/* PQ.H
xref:
input:
output: stdout
does    - priority queue (PQ).
        - allows several PQ's.
*/
/************************************************************/

typedef struct
 {
  double a;     /* left */
  double b;     /* right */
  double i;     /* estimate */
  double e;     /*  error estimate */
  double v;     /* |error estimate| */

  }  INTERVAL;   /* integration interval */


typedef INTERVAL PQITEM;        /* PQ item = interval */

typedef struct
 {
  int n, maxn;            /*  size, max size */
  PQITEM* q;              /* pointer to queue items */
 }  PQDESC;               /* PQ descriptor */

typedef PQDESC* PQUEUE;


PQUEUE  pq_construct (int maxn);
void    pq_destruct  (PQUEUE p);
int     pq_insert    (PQUEUE p, PQITEM x);
PQITEM  pq_remove    (PQUEUE p);
PQITEM  pq_replace   (PQUEUE p, PQITEM x);