quiver.h

   1 /*
   2  * Copyright (c) 2018, S. Gilles <sgilles@math.umd.edu>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software
   5  * for any purpose with or without fee is hereby granted, provided
   6  * that the above copyright notice and this permission notice appear
   7  * in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
  10  * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
  11  * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
  12  * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
  13  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
  14  * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  15  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  16  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 /* A rational number */
  20 struct rational {
  21         /* Numerator */
  22         int_fast8_t p;
  23
  24         /* Denominator */
  25         uint_fast8_t q;
  26 };
  27
  28 /* The structure for a vertex */
  29 struct vertex {
  30         /* A textual identifier for this vertex */
  31         char *name;
  32
  33         /* Whether this vertex is `fat' or not. Expected to be 1, 2, or 3. */
  34         uint_fast8_t fatness;
  35
  36         /* Drawing data: coordinates in `internal coordinates */
  37         int x;
  38         int y;
  39
  40         /* Drawing data: color */
  41         uint_fast8_t r;
  42         uint_fast8_t g;
  43         uint_fast8_t b;
  44 };
  45
  46 /* The cluster algebra structure */
  47 struct quiver {
  48         /* How many vertices there actually are in the quiver */
  49         size_t v_num;
  50
  51         /* How many vertices we have allocated memory for */
  52         size_t v_len;
  53
  54         /* Vertices */
  55         struct vertex *v;
  56
  57         /* Edges - e_{ij} (fatness included, so E^t is not necessarily -E) */
  58         struct rational *e;
  59
  60         /* For detecting if quiver_mutate() creates an edge too high */
  61         unsigned int edge_weight_threshold;
  62 };
  63
  64 /* Add an arrow of weight a/b from i -> j, affecting e(i,j) and e(j,i) */
  65 int
  66 quiver_add_to_edge(struct quiver *q, size_t i, size_t j, int_fast8_t a,
  67                    uint_fast8_t b, const char **out_errstr);
  68
  69 /* Add a vertex with a name and weight */
  70 int
  71 quiver_add_vertex(struct quiver *q, size_t *out_i, const char *name,
  72                   uint_fast16_t fatness, int x, int y, uint32_t argb, const
  73                   char **out_errstr);
  74
  75 /* Increase or decrease the fatness of a vertex, readjusting edges as well */
  76 int
  77 quiver_adjust_fatness(struct quiver *q, size_t i, int_fast8_t fatness, const
  78                       char **out_errstr);
  79
  80 /* Free all memory used by this quiver, resetting it to { 0 } */
  81 int
  82 quiver_clean(struct quiver *q);
  83
  84 /* Delete a vertex (and all associated edges) */
  85 int
  86 quiver_delete_vertex(struct quiver *q, size_t i, const char **out_errstr);
  87
  88 /* Return σ_{ij} */
  89 int
  90 quiver_get_sigma(const struct quiver * const q, size_t i, size_t j, struct rational *out_s);
  91
  92 /* Read quiver from file */
  93 int
  94 quiver_load_from_file(struct quiver *q, FILE *f, const char **out_errstr);
  95
  96 /* Rename a vertex */
  97 int
  98 quiver_rename_vertex(struct quiver *q, size_t i, const char *new_name, const
  99                      char **out_errstr);
 100
 101 /* Recolor a vertex */
 102 int
 103 quiver_color_vertex(struct quiver *q, size_t i, uint32_t argb, const
 104                     char **out_errstr);
 105
 106 /* Serialize the quiver */
 107 int
 108 quiver_save_to_file(struct quiver *q, FILE *f, const char **out_errstr);
 109
 110 /* Set threshold: if quiver_mutate() creates an edge above, warn_out is set */
 111 int
 112 quiver_set_warning_threshold(struct quiver *q, unsigned int warn_threshold,
 113                              const char **out_errstr);
 114
 115 /* Mutate the quiver at vertex k, setting warn_out if threshold is broken */
 116 int
 117 quiver_mutate(struct quiver *q, size_t k, int *out_warn, const
 118               char **out_errstr);