Allow empty creation from all matrix formats convertible to CSR.

Author: pratikvn

core/solver/trs.cpp

@@ -45,6 +45,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "core/solver/trs_kernels.hpp"
 
+
 namespace gko {
 namespace solver {
 
@@ -68,11 +69,14 @@ void Trs<ValueType, IndexType>::generate(const LinOp *system_matrix,
     GKO_ASSERT_IS_SQUARE_MATRIX(system_matrix);
     // This is needed because it does not make sense to call the copy and
     // convert if the existing matrix (if not CSR) is empty.
-    if (dynamic_cast<const CsrMatrix *>(system_matrix) == nullptr) {
-        GKO_ASSERT_IS_NON_EMPTY_MATRIX(system_matrix);
-    }
     const auto exec = this->get_executor();
-    csr_system_matrix_ = copy_and_convert_to<CsrMatrix>(exec, system_matrix);
+    auto temp_cast = dynamic_cast<const CsrMatrix *>(system_matrix);
+    if (!system_matrix->get_size()) {
+        csr_system_matrix_ = CsrMatrix::create(exec);
+    } else {
+        csr_system_matrix_ =
+            copy_and_convert_to<CsrMatrix>(exec, system_matrix);
+    }
     auto dense_b = as<const Vector>(b);
     exec->run(trs::make_generate(gko::lend(csr_system_matrix_), dense_b));
 }

include/ginkgo/core/base/exception.hpp

@@ -281,9 +281,9 @@ class BadDimension : public Error {
      * @param line The source code line number where the error occurred
      * @param func The function name where the error occurred
      * @param op_name The name of the operator
-     * @param op_num_rows The output dimension of the operator
-     * @param op_num_cols The input dimension of the operator
-     * @param clarification An additional message describing the error further
+     * @param op_num_rows The row dimension of the operator
+     * @param op_num_cols The column dimension of the operator
+     * @param clarification An additional message further describing the error
      */
     BadDimension(const std::string &file, int line, const std::string &func,
                  const std::string &op_name, size_type op_num_rows,

reference/test/solver/trs.cpp

@@ -39,13 +39,15 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <gtest/gtest.h>
 
 
-#include <core/test/utils/assertions.hpp>
 #include <ginkgo/core/base/exception.hpp>
 #include <ginkgo/core/base/executor.hpp>
 #include <ginkgo/core/matrix/csr.hpp>
 #include <ginkgo/core/matrix/dense.hpp>
 
 
+#include "core/test/utils/assertions.hpp"
+
+
 namespace {
 
 
@@ -97,7 +99,7 @@ TEST_F(Trs, TrsFactoryCreatesCorrectSolver)
 
 TEST_F(Trs, CanBeCopied)
 {
-    auto copy = Solver::build().on(exec)->generate(CsrMtx::create(exec),
+    auto copy = Solver::build().on(exec)->generate(Mtx::create(exec),
                                                    Mtx::create(exec));
 
     copy->copy_from(lend(trs_solver));
@@ -112,7 +114,7 @@ TEST_F(Trs, CanBeCopied)
 
 TEST_F(Trs, CanBeMoved)
 {
-    auto copy = trs_factory->generate(CsrMtx::create(exec), Mtx::create(exec));
+    auto copy = trs_factory->generate(Mtx::create(exec), Mtx::create(exec));
 
     copy->copy_from(std::move(trs_solver));