/**
 *  @file canonize.h
 *  @brief Defines CONCAVITY_EPSILON for canonical triangulations.
 *
 *  In canonize_part_1.c, canonize_part_2.c, and canonize_result.c, the sum
 *  of the tilts of two Tetrahedra relative to their common face is
 *  considered to be zero iff it lies between -CONCAVITY_EPSILON and
 *  +CONCAVITY_EPSILON.
 *
 *  cusp_neighborhoods.c now includes this file as well, so it can
 *  supress the drawing of faces which serve only to subdivide the
 *  canonical cell decomposition into tetrahedra.
 */


/**
 *  The processing of the data for 16-crossing knots led to several
 *  examples which sometimes were reported to have canonical
 *  decompositions with cells other than tetrahedra, and sometimes
 *  not.  This led me to suspect that CONCAVITY_EPSILON was too big,
 *  so I changed it from 1e-6 to 1e-7.  (This problem hadn't arisen
 *  with snappea 1.3.x because the latter normalized cusp volumes to
 *  1.0, whereas SnapPea 2.x normalizes them to (3/16)sqrt(3).)
 *  Eventually I may need to adopt a more sophisticated approach to
 *  using CONCAVITY_EPSILON, somehow taking into account the volume of
 *  the cusp.
 */

#ifndef CONCAVITY_EPSILON
#define CONCAVITY_EPSILON   1e-7
#endif

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