# Singular

#### D.13.1.45 fanViaCones

Procedure from library `gfan.lib` (see gfan_lib).

Usage:
fanViaCones(L); L list
fanViaCones(c1[,...,ck]); c1,...,ck cones

Return:
fan, creates a fan generated by the cones in L resp c1,...,ck

Example:
 ```LIB "gfan.lib"; intmat M[2][2]=1,0,0,1; cone c=coneViaPoints(M); intmat N[2][2]=1,0,0,-1; cone d=coneViaPoints(N); fan f=fanViaCones(c,d); f; ==> _application PolyhedralFan ==> _version 2.2 ==> _type PolyhedralFan ==> ==> AMBIENT_DIM ==> 2 ==> ==> DIM ==> 2 ==> ==> LINEALITY_DIM ==> 0 ==> ==> RAYS ==> 0 -1 # 0 ==> 0 1 # 1 ==> 1 0 # 2 ==> ==> N_RAYS ==> 3 ==> ==> LINEALITY_SPACE ==> ==> ORTH_LINEALITY_SPACE ==> -1 0 # 0 ==> 0 -1 # 1 ==> ==> F_VECTOR ==> 1 3 2 ==> ==> SIMPLICIAL ==> 1 ==> ==> PURE ==> 1 ==> ==> CONES ==> {} # Dimension 0 ==> {0} # Dimension 1 ==> {1} ==> {2} ==> {0 2} # Dimension 2 ==> {1 2} ==> ==> MAXIMAL_CONES ==> {0 2} # Dimension 2 ==> {1 2} ==> list L=c,d; fan g=fanViaCones(L); g; ==> _application PolyhedralFan ==> _version 2.2 ==> _type PolyhedralFan ==> ==> AMBIENT_DIM ==> 2 ==> ==> DIM ==> 2 ==> ==> LINEALITY_DIM ==> 0 ==> ==> RAYS ==> 0 -1 # 0 ==> 0 1 # 1 ==> 1 0 # 2 ==> ==> N_RAYS ==> 3 ==> ==> LINEALITY_SPACE ==> ==> ORTH_LINEALITY_SPACE ==> -1 0 # 0 ==> 0 -1 # 1 ==> ==> F_VECTOR ==> 1 3 2 ==> ==> SIMPLICIAL ==> 1 ==> ==> PURE ==> 1 ==> ==> CONES ==> {} # Dimension 0 ==> {0} # Dimension 1 ==> {1} ==> {2} ==> {0 2} # Dimension 2 ==> {1 2} ==> ==> MAXIMAL_CONES ==> {0 2} # Dimension 2 ==> {1 2} ==> ```