Merge pull request #1397 from moxcodes/cce_equations

Add CCE system equations

docs/References.bib

@@ -85,6 +85,21 @@ @article{Beckwith2011iy
   volume         = "193",
 }
 
+@article{Bishop1997ik,
+  author         = "Bishop, Nigel T. and Gomez, Roberto and Lehner, Luis and
+                    Maharaj, Manoj and Winicour, Jeffrey",
+  title          = "{High powered gravitational news}",
+  journal        = "Phys. Rev.",
+  volume         = "D56",
+  year           = "1997",
+  pages          = "6298-6309",
+  doi            = "10.1103/PhysRevD.56.6298",
+  eprint         = "gr-qc/9708065",
+  archivePrefix  = "arXiv",
+  primaryClass   = "gr-qc",
+  url            = "https://doi.org/10.1103/PhysRevD.56.6298",
+}
+
 @book{Cockburn1999,
   author     = "Cockburn, Bernardo",
   editor     = "Barth, Timothy J. and Deconinck, Herman",
@@ -298,6 +313,22 @@ @article{Hemberger2012jz
   primaryClass   = "gr-qc",
 }
 
+@article{Handmer2014qha,
+  author         = "Handmer, Casey J. and Szilagyi, B.",
+  title          = "{Spectral Characteristic Evolution: A New Algorithm for
+                    Gravitational Wave Propagation}",
+  journal        = "Class. Quant. Grav.",
+  volume         = "32",
+  year           = "2015",
+  number         = "2",
+  pages          = "025008",
+  doi            = "10.1088/0264-9381/32/2/025008",
+  eprint         = "1406.7029",
+  archivePrefix  = "arXiv",
+  primaryClass   = "gr-qc",
+  url            = "https://doi.org/10.1088/0264-9381/32/2/025008"
+}
+
 @book{Hartle2003gravity,
   author     = "Hartle, J.B.",
   title      = "Gravity: An Introduction to {Einstein's} General Relativity",

src/DataStructures/Tags.hpp

@@ -6,7 +6,9 @@
 #include <string>
 
 #include "DataStructures/DataBox/DataBoxTag.hpp"
+#include "DataStructures/SpinWeighted.hpp"
 #include "DataStructures/Tensor/Metafunctions.hpp"
+#include "DataStructures/Tensor/TypeAliases.hpp"
 
 /// \cond
 class DataVector;
@@ -40,4 +42,52 @@ struct Modal : db::SimpleTag, db::PrefixTag {
     return "Modal(" + NodalTag::name() + ")";
   }
 };
+
+/// Given a Tag with a `type` of `Tensor<VectorType, ...>`, acts as a new
+/// version of the tag with `type` of `Tensor<SpinWeighted<VectorType,
+/// SpinConstant::value>, ...>`, which is the preferred tensor type associated
+/// with spin-weighted quantities. Here, `SpinConstant` must be a
+/// `std::integral_constant` or similar type wrapper for a compile-time
+/// constant, in order to work properly with DataBox utilities.
+/// \note There are restrictions of which vector types can be wrapped
+/// by SpinWeighted in a Tensor, so some `Tag`s that have valid `type`s may
+/// give rise to compilation errors when used as `Tags::SpinWeighted<Tag,
+/// SpinConstant>`. If you find such trouble, consult the whitelist of possible
+/// Tensor storage types in `Tensor.hpp`.
+template <typename Tag, typename SpinConstant>
+struct SpinWeighted : db::PrefixTag, db::SimpleTag {
+  static_assert(not is_any_spin_weighted_v<typename Tag::type::type>,
+                "The SpinWeighted tag should only be used to create a "
+                "spin-weighted version of a non-spin-weighted tag. The "
+                "provided tag already has a spin-weighted type");
+  using type = TensorMetafunctions::swap_type<
+      ::SpinWeighted<typename Tag::type::type, SpinConstant::value>,
+      typename Tag::type>;
+  using tag = Tag;
+  static std::string name() noexcept {
+    return "SpinWeighted(" + Tag::name() + ", " +
+           std::to_string(SpinConstant::value) + ")";
+  }
+};
+
+namespace detail {
+template <typename LhsType, typename RhsType>
+using product_t =
+    Scalar<::SpinWeighted<ComplexDataVector,
+                          LhsType::type::spin + RhsType::type::spin>>;
+}  // namespace detail
+
+/// A prefix tag representing the product of two other tags. Note that if
+/// non-spin-weighted types are needed in this tag, the type alias
+/// `detail::product_t` should be generalized to give a reasonable type for
+/// those cases, or template specializations should be constructed for this tag.
+template <typename LhsTag, typename RhsTag>
+struct Multiplies : db::PrefixTag, db::SimpleTag {
+  using type = detail::product_t<db::item_type<LhsTag>, db::item_type<RhsTag>>;
+  using tag = LhsTag;
+  static std::string name() noexcept {
+    return "Multiplies(" + LhsTag::name() + ", " + RhsTag::name() + ")";
+  }
+};
+
 }  // namespace Tags

src/DataStructures/Variables.hpp

@@ -909,7 +909,7 @@ struct Subitems<TagList, Tag,
 
 namespace Tags {
 template <size_t N, typename T>
-struct TempTensor {
+struct TempTensor : db::SimpleTag {
   using type = T;
   static std::string name() noexcept {
     return std::string("TempTensor") + std::to_string(N);

src/Evolution/Systems/CMakeLists.txt

@@ -2,6 +2,7 @@
 # See LICENSE.txt for details.
 
 add_subdirectory(Burgers)
+add_subdirectory(Cce)
 add_subdirectory(CurvedScalarWave)
 add_subdirectory(GeneralizedHarmonic)
 add_subdirectory(GrMhd)

src/Evolution/Systems/Cce/CMakeLists.txt

@@ -0,0 +1,16 @@
+# Distributed under the MIT License.
+# See LICENSE.txt for details.
+
+set(LIBRARY Cce)
+
+set(LIBRARY_SOURCES
+  Equations.cpp
+  )
+
+add_spectre_library(${LIBRARY} ${LIBRARY_SOURCES})
+
+target_link_libraries(
+  ${LIBRARY}
+  INTERFACE DataStructures
+  INTERFACE ErrorHandling
+  )