remove gsl-lite dependence

.gitmodules

@@ -1,9 +1,6 @@
 [submodule "vendor/pugixml"]
 	path = vendor/pugixml
 	url = https://github.com/zeux/pugixml.git
-[submodule "vendor/gsl-lite"]
-	path = vendor/gsl-lite
-	url = https://github.com/martinmoene/gsl-lite.git
 [submodule "vendor/xtensor"]
 	path = vendor/xtensor
 	url = https://github.com/xtensor-stack/xtensor.git

CMakeLists.txt

@@ -274,19 +274,6 @@ if (NOT xtensor_FOUND)
   add_subdirectory(vendor/xtensor)
 endif()
 
-#===============================================================================
-# GSL header-only library
-#===============================================================================
-
-find_package_write_status(gsl-lite)
-if (NOT gsl-lite_FOUND)
-  add_subdirectory(vendor/gsl-lite)
-
-  # Make sure contract violations throw exceptions
-  target_compile_definitions(gsl-lite-v1 INTERFACE GSL_THROW_ON_CONTRACT_VIOLATION)
-  target_compile_definitions(gsl-lite-v1 INTERFACE gsl_CONFIG_ALLOWS_NONSTRICT_SPAN_COMPARISON=1)
-endif()
-
 #===============================================================================
 # Catch2 library
 #===============================================================================
@@ -499,7 +486,7 @@ endif()
 # target_link_libraries treats any arguments starting with - but not -l as
 # linker flags. Thus, we can pass both linker flags and libraries together.
 target_link_libraries(libopenmc ${ldflags} ${HDF5_LIBRARIES} ${HDF5_HL_LIBRARIES}
-                      xtensor gsl::gsl-lite-v1 fmt::fmt ${CMAKE_DL_LIBS})
+                      xtensor fmt::fmt ${CMAKE_DL_LIBS})
 
 if(TARGET pugixml::pugixml)
   target_link_libraries(libopenmc pugixml::pugixml)

MANIFEST.in

@@ -43,6 +43,5 @@ recursive-include vendor *.hh
 recursive-include vendor *.hpp
 recursive-include vendor *.pc.in
 recursive-include vendor *.natvis
-include vendor/gsl-lite/include/gsl/gsl
 prune docs/build
 prune docs/source/pythonapi/generated/

cmake/OpenMCConfig.cmake.in

@@ -1,7 +1,6 @@
 get_filename_component(OpenMC_CMAKE_DIR "${CMAKE_CURRENT_LIST_FILE}" DIRECTORY)
 
 find_package(fmt REQUIRED HINTS ${OpenMC_CMAKE_DIR}/../fmt)
-find_package(gsl-lite REQUIRED HINTS ${OpenMC_CMAKE_DIR}/../gsl-lite)
 find_package(pugixml REQUIRED HINTS ${OpenMC_CMAKE_DIR}/../pugixml)
 find_package(xtl REQUIRED HINTS ${OpenMC_CMAKE_DIR}/../xtl)
 find_package(xtensor REQUIRED HINTS ${OpenMC_CMAKE_DIR}/../xtensor)
@@ -41,4 +40,4 @@ endif()
 
 if(@OPENMC_USE_UWUW@ AND NOT ${DAGMC_BUILD_UWUW})
   message(FATAL_ERROR "UWUW is enabled in OpenMC but the DAGMC installation discovered was not configured with UWUW.")
-endif()
+endif()

include/openmc/cell.h

@@ -10,7 +10,6 @@
 
 #include "hdf5.h"
 #include "pugixml.hpp"
-#include <gsl/gsl-lite.hpp>
 
 #include "openmc/bounding_box.h"
 #include "openmc/constants.h"
@@ -129,7 +128,7 @@ class Region {
   void add_precedence();
 
   //! Add parenthesis to enforce precedence
-  gsl::index add_parentheses(gsl::index start);
+  int64_t add_parentheses(int64_t start);
 
   //! Remove complement operators from the expression
   void remove_complement_ops();
@@ -415,8 +414,8 @@ struct CellInstance {
     return index_cell == other.index_cell && instance == other.instance;
   }
 
-  gsl::index index_cell;
-  gsl::index instance;
+  int64_t index_cell;
+  int64_t instance;
 };
 
 //! Structure necessary for inserting CellInstance into hashed STL data

include/openmc/distribution.h

@@ -7,10 +7,10 @@
 #include <cstddef> // for size_t
 
 #include "pugixml.hpp"
-#include <gsl/gsl-lite.hpp>
 
 #include "openmc/constants.h"
 #include "openmc/memory.h" // for unique_ptr
+#include "openmc/span.h"
 #include "openmc/vector.h" // for vector
 
 namespace openmc {
@@ -44,9 +44,9 @@ class DiscreteIndex {
 public:
   DiscreteIndex() {};
   DiscreteIndex(pugi::xml_node node);
-  DiscreteIndex(gsl::span<const double> p);
+  DiscreteIndex(span<const double> p);
 
-  void assign(gsl::span<const double> p);
+  void assign(span<const double> p);
 
   //! Sample a value from the distribution
   //! \param seed Pseudorandom number seed pointer

include/openmc/distribution_spatial.h

@@ -6,6 +6,7 @@
 #include "openmc/distribution.h"
 #include "openmc/mesh.h"
 #include "openmc/position.h"
+#include "openmc/span.h"
 
 namespace openmc {
 
@@ -104,7 +105,7 @@ class SphericalIndependent : public SpatialDistribution {
 class MeshSpatial : public SpatialDistribution {
 public:
   explicit MeshSpatial(pugi::xml_node node);
-  explicit MeshSpatial(int32_t mesh_id, gsl::span<const double> strengths);
+  explicit MeshSpatial(int32_t mesh_id, span<const double> strengths);
 
   //! Sample a position from the distribution
   //! \param seed Pseudorandom number seed pointer
@@ -144,7 +145,7 @@ class PointCloud : public SpatialDistribution {
 public:
   explicit PointCloud(pugi::xml_node node);
   explicit PointCloud(
-    std::vector<Position> point_cloud, gsl::span<const double> strengths);
+    std::vector<Position> point_cloud, span<const double> strengths);
 
   //! Sample a position from the distribution
   //! \param seed Pseudorandom number seed pointer

include/openmc/interpolate.h

@@ -4,10 +4,9 @@
 #include <cmath>
 #include <vector>
 
-#include <gsl/gsl-lite.hpp>
-
 #include "openmc/error.h"
 #include "openmc/search.h"
+#include "openmc/span.h"
 
 namespace openmc {
 
@@ -36,8 +35,8 @@ inline double interpolate_log_log(
   return y0 * std::exp(f * std::log(y1 / y0));
 }
 
-inline double interpolate_lagrangian(gsl::span<const double> xs,
-  gsl::span<const double> ys, int idx, double x, int order)
+inline double interpolate_lagrangian(
+  span<const double> xs, span<const double> ys, int idx, double x, int order)
 {
   double output {0.0};
 
@@ -56,9 +55,8 @@ inline double interpolate_lagrangian(gsl::span<const double> xs,
   return output;
 }
 
-inline double interpolate(gsl::span<const double> xs,
-  gsl::span<const double> ys, double x,
-  Interpolation i = Interpolation::lin_lin)
+inline double interpolate(span<const double> xs, span<const double> ys,
+  double x, Interpolation i = Interpolation::lin_lin)
 {
   int idx = lower_bound_index(xs.begin(), xs.end(), x);
 

include/openmc/material.h

@@ -4,9 +4,9 @@
 #include <string>
 #include <unordered_map>
 
+#include "openmc/span.h"
 #include "pugixml.hpp"
 #include "xtensor/xtensor.hpp"
-#include <gsl/gsl-lite.hpp>
 #include <hdf5.h>
 
 #include "openmc/bremsstrahlung.h"
@@ -118,21 +118,21 @@ class Material {
   //
   //! \param[in] density Density value
   //! \param[in] units Units of density
-  void set_density(double density, gsl::cstring_span units);
+  void set_density(double density, const std::string& units);
 
   //! Set temperature of the material
   void set_temperature(double temperature) { temperature_ = temperature; };
 
   //! Get nuclides in material
   //! \return Indices into the global nuclides vector
-  gsl::span<const int> nuclides() const
+  span<const int> nuclides() const
   {
     return {nuclide_.data(), nuclide_.size()};
   }
 
   //! Get densities of each nuclide in material
   //! \return Densities in [atom/b-cm]
-  gsl::span<const double> densities() const
+  span<const double> densities() const
   {
     return {atom_density_.data(), atom_density_.size()};
   }
@@ -210,7 +210,7 @@ class Material {
 
   //----------------------------------------------------------------------------
   // Private data members
-  gsl::index index_;
+  int64_t index_;
 
   bool depletable_ {false}; //!< Is the material depletable?
   bool fissionable_ {

include/openmc/mcpl_interface.h

@@ -2,10 +2,9 @@
 #define OPENMC_MCPL_INTERFACE_H
 
 #include "openmc/particle_data.h"
+#include "openmc/span.h"
 #include "openmc/vector.h"
 
-#include <gsl/gsl-lite.hpp>
-
 #include <string>
 
 namespace openmc {
@@ -36,7 +35,7 @@ vector<SourceSite> mcpl_source_sites(std::string path);
 //!                         calculate_parallel_index_vector on
 //!                         source_bank.size().
 void write_mcpl_source_point(const char* filename,
-  gsl::span<SourceSite> source_bank, vector<int64_t> const& bank_index);
+  span<const SourceSite> source_bank, const vector<int64_t>& bank_index);
 } // namespace openmc
 
 #endif // OPENMC_MCPL_INTERFACE_H

include/openmc/mesh.h

@@ -9,13 +9,13 @@
 #include "hdf5.h"
 #include "pugixml.hpp"
 #include "xtensor/xtensor.hpp"
-#include <gsl/gsl-lite.hpp>
 
 #include "openmc/bounding_box.h"
 #include "openmc/error.h"
 #include "openmc/memory.h" // for unique_ptr
 #include "openmc/particle.h"
 #include "openmc/position.h"
+#include "openmc/span.h"
 #include "openmc/vector.h"
 #include "openmc/xml_interface.h"
 
@@ -174,8 +174,8 @@ class Mesh {
   //! \param[out] Array of (material index, volume) for desired element
   //! \param[inout] seed Pseudorandom number seed
   //! \return Number of materials within element
-  int material_volumes(int n_sample, int bin, gsl::span<MaterialVolume> volumes,
-    uint64_t* seed) const;
+  int material_volumes(
+    int n_sample, int bin, span<MaterialVolume> volumes, uint64_t* seed) const;
 
   //! Determine volume of materials within a single mesh elemenet
   //

include/openmc/nuclide.h

@@ -7,7 +7,6 @@
 #include <unordered_map>
 #include <utility> // for pair
 
-#include <gsl/gsl-lite.hpp>
 #include <hdf5.h>
 
 #include "openmc/array.h"
@@ -17,6 +16,7 @@
 #include "openmc/particle.h"
 #include "openmc/reaction.h"
 #include "openmc/reaction_product.h"
+#include "openmc/span.h"
 #include "openmc/urr.h"
 #include "openmc/vector.h"
 #include "openmc/wmp.h"
@@ -81,8 +81,8 @@ class Nuclide {
   //! \param[in] energy Energy group boundaries in [eV]
   //! \param[in] flux Flux in each energy group (not normalized per eV)
   //! \return Reaction rate
-  double collapse_rate(int MT, double temperature,
-    gsl::span<const double> energy, gsl::span<const double> flux) const;
+  double collapse_rate(int MT, double temperature, span<const double> energy,
+    span<const double> flux) const;
 
   //============================================================================
   // Data members
@@ -91,7 +91,7 @@ class Nuclide {
   int A_;            //!< Mass number
   int metastable_;   //!< Metastable state
   double awr_;       //!< Atomic weight ratio
-  gsl::index index_; //!< Index in the nuclides array
+  int64_t index_;    //!< Index in the nuclides array
 
   // Temperature dependent cross section data
   vector<double> kTs_;                //!< temperatures in eV (k*T)
@@ -138,7 +138,7 @@ class Nuclide {
   //
   //! \param[in] T Temperature in [K]
   //! \return Temperature index and interpolation factor
-  std::pair<gsl::index, double> find_temperature(double T) const;
+  std::pair<int64_t, double> find_temperature(double T) const;
 
   static int XS_TOTAL;
   static int XS_ABSORPTION;

include/openmc/photon.h

@@ -7,7 +7,6 @@
 #include "openmc/vector.h"
 
 #include "xtensor/xtensor.hpp"
-#include <gsl/gsl-lite.hpp>
 #include <hdf5.h>
 
 #include <string>
@@ -61,7 +60,7 @@ class PhotonInteraction {
   // Data members
   std::string name_; //!< Name of element, e.g. "Zr"
   int Z_;            //!< Atomic number
-  gsl::index index_; //!< Index in global elements vector
+  int64_t index_;    //!< Index in global elements vector
 
   // Microscopic cross sections
   xt::xtensor<double, 1> energy_;

include/openmc/reaction.h

@@ -7,10 +7,10 @@
 #include <string>
 
 #include "hdf5.h"
-#include <gsl/gsl-lite.hpp>
 
 #include "openmc/particle_data.h"
 #include "openmc/reaction_product.h"
+#include "openmc/span.h"
 #include "openmc/vector.h"
 
 namespace openmc {
@@ -33,7 +33,7 @@ class Reaction {
   //! \param[in] i_temp Temperature index
   //! \param[in] i_grid Energy grid index
   //! \param[in] interp_factor Interpolation factor between grid points
-  double xs(gsl::index i_temp, gsl::index i_grid, double interp_factor) const;
+  double xs(int64_t i_temp, int64_t i_grid, double interp_factor) const;
 
   //! Calculate cross section
   //
@@ -47,8 +47,8 @@ class Reaction {
   //! \param[in] flux Flux in each energy group (not normalized per eV)
   //! \param[in] grid Nuclide energy grid
   //! \return Reaction rate
-  double collapse_rate(gsl::index i_temp, gsl::span<const double> energy,
-    gsl::span<const double> flux, const vector<double>& grid) const;
+  double collapse_rate(int64_t i_temp, span<const double> energy,
+    span<const double> flux, const vector<double>& grid) const;
 
   //! Cross section at a single temperature
   struct TemperatureXS {