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D.13.1.19 faceContaining

Procedure from library gfan.lib (see gfan_lib).

Usage:
faceContaining(c,w); c cone, w intvec/bigintmat

Assume:
containsInSupport(c,w)==1

Return:
cone, the face of c containing w in its relative interior

Example:
 
LIB "gfan.lib";
intmat M[2][2]=
1,0,
0,1;
cone c=coneViaPoints(M);
faceContaining(c,intvec(1,0));
==> AMBIENT_DIM
==> 2
==> INEQUALITIES
==> 1,0
==> LINEAR_SPAN
==> 0,1
==> 
faceContaining(c,intvec(0,1));
==> AMBIENT_DIM
==> 2
==> INEQUALITIES
==> 0,1
==> LINEAR_SPAN
==> 1,0
==> 
faceContaining(c,intvec(1,1));
==> AMBIENT_DIM
==> 2
==> INEQUALITIES
==> 0,1,
==> 1,0
==> LINEAR_SPAN
==> 
==> 
faceContaining(c,intvec(0,0));
==> AMBIENT_DIM
==> 2
==> INEQUALITIES
==> 
==> LINEAR_SPAN
==> 1,0,
==> 0,1
==>