base/tensor.h add two static asserts

Take over Wolfgang's static_assert from pull request #9685

Co-authored-by: Wolfgang Bangerth <bangerth@colostate.edu>

diff --git a/include/deal.II/base/tensor.h b/include/deal.II/base/tensor.h
index a45d3ff217d8899a6941f4a4472f5ca0093beef5..3f1844d1f4ee28251384b98910b15b3bd3292ac4 100644 (file)
--- a/include/deal.II/base/tensor.h
+++ b/include/deal.II/base/tensor.h
@@ -93,6 +93,9 @@ template <int dim, typename Number>
 class Tensor<0, dim, Number>
 {
 public:
+  static_assert(dim >= 0,
+                "Tensors must have a dimension greater than or equal to one.");
+
   /**
    * Provide a way to get the dimension of an object without explicit
    * knowledge of it's data type. Implementation is this way instead of
@@ -414,6 +417,10 @@ template <int rank_, int dim, typename Number>
 class Tensor
 {
 public:
+  static_assert(rank_ >= 0,
+                "Tensors must have a rank greater than or equal to one.");
+  static_assert(dim >= 0,
+                "Tensors must have a dimension greater than or equal to one.");
   /**
    * Provide a way to get the dimension of an object without explicit
    * knowledge of it's data type. Implementation is this way instead of