From 3eb0fcb9fcdbfedf9937206921f605141c2e7a2d Mon Sep 17 00:00:00 2001
From: Baptiste Legouix <stilynx51@gmail.com>
Date: Fri, 17 May 2024 16:21:48 +0200
Subject: [PATCH] Splines small classes doc (#431)

---
 include/ddc/kernels/splines/deriv.hpp         |  4 +++
 .../ddc/kernels/splines/ginkgo_executors.hpp  |  6 ++++
 .../splines/spline_boundary_conditions.hpp    | 30 ++++++++++++++-----
 3 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/include/ddc/kernels/splines/deriv.hpp b/include/ddc/kernels/splines/deriv.hpp
index 70ebe619c..1562c9491 100644
--- a/include/ddc/kernels/splines/deriv.hpp
+++ b/include/ddc/kernels/splines/deriv.hpp
@@ -6,6 +6,10 @@
 
 namespace ddc {
 
+/**
+ * @brief A templated struct representing a discrete dimension storing
+ * the derivatives of a function along a continuous dimension Tag.
+ */
 template <class Tag>
 struct Deriv
 {
diff --git a/include/ddc/kernels/splines/ginkgo_executors.hpp b/include/ddc/kernels/splines/ginkgo_executors.hpp
index f720a07f9..a5feedced 100644
--- a/include/ddc/kernels/splines/ginkgo_executors.hpp
+++ b/include/ddc/kernels/splines/ginkgo_executors.hpp
@@ -13,6 +13,9 @@
 
 namespace ddc::detail {
 
+/**
+ * @brief A helper returning a ginkgo executor associated to Kokkos::DefaultHostExecutionSpace().
+ */
 inline std::shared_ptr<gko::Executor> create_default_host_executor()
 {
 #ifdef KOKKOS_ENABLE_SERIAL
@@ -27,6 +30,9 @@ inline std::shared_ptr<gko::Executor> create_default_host_executor()
 #endif
 } // Comes from "Basic Kokkos Extension" Ginkgo MR
 
+/**
+ * @brief A helper returning a ginkgo executor associated to Kokkos::DefaultExecutionSpace().
+ */
 template <typename ExecSpace>
 std::shared_ptr<gko::Executor> create_gko_exec()
 {
diff --git a/include/ddc/kernels/splines/spline_boundary_conditions.hpp b/include/ddc/kernels/splines/spline_boundary_conditions.hpp
index 743f30ae8..85a49f0c7 100644
--- a/include/ddc/kernels/splines/spline_boundary_conditions.hpp
+++ b/include/ddc/kernels/splines/spline_boundary_conditions.hpp
@@ -8,16 +8,24 @@
 #include <stdexcept>
 
 namespace ddc {
+
+/** @brief An enum representing a spline boundary condition. Please refer to
+ * Emily Bourne's thesis (https://www.theses.fr/2022AIXM0412.pdf)
+ */
 enum class BoundCond {
-    // Periodic boundary condition u(1)=u(n)
-    PERIODIC,
-    // Hermite boundary condition
-    HERMITE,
-    // Use Greville points instead of conditions on derivative for B-Spline
-    // interpolation
-    GREVILLE,
+    PERIODIC, ///< Periodic boundary condition u(1)=u(n)
+    HERMITE, ///< Hermite boundary condition
+    GREVILLE, ///< Use Greville points instead of conditions on derivative for B-Spline interpolation
 };
 
+/**
+ * @brief Prints a boundary condition in a std::ostream.
+ *
+ * @param out The stream in which the boundary condition is printed.
+ * @param degree The boundary condition.
+ *
+ * @return The stream in which the boundary condition is printed.
+ **/
 static inline std::ostream& operator<<(std::ostream& out, ddc::BoundCond const bc)
 {
     switch (bc) {
@@ -32,6 +40,14 @@ static inline std::ostream& operator<<(std::ostream& out, ddc::BoundCond const b
     }
 }
 
+/**
+ * @brief Return the number of equations needed to describe a given boundary condition.
+ *
+ * @param bc The boundary condition.
+ * @param degree The degree of the spline.
+ *
+ * @return The number of equations.
+ **/
 constexpr int n_boundary_equations(ddc::BoundCond const bc, std::size_t const degree)
 {
     if (bc == ddc::BoundCond::PERIODIC) {