debug output

Author: gojakuch

core/distributed/preconditioner/schwarz.cpp

@@ -4,6 +4,7 @@
 
 #include "ginkgo/core/distributed/preconditioner/schwarz.hpp"
 
+#include <cmath>
 #include <memory>
 
 #include <ginkgo/core/base/exception_helpers.hpp>
@@ -232,6 +233,9 @@ void Schwarz<ValueType, LocalIndexType, GlobalIndexType>::generate(
         l1_diag->move_to(l1_diag_csr);
         l1_diag_csr->sort_by_column_index();  // spgeam requires sorting for
                                               // some backends
+        if (std::isnan(real(l1_diag_csr->get_const_values()[0]))) {  // DEBUG
+            throw std::string("l1_diag_csr nan value after sorting");
+        }
         auto id = matrix::Identity<ValueType>::create(
             exec, local_matrix->get_size()[0]);
         auto one = initialize<matrix::Dense<ValueType>>(