#ifndef BSPLINES_AND_GRID_H
#define BSPLINES_AND_GRID_H

// coordinates in Bohr radii
#define GRID_START_POINT 0.0 
#define GRID_END_POINT 30.0
#define GRID_NUM_STEPS 300

typedef struct Grid Grid;
struct Grid 
{
  F64 start;
  F64 end;
  U32 num_steps;
  F64 *points;
};

typedef struct BSplineCtx BSplineCtx;
struct BSplineCtx 
{
  Arena* arena;
  U32 order;
  F64 *knotpoints;
  U32 num_knotpoints;
  U32 num_bsplines;
  U32 num_phys_points;
  F64 *bsplines_grid; // In grid points
  F64 *dBsplines_grid; // First deriv in grid points
  F64 *bsplines; // In knotpoints
  F64 *dBsplines; // First deriv in knotpoints
};

function void set_up_grid(Arena *arena);
//~ Bspline functions
function F64 bspline_recursion(F64 x, U32 k, U32 i);
function F64 compute_bspline_F64(F64 x_coord, U32 index);
function F64 compute_dBspline_F64(F64 x_coord, U32 index);
function inline U32 get_bspline_index_size(U32 size1, U32 i, U32 j);
function inline U32 get_bspline_index(U32 i, U32 j);
function inline U32 get_bspline_grid_index(U32 i, U32 j);
function void set_up_bspline_context(Arena* arena);
function void write_bspline_matrix_F64(F64 *bsplines, U32 size1, U32 size2, String8 filename_path);
function void set_up_bsplines_at_points_and_write_matrix_F64(Arena *arena);

#endif /* BSPLINES_AND_GRID_H */