enumerate-balanced-ideals/thickenings.h

#ifndef THICKENINGS_H
#define THICKENINGS_H

#include "coxeter.h"

#define DEBUG(msg, ...) do{fprintf(stderr, msg, ##__VA_ARGS__); }while(0)

#define MAX_THICKENINGS 0 // 0 means infinite
#define HEAD_MARKER 127

typedef struct _edgelist {
  int to;
  struct _edgelist *next;
} edgelist_t;

// describes an element of the Coxeter group; only "opposite" and "bruhat_lower" are being used for enumerating thickenings; everything else is just needed for initialization or output
typedef struct {
  int *word;
  int wordlength;
  int *left;
  int *right;
  int opposite;
  edgelist_t *bruhat_lower;
  edgelist_t *bruhat_higher;
  int is_hyperplane_reflection; // boolean value
} node_t;

// printing functions
char *alphabetize(int *word, int len, const char *alphabet, char *buffer);
void print_thickening(int rank, int order, const signed char *thickening, int level, const char *alphabet, FILE *f);

// generating the graph of the bruhat order
void prepare_graph(semisimple_type_t type, node_t *graph);
int prepare_simplified_graph(semisimple_type_t type, unsigned long left, unsigned long right, node_t *simplified_graph);

// enumerate balanced thickenings
long enumerate_balanced_thickenings(semisimple_type_t type, node_t *graph, int size, const char *alphabet, FILE *outfile);
node_t *graph_alloc(semisimple_type_t type);
void graph_free(semisimple_type_t type, node_t *graph);

// various helper functions
static int compare_wordlength(const void *a, const void *b, void *gr);
static int edgelist_contains(edgelist_t *list, int x);
static edgelist_t *edgelist_add(edgelist_t *list, int new, edgelist_t *storage, int *storage_index);

#endif