remove virtual call in minres constructor + add test with preconditioner

clang tidy warns about using virtual calls in constructors, an explaination for that can be found here: https://wiki.sei.cmu.edu/confluence/display/cplusplus/OOP50-CPP.+Do+not+invoke+virtual+functions+from+constructors+or+destructors

include/ginkgo/core/solver/minres.hpp

@@ -170,13 +170,15 @@ class Minres : public EnableLinOp<Minres<ValueType>>,
         if (parameters_.generated_preconditioner) {
             GKO_ASSERT_EQUAL_DIMENSIONS(parameters_.generated_preconditioner,
                                         this);
-            set_preconditioner(parameters_.generated_preconditioner);
+            Preconditionable::set_preconditioner(
+                parameters_.generated_preconditioner);
         } else if (parameters_.preconditioner) {
-            set_preconditioner(
+            Preconditionable::set_preconditioner(
                 parameters_.preconditioner->generate(system_matrix_));
         } else {
-            set_preconditioner(matrix::Identity<ValueType>::create(
-                this->get_executor(), this->get_size()));
+            Preconditionable::set_preconditioner(
+                matrix::Identity<ValueType>::create(this->get_executor(),
+                                                    this->get_size()));
         }
         stop_criterion_factory_ =
             stop::combine(std::move(parameters_.criteria));

reference/test/solver/minres_kernels.cpp

@@ -39,6 +39,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <ginkgo/core/base/exception.hpp>
 #include <ginkgo/core/base/executor.hpp>
 #include <ginkgo/core/matrix/dense.hpp>
+#include <ginkgo/core/preconditioner/jacobi.hpp>
 #include <ginkgo/core/stop/combined.hpp>
 #include <ginkgo/core/stop/iteration.hpp>
 #include <ginkgo/core/stop/residual_norm.hpp>
@@ -94,6 +95,19 @@ class Minres : public ::testing::Test {
                       gko::stop::ResidualNorm<value_type>::build()
                           .with_reduction_factor(r<value_type>::value / 2)
                           .on(exec))
+                  .on(exec)),
+          preconditioned_minres_factory(
+              Solver::build()
+                  .with_criteria(
+                      gko::stop::Iteration::build().with_max_iters(40u).on(
+                          exec),
+                      gko::stop::ResidualNorm<value_type>::build()
+                          .with_reduction_factor(r<value_type>::value / 2)
+                          .on(exec))
+                  .with_preconditioner(
+                      gko::preconditioner::Jacobi<value_type>::build()
+                          .with_max_block_size(1u)
+                          .on(exec))
                   .on(exec))
     {
         stopped.stop(1);
@@ -135,6 +149,7 @@ class Minres : public ::testing::Test {
     gko::Array<gko::stopping_status> small_stop;
 
     std::unique_ptr<typename Solver::Factory> minres_factory;
+    std::unique_ptr<typename Solver::Factory> preconditioned_minres_factory;
 };
 
 TYPED_TEST_SUITE(Minres, gko::test::ValueTypes, TypenameNameGenerator);
@@ -308,4 +323,23 @@ TYPED_TEST(Minres, SolvesSystem)
 }
 
 
+TYPED_TEST(Minres, SolvesPreconditionedSystem)
+{
+    using Mtx = typename TestFixture::Mtx;
+    using vt = typename TestFixture::value_type;
+    auto one_op = gko::initialize<Mtx>({gko::one<vt>()}, this->exec);
+    auto neg_one_op = gko::initialize<Mtx>({-gko::one<vt>()}, this->exec);
+    auto solver = this->preconditioned_minres_factory->generate(this->mtx);
+    auto x = gko::initialize<Mtx>({-1., 2., 3., 4.}, this->exec);
+    auto sol = gko::clone(this->exec, x);
+    auto b = Mtx::create(this->exec, x->get_size());
+    this->mtx->apply(x.get(), b.get());
+    x->fill(0.);
+
+    solver->apply(b.get(), x.get());
+
+    GKO_ASSERT_MTX_NEAR(x, sol, r<vt>::value * 10);
+}
+
+
 }  // namespace

test/solver/minres_kernels.cpp

@@ -40,6 +40,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <ginkgo/core/base/exception.hpp>
 #include <ginkgo/core/base/executor.hpp>
 #include <ginkgo/core/matrix/dense.hpp>
+#include <ginkgo/core/preconditioner/jacobi.hpp>
 #include <ginkgo/core/stop/combined.hpp>
 #include <ginkgo/core/stop/iteration.hpp>
 #include <ginkgo/core/stop/residual_norm.hpp>
@@ -328,4 +329,48 @@ TEST_F(Minres, ApplyIsEquivalentToRef)
 }
 
 
+TEST_F(Minres, PreconditionedApplyIsEquivalentToRef)
+{
+
+    auto mtx = gen_mtx(50, 50, 53);
+    gko::test::make_hpd(mtx.get());
+    auto x = gen_mtx(50, 1, 5);
+    auto b = gen_mtx(50, 1, 4);
+    auto d_mtx = gko::clone(exec, mtx);
+    auto d_x = gko::clone(exec, x);
+    auto d_b = gko::clone(exec, b);
+    auto minres_factory =
+        gko::solver::Minres<value_type>::build()
+            .with_criteria(
+                gko::stop::Iteration::build().with_max_iters(400u).on(ref),
+                gko::stop::ResidualNorm<value_type>::build()
+                    .with_reduction_factor(::r<value_type>::value)
+                    .on(ref))
+            .with_preconditioner(
+                gko::preconditioner::Jacobi<value_type>::build()
+                    .with_max_block_size(1u)
+                    .on(ref))
+            .on(ref);
+    auto d_minres_factory =
+        gko::solver::Minres<value_type>::build()
+            .with_criteria(
+                gko::stop::Iteration::build().with_max_iters(400u).on(exec),
+                gko::stop::ResidualNorm<value_type>::build()
+                    .with_reduction_factor(::r<value_type>::value)
+                    .on(exec))
+            .with_preconditioner(
+                gko::preconditioner::Jacobi<value_type>::build()
+                    .with_max_block_size(1u)
+                    .on(exec))
+            .on(exec);
+    auto solver = minres_factory->generate(std::move(mtx));
+    auto d_solver = d_minres_factory->generate(std::move(d_mtx));
+
+    solver->apply(b.get(), x.get());
+    d_solver->apply(d_b.get(), d_x.get());
+
+    GKO_ASSERT_MTX_NEAR(d_x, x, ::r<value_type>::value * 100);
+}
+
+
 }  // namespace