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D.13.6.40 groebnerFan
Procedure from library tropical.lib (see tropical_lib).
- Usage:
- groebnerFan(f); f poly
groebnerFan(I); I ideal
- Assume:
- I homogeneous
- Return:
- fan, the Groebner fan of f resp. I
- Note:
- set printlevel=1 for output during traversal
Example:
| | LIB "tropical.lib";
ring r = 0,(x,y,z,w),dp;
ideal I = x-2y+3z,3y-4z+5w;
groebnerFan(I);
==> _application PolyhedralFan
==> _version 2.2
==> _type PolyhedralFan
==>
==> AMBIENT_DIM
==> 4
==>
==> DIM
==> 4
==>
==> LINEALITY_DIM
==> 1
==>
==> RAYS
==> -3 1 1 1 # 0
==> -1 -1 -1 3 # 1
==> -1 -1 3 -1 # 2
==> -1 3 -1 -1 # 3
==> 1 -3 1 1 # 4
==> 1 1 -3 1 # 5
==> 1 1 1 -3 # 6
==> 3 -1 -1 -1 # 7
==>
==> N_RAYS
==> 8
==>
==> LINEALITY_SPACE
==> -1 -1 -1 -1 # 0
==>
==> ORTH_LINEALITY_SPACE
==> 1 -1 0 0 # 0
==> 1 0 -1 0 # 1
==> 1 0 0 -1 # 2
==>
==> F_VECTOR
==> 1 8 12 6
==>
==> SIMPLICIAL
==> 0
==>
==> PURE
==> 1
==>
==> CONES
==> {} # Dimension 1
==> {0} # Dimension 2
==> {1}
==> {2}
==> {3}
==> {4}
==> {5}
==> {6}
==> {7}
==> {0 1} # Dimension 3
==> {0 2}
==> {0 3}
==> {1 4}
==> {2 4}
==> {1 5}
==> {2 6}
==> {3 5}
==> {3 6}
==> {4 7}
==> {5 7}
==> {6 7}
==> {0 1 2 4} # Dimension 4
==> {0 1 3 5}
==> {0 2 3 6}
==> {1 4 5 7}
==> {2 4 6 7}
==> {3 5 6 7}
==>
==> MAXIMAL_CONES
==> {0 1 2 4} # Dimension 4
==> {0 1 3 5}
==> {0 2 3 6}
==> {1 4 5 7}
==> {2 4 6 7}
==> {3 5 6 7}
==>
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