TAPP as interpreter backend

CMakeLists.txt

@@ -129,6 +129,8 @@ option(SEQUANT_BTAS "Enable BTAS eval backend" ${SEQUANT_EVAL_TESTS})
 add_feature_info(SEQUANT_EVAL_BTAS SEQUANT_BTAS "Enable BTAS eval backend")
 option(SEQUANT_TILEDARRAY "Enable TiledArray eval backend" ${SEQUANT_EVAL_TESTS})
 add_feature_info(SEQUANT_EVAL_TILEDARRAY SEQUANT_TILEDARRAY "Enable TiledArray eval backend")
+option(SEQUANT_TAPP "Enable TAPP eval backend" ${SEQUANT_EVAL_TESTS})
+add_feature_info(SEQUANT_EVAL_TAPP SEQUANT_TAPP "Enable TAPP eval backend")
 
 option(SEQUANT_IWYU "Whether to use the include-what-you-use tool (if found)" OFF)
 option(SEQUANT_WARNINGS_AS_ERRORS "Whether to treat compiler warnings as errors" ${PROJECT_IS_TOP_LEVEL})
@@ -460,6 +462,14 @@ set(SeQuant_eval_btas_src
         SeQuant/core/eval/backends/btas/result.hpp
 )
 
+# TAPP backend sources (header-only)
+set(SeQuant_eval_tapp_src
+        SeQuant/core/eval/backends/tapp/tensor.hpp
+        SeQuant/core/eval/backends/tapp/ops.hpp
+        SeQuant/core/eval/backends/tapp/eval_expr.hpp
+        SeQuant/core/eval/backends/tapp/result.hpp
+)
+
 # Core sources (just version info)
 set(SeQuant_core_src
         ${PROJECT_BINARY_DIR}/SeQuant/version.hpp
@@ -486,6 +496,12 @@ if (SEQUANT_BTAS)
     endif()
     set(SEQUANT_HAS_BTAS ON)
 endif ()
+if (SEQUANT_TAPP)
+    if (NOT TARGET tapp::reference)
+        include(FindOrFetchTAPP)
+    endif()
+    set(SEQUANT_HAS_TAPP ON)
+endif ()
 
 if (NOT PROJECT_IS_TOP_LEVEL)
     set(SEQUANT_SYSTEM "SYSTEM")
@@ -578,6 +594,17 @@ if (SEQUANT_HAS_BTAS)
     target_compile_definitions(SeQuant-eval-btas INTERFACE SEQUANT_HAS_BTAS=1)
 endif()
 
+##########################
+# SeQuant-eval-tapp: TAPP backend (header-only)
+##########################
+if (SEQUANT_HAS_TAPP)
+    add_library(SeQuant-eval-tapp INTERFACE)
+    set_target_properties(SeQuant-eval-tapp PROPERTIES EXPORT_NAME eval::tapp)
+    add_library(SeQuant::eval::tapp ALIAS SeQuant-eval-tapp)
+    target_link_libraries(SeQuant-eval-tapp INTERFACE SeQuant-eval SeQuant-symb tapp::reference)
+    target_compile_definitions(SeQuant-eval-tapp INTERFACE SEQUANT_HAS_TAPP=1)
+endif()
+
 ##########################
 # SeQuant-export: code generation/export (depends on eval)
 ##########################
@@ -616,6 +643,9 @@ endif()
 if (SEQUANT_HAS_BTAS)
     list(APPEND SEQUANT_MODULES SeQuant-eval-btas)
 endif()
+if (SEQUANT_HAS_TAPP)
+    list(APPEND SEQUANT_MODULES SeQuant-eval-tapp)
+endif()
 
 ##########################
 # SeQuant: umbrella INTERFACE target (backwards compatibility)

SeQuant/core/eval/backends/btas/result.hpp

@@ -210,7 +210,6 @@ class ResultTensorBTAS final : public Result {
 
  private:
   [[nodiscard]] std::size_t size_in_bytes() const final {
-    static_assert(std::is_arithmetic_v<typename T::value_type>);
     const auto& tensor = get<T>();
     // only count data
     return tensor.range().volume() * sizeof(T);

SeQuant/core/eval/backends/tapp/eval_expr.hpp

@@ -0,0 +1,64 @@
+#ifndef SEQUANT_EVAL_BACKENDS_TAPP_EVAL_EXPR_HPP
+#define SEQUANT_EVAL_BACKENDS_TAPP_EVAL_EXPR_HPP
+
+#ifdef SEQUANT_HAS_TAPP
+
+#include <SeQuant/core/eval/eval_expr.hpp>
+
+#include <SeQuant/core/container.hpp>
+#include <SeQuant/core/hash.hpp>
+#include <SeQuant/core/index.hpp>
+
+#include <range/v3/view.hpp>
+
+#include <cstdint>
+
+namespace sequant {
+
+///
+/// \brief This class extends the EvalExpr class by adding an annot() method so
+///        that it can be used to evaluate using TAPP.
+///
+class EvalExprTAPP final : public EvalExpr {
+ public:
+  using annot_t = container::svector<int64_t>;
+
+  ///
+  /// \param bk iterable of Index objects.
+  /// \return vector of int64_t-type hash values
+  ///         of the labels of indices in \c bk
+  ///
+  template <typename Iterable>
+  static auto index_hash(Iterable&& bk) {
+    return ranges::views::transform(
+        std::forward<Iterable>(bk), [](auto const& idx) {
+          return static_cast<int64_t>(sequant::hash::value(Index{idx}.label()));
+        });
+  }
+
+  template <typename... Args, typename = std::enable_if_t<
+                                  std::is_constructible_v<EvalExpr, Args...>>>
+  EvalExprTAPP(Args&&... args) : EvalExpr{std::forward<Args>(args)...} {
+    annot_ = index_hash(canon_indices()) | ranges::to<annot_t>;
+  }
+
+  ///
+  /// \return Annotation (container::svector<int64_t>) for TAPP tensors.
+  ///
+  [[nodiscard]] inline annot_t const& annot() const noexcept { return annot_; }
+
+ private:
+  annot_t annot_;
+};
+
+/// Type alias for TAPP evaluation nodes
+using EvalNodeTAPP = EvalNode<EvalExprTAPP>;
+
+static_assert(meta::eval_node<EvalNodeTAPP>);
+static_assert(meta::can_evaluate<EvalNodeTAPP>);
+
+}  // namespace sequant
+
+#endif  // SEQUANT_HAS_TAPP
+
+#endif  // SEQUANT_EVAL_BACKENDS_TAPP_EVAL_EXPR_HPP