89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
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#ifndef LATTICES_H
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#define LATTICES_H
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#include <math.h>
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#include <stdbool.h>
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#define M_SQRT3 1.7320508075688772935274463415058724
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// This might be reduced to x, y only; not sure yet
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typedef struct {
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double key; // distance key in a given lattice
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double x, y, r, phi;
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} point2d;
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static inline point2d point2d_fromxy(const double x, const double y) {
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point2d p;
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p.x = x;
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p.y = y;
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p.r = sqrt(x*x+y*y);
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p.phi = atan2(y, x);
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return p;
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}
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/*
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* General set of points ordered by the r-coordinate.
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* Typically, this will include all lattice inside a certain circle.
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* This structure is internally used by the "lattice generators" below.
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* It does not have its memory management of its own, as it is handled
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* by the "generators". For everything except the generators,
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* this structure shall be read-only.
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*/
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typedef struct {
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size_t nrs; // number of different radii
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double *rs; // the radii; of length nrs (largest contained radius == rs[nrs-1])
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point2d **points_at_r; // of length nrs+1
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/* // redundand (therefore removed) members
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* point2d *points; // redundant as it is the same as points_at_r[0]
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* size_t npoints; // redundant as it is the same as points_at_r[nrs]-points_at_r[0]
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*/
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} points2d_rordered_t;
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/*
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* EQUILATERAL TRIANGULAR LATTICE
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*/
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typedef enum {
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TRIANGULAR_VERTICAL, // there is a lattice base vector parallel to the y-axis
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TRIANGULAR_HORIZONTAL // there is a lattice base vector parallel to the x-axis
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} TriangularLatticeOrientation;
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// implementation data structures; not needed in the header file
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typedef struct triangular_lattice_gen_privstuff_t triangular_lattice_gen_privstuff_t;
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typedef struct {
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// public:
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points2d_rordered_t ps;
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TriangularLatticeOrientation orientation;
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double a; // lattice vector length
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// not sure if needed:
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bool includes_origin;
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// private:
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triangular_lattice_gen_privstuff_t *priv;
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} triangular_lattice_gen_t;
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triangular_lattice_gen_t *triangular_lattice_gen_init(double a, TriangularLatticeOrientation ori, bool include_origin);
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const points2d_reordered_t * triangular_lattice_gen_getpoints(const triangular lattice_generator_t *g);
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int triangular_lattice_gen_extend_to_r(triangular_lattice_generator_t *g, double r);
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int triangular_lattice_gen_extend_to_steps(triangular_lattice_generator_t *g, int maxsteps);
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void triangular_lattice_gen_free(triangular_lattice_generator_t *g);
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#if 0
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/*
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* HONEYCOMB LATTICE
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*/
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typedef struct {
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} honeycomb_lattice_generator_t;
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#endif
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#endif // LATTICES_H
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