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/*
* positioned_tet.c
*
* This file provides the following functions for working with PositionedTets:
*
* void veer_left(PositionedTet *ptet);
* void veer_right(PositionedTet *ptet);
* void veer_backwards(PositionedTet *ptet);
* Boolean same_positioned_tet(PositionedTet *ptet0, PositionedTet *ptet1);
* void set_left_edge(EdgeClass *edge, PositionedTet *ptet);
*
* Their use is described in kernel_prototypes.h.
*/
#include "kernel.h"
void veer_left(
PositionedTet *ptet)
{
Permutation left_gluing;
FaceIndex temp;
left_gluing = ptet->tet->gluing[ptet->left_face];
ptet->tet = ptet->tet->neighbor[ptet->left_face];
temp = ptet->near_face;
ptet->near_face = EVALUATE(left_gluing, ptet->left_face);
ptet->left_face = EVALUATE(left_gluing, temp);
ptet->right_face = EVALUATE(left_gluing, ptet->right_face);
ptet->bottom_face = EVALUATE(left_gluing, ptet->bottom_face);
if (parity[left_gluing] == orientation_reversing)
ptet->orientation = ! ptet->orientation;
}
void veer_right(
PositionedTet *ptet)
{
Permutation right_gluing;
FaceIndex temp;
right_gluing = ptet->tet->gluing[ptet->right_face];
ptet->tet = ptet->tet->neighbor[ptet->right_face];
temp = ptet->near_face;
ptet->near_face = EVALUATE(right_gluing, ptet->right_face);
ptet->right_face = EVALUATE(right_gluing, temp);
ptet->left_face = EVALUATE(right_gluing, ptet->left_face);
ptet->bottom_face = EVALUATE(right_gluing, ptet->bottom_face);
if (parity[right_gluing] == orientation_reversing)
ptet->orientation = ! ptet->orientation;
}
void veer_backwards(
PositionedTet *ptet)
{
Permutation near_gluing;
FaceIndex temp;
near_gluing = ptet->tet->gluing[ptet->near_face];
ptet->tet = ptet->tet->neighbor[ptet->near_face];
temp = ptet->left_face;
ptet->left_face = EVALUATE(near_gluing, ptet->right_face);
ptet->right_face = EVALUATE(near_gluing, temp);
ptet->near_face = EVALUATE(near_gluing, ptet->near_face);
ptet->bottom_face = EVALUATE(near_gluing, ptet->bottom_face);
if (parity[near_gluing] == orientation_reversing)
ptet->orientation = ! ptet->orientation;
}
Boolean same_positioned_tet(
PositionedTet *ptet0,
PositionedTet *ptet1)
{
return (
ptet0->tet == ptet1->tet
&& ptet0->near_face == ptet1->near_face
&& ptet0->left_face == ptet1->left_face
&& ptet0->right_face == ptet1->right_face);
/*
* If three faces match, so must the fourth, and so must the orientation.
*/
}
void set_left_edge(
EdgeClass *edge,
PositionedTet *ptet)
{
ptet->tet = edge->incident_tet;
ptet->near_face = one_face_at_edge[edge->incident_edge_index];
ptet->left_face = other_face_at_edge[edge->incident_edge_index];
ptet->right_face = remaining_face[ptet->left_face][ptet->near_face];
ptet->bottom_face = remaining_face[ptet->near_face][ptet->left_face];
ptet->orientation = right_handed;
}
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