adding back files to be reviewed

include/openmc/distribution_spatial.h

@@ -0,0 +1,81 @@
+#ifndef OPENMC_DISTRIBUTION_SPATIAL_H
+#define OPENMC_DISTRIBUTION_SPATIAL_H
+
+#include "pugixml.hpp"
+
+#include "openmc/distribution.h"
+#include "openmc/position.h"
+
+namespace openmc {
+
+//==============================================================================
+//! Probability density function for points in Euclidean space
+//==============================================================================
+
+class SpatialDistribution {
+public:
+  virtual ~SpatialDistribution() = default;
+
+  //! Sample a position from the distribution
+  virtual Position sample() const = 0;
+};
+
+//==============================================================================
+//! Distribution of points specified by independent distributions in x,y,z
+//==============================================================================
+
+class CartesianIndependent : public SpatialDistribution {
+public:
+  explicit CartesianIndependent(pugi::xml_node node);
+
+  //! Sample a position from the distribution
+  //! \return Sampled position
+  Position sample() const;
+private:
+  UPtrDist x_; //!< Distribution of x coordinates
+  UPtrDist y_; //!< Distribution of y coordinates
+  UPtrDist z_; //!< Distribution of z coordinates
+};
+
+//==============================================================================
+//! Uniform distribution of points over a box
+//==============================================================================
+
+class SpatialBox : public SpatialDistribution {
+public:
+  explicit SpatialBox(pugi::xml_node node, bool fission=false);
+
+  //! Sample a position from the distribution
+  //! \return Sampled position
+  Position sample() const;
+
+  // Properties
+  bool only_fissionable() const { return only_fissionable_; }
+private:
+  Position lower_left_; //!< Lower-left coordinates of box
+  Position upper_right_; //!< Upper-right coordinates of box
+  bool only_fissionable_ {false}; //!< Only accept sites in fissionable region?
+};
+
+//==============================================================================
+//! Distribution at a single point
+//==============================================================================
+
+class SpatialPoint : public SpatialDistribution {
+public:
+  SpatialPoint() : r_{} { };
+  SpatialPoint(Position r) : r_{r} { };
+  explicit SpatialPoint(pugi::xml_node node);
+
+  //! Sample a position from the distribution
+  //! \return Sampled position
+  Position sample() const;
+private:
+  Position r_; //!< Single position at which sites are generated
+};
+
+using UPtrSpace = std::unique_ptr<SpatialDistribution>;
+
+} // namespace openmc
+
+#endif // OPENMC_DISTRIBUTION_SPATIAL_H