tests/cuda/solver_08.cu
new file mode 100644
index 0000000000..0cd8caab52
--- /dev/null
+++ b/tests/cuda/solver_08.cu
@@ -0,0 +1,85 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2018 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// The deal.II library is free software; you can use it, redistribute
+// it, and/or modify it under the terms of the GNU Lesser General
+// Public License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+// The full text of the license can be found in the file LICENSE.md at
+// the top level directory of deal.II.
+//
+// ---------------------------------------------------------------------
+
+// Check that dealii::SolverQMRS works with CUDAWrappers::SparseMatrix
+
+#include <deal.II/base/cuda.h>
+#include <deal.II/base/exceptions.h>
+
+#include <deal.II/lac/cuda_sparse_matrix.h>
+#include <deal.II/lac/precondition.h>
+#include <deal.II/lac/read_write_vector.h>
+#include <deal.II/lac/solver_control.h>
+#include <deal.II/lac/solver_qmrs.h>
+#include <deal.II/lac/vector.h>
+
+#include "../testmatrix.h"
+#include "../tests.h"
+
+void
+test(Utilities::CUDA::Handle &cuda_handle)
+{
+  // Build the sparse matrix on the host
+  const unsigned int   problem_size = 10;
+  unsigned int         size         = (problem_size - 1) * (problem_size - 1);
+  FDMatrix             testproblem(problem_size, problem_size);
+  SparsityPattern      structure(size, size, 5);
+  SparseMatrix<double> A;
+  testproblem.five_point_structure(structure);
+  structure.compress();
+  A.reinit(structure);
+  testproblem.five_point(A);
+
+  // Solve on the host
+  PreconditionIdentity prec_no;
+  SolverControl        control(1000, 1.e-3);
+  SolverQMRS<>         qmrs_host(control);
+  Vector<double>       sol_host(size);
+  Vector<double>       rhs_host(size);
+  for (unsigned int i = 0; i < size; ++i)
+    rhs_host[i] = static_cast<double>(i);
+  qmrs_host.solve(A, sol_host, rhs_host, prec_no);
+
+  // Solve on the device
+  CUDAWrappers::SparseMatrix<double>          A_dev(cuda_handle, A);
+  LinearAlgebra::CUDAWrappers::Vector<double> sol_dev(size);
+  LinearAlgebra::CUDAWrappers::Vector<double> rhs_dev(size);
+  LinearAlgebra::ReadWriteVector<double>      rw_vector(size);
+  for (unsigned int i = 0; i < size; ++i)
+    rw_vector[i] = static_cast<double>(i);
+  rhs_dev.import(rw_vector, VectorOperation::insert);
+  SolverQMRS<LinearAlgebra::CUDAWrappers::Vector<double>> qmrs_dev(control);
+  qmrs_dev.solve(A_dev, sol_dev, rhs_dev, prec_no);
+
+  // Check the result
+  rw_vector.import(sol_dev, VectorOperation::insert);
+  for (unsigned int i = 0; i < size; ++i)
+    AssertThrow(std::fabs(rw_vector[i] - sol_host[i]) < 1e-8,
+                ExcInternalError());
+}
+
+int
+main()
+{
+  initlog();
+  deallog.depth_console(0);
+
+  Utilities::CUDA::Handle cuda_handle;
+  test(cuda_handle);
+
+  deallog << "OK" << std::endl;
+
+  return 0;
+}
diff --git a/tests/cuda/solver_08.output b/tests/cuda/solver_08.output
new file mode 100644
index 0000000000..67d21b185a
--- /dev/null
+++ b/tests/cuda/solver_08.output
@@ -0,0 +1,6 @@
+
+DEAL:SQMR::Starting value 416.989
+DEAL:SQMR::Convergence step 22 value 0.000879597
+DEAL:SQMR::Starting value 416.989
+DEAL:SQMR::Convergence step 22 value 0.000879597
+DEAL::OK
-- 
2.39.5