Fix issues with very small and very big matrices

Author: Mikolaj Komar

include/dr/mp/containers/broadcasted_slim_matrix.hpp

@@ -51,8 +51,8 @@ class broadcasted_slim_matrix {
         rng::copy(root_data.begin(), root_data.end(), _data);
       }
     }
-    auto position = 0;
-    auto reminder = sizeof(T) * _data_size;
+    std::size_t position = 0;
+    std::size_t reminder = sizeof(T) * _data_size;
     while (reminder > INT_MAX) {
       comm.bcast(((uint8_t *)_data) + position, INT_MAX, root);
       position += INT_MAX;

include/dr/mp/containers/matrix_formats/csr_eq_distribution.hpp

@@ -63,7 +63,7 @@ class csr_eq_distribution {
       auto real_segment_size =
           std::min(nnz_ - rank * segment_size_, segment_size_);
       auto local_data = rows_data_;
-      auto division = real_segment_size / 50;
+      auto division = std::max(1ul, real_segment_size / 50);
       auto one_computation_size = (real_segment_size + division - 1) / division;
       auto row_size = row_size_;
       dr::__detail::parallel_for_workaround(