From: Bruno Turcksin <bruno.turcksin@gmail.com>
Date: Mon, 28 Oct 2024 15:16:32 +0000 (-0400)
Subject: Fix C++20 Tensor initialization
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F17744%2Fhead;p=dealii.git

Fix C++20 Tensor initialization
---

diff --git a/include/deal.II/base/tensor.h b/include/deal.II/base/tensor.h
index 40ba24ba1c..b7f2c0e530 100644
--- a/include/deal.II/base/tensor.h
+++ b/include/deal.II/base/tensor.h
@@ -1292,7 +1292,11 @@ Tensor<rank_, dim, Number>::Tensor()
       // returning a zero instead.
       []<std::size_t... I>(
         const std::index_sequence<I...> &) constexpr -> decltype(values) {
-        if constexpr (rank_ == 1)
+        if constexpr (dim == 0)
+          {
+            return {};
+          }
+        else if constexpr (rank_ == 1)
           {
             auto get_zero_and_ignore_argument = [](int) {
               return internal::NumberType<Number>::value(0.0);