#  Copyright (c) 1997-2024
#  Ewgenij Gawrilow, Michael Joswig, and the polymake team
#  Technische Universität Berlin, Germany
#  https://polymake.org
#
#  This program is free software; you can redistribute it and/or modify it
#  under the terms of the GNU General Public License as published by the
#  Free Software Foundation; either version 2, or (at your option) any
#  later version: http://www.gnu.org/licenses/gpl.txt.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#-------------------------------------------------------------------------------

object PolyhedralFan {

# to be overloaded in special cases like Scalar==Float
sub prepare_computations { undef }

# @category Geometry
# Dimension of the space which contains the polyhedral fan.
# Note: To avoid confusion in context of (in-)homogenuous coordinates it is generally advised to use the method [[AMBIENT_DIM]].
# @example The fan living in the plane containing only the cone which consists of the ray pointing in positive x-direction is
# by definition embedded in the plane:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0]],INPUT_CONES=>[[0]]);
# > print $f->FAN_AMBIENT_DIM;
# | 2

property FAN_AMBIENT_DIM : Int;


# @category Geometry
# Dimension of the polyhedral fan.
# # Note: To avoid confusion in context of (in-)homogenuous coordinates it is generally advised to use the method [[DIM]].
# @example The fan living in the plane containing only the cone which consists of the ray pointing in positive x-direction is
# 1-dimensional:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0]],INPUT_CONES=>[[0]]);
# > print $f->FAN_DIM;
# | 1

property FAN_DIM : Int;

# @category Combinatorics
# Combinatorial dimension of the fan.
# @example The [[normal_fan|normal fan]] of the 6-cube has combinatorial dimension 5:
# > print normal_fan(cube(6))->COMBINATORIAL_DIM;
# | 5

property COMBINATORIAL_DIM : Int;

# @category Geometry
# A fan is __full-dimensional__ if its [[FAN_DIM|dimension]] and [[FAN_AMBIENT_DIM|ambient dimension]] coincide.
# @example The [[normal_fan|normal fan]] of a polytope is always full-dimensional, which we see here for the 5-dimensional [[cross|cross polytope]]:
# > $nf = normal_fan(cross(5));
# > print $nf->FULL_DIM;
# | true

property FULL_DIM : Bool;

# @category Geometry
# A fan is __pointed__ if the [[LINEALITY_SPACE|lineality space]] is trivial.
# @example The [[normal_fan|normal fan]] of a polytope is pointed if and only if the polytope is full-dimensional. Here we confirm this for
# the normal fans of the 2-cube living in 2- and in 3-space, respectively:
# > $nf_full = normal_fan(cube(2));
# > print $nf_full->POINTED;
# | true
# > $nf_not_full = normal_fan(product(cube(2),new Polytope(POINTS=>[[1,0]])));
# > print $nf_not_full->POINTED;
# | false

property POINTED : Bool;

# @category Geometry
# Since we do not require our cones to be [[POINTED|pointed]]: a basis of the lineality space of the fan. Co-exists with [[RAYS]].
# @example We can create a fan in 3-space from the two 2-dimensional cones which are the (x,y)- and (x,z)-halfspaces where
# y and z are non-negative, respectively. Both cones and thus the fan contain lineality in x-direction:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0],[0,1,0],[0,0,1],[-1,0,0]],INPUT_CONES=>[[0,1,3],[0,2,3]]);
# > print $f->LINEALITY_SPACE;
# | 1 0 0

property LINEALITY_SPACE : Matrix<Scalar>;


# @category Geometry
# A basis of the orthogonal complement to [[LINEALITY_SPACE]].
# @example In 3-space, we build a fan containing only the ray pointing in positive x-direction, together with lineality in y-direction.
# The definition of the cones yields no additional lineality, thus the orthogonal complement to the lineality space is spanned
# by (1,0,0) and (0,0,1):
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0]],INPUT_CONES=>[[0]],INPUT_LINEALITY=>[[0,1,0]]);
# > print $f->ORTH_LINEALITY_SPACE;
# | 1 0 0
# | 0 0 1

property ORTH_LINEALITY_SPACE : Matrix<Scalar>;


# @category Geometry
# Dimension of the [[LINEALITY_SPACE|lineality space]].
# @example A [[POINTED|pointed]] fan has no lineality, thus the dimension of its lineality space is 0. The most simple example is a fan
# only consisting of one ray, here in the plane:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0]],INPUT_CONES=>[[0]]);
# > print $f->LINEALITY_DIM;
# | 0

property LINEALITY_DIM : Int;


# @category Input property
# Rays from which the cones are formed.  May be redundant. All vectors in the input must be non-zero.
# You also need to provide [[INPUT_CONES]] to define a fan completely.
# Input section only. Ask for [[RAYS]] if you want a list of non-redundant rays.
# @example When constructing the fan which displays the division of the plane into quadrants, we can use
# redundant rays such that the indices given in [[INPUT_CONES]] suggest that two rays form the border of our fan, but due
# to our choice in [[INPUT_RAYS]], they actually are the same ray adjacent to two distinct 2-dimensional cones:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0],[0,1],[-1,0],[0,-1],[2,0]],INPUT_CONES=>[[0,1],[1,2],[2,3],[3,4]]);
# > print rows_labeled($f->RAYS);
# | 0:1 0
# | 1:0 1
# | 2:-1 0
# | 3:0 -1
# > print $f->CONES;
# | <{0}
# | {1}
# | {2}
# | {3}
# | >
# | <{0 1}
# | {1 2}
# | {2 3}
# | {0 3}
# | >


property INPUT_RAYS : Matrix<Scalar>;


# @category Input property
# Maybe redundant list of not necessarily maximal cones.  Indices refer to [[INPUT_RAYS]].
# Each cone must list all rays of [[INPUT_RAYS]] it contains.
# Any incident cones will automatically be added.
# The cones are allowed to contain lineality.
# Cones which do not have any rays correspond to the trivial cone (contains only the origin).
# An empty fan does not have any cones.
# Input section only. Ask for [[MAXIMAL_CONES]] if you want to know the maximal cones (indexed by [[RAYS]]).
# @example In 3-space, we construct the fan containing the closure of the all-positive octant and the
# (x<=0, y>=0, z=0) quadrant with the following input (note that we do not have to state the combinatorics for
# cones contained in a given cone of higher dimension, e.g. the the (x>=0, z>=0) quadrant in the y=0 plane):
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0],[0,1,0],[0,0,1],[-1,0,0]],INPUT_CONES=>[[0,1,2],[1,3]]);
# > print rows_labeled($f->RAYS);
# | 0:1 0 0
# | 1:0 1 0
# | 2:0 0 1
# | 3:-1 0 0
# > print $f->CONES;
# | <{1}
# | {3}
# | {2}
# | {0}
# | >
# | <{1 3}
# | {1 2}
# | {0 2}
# | {0 1}
# | >
# | <{0 1 2}
# | >


property INPUT_CONES : IncidenceMatrix;

# @category Input property
# Vectors whose linear span defines a subset of the lineality space of the fan; 
# redundancies are allowed.
#
# Input section only.  Ask for [[LINEALITY_SPACE]] if you want to know the lineality space.
# @example In 3-space, we can "stretch" the (x>=0, y>=0) quadrant in the z=0 hyperplane to obtain the joint of the
# two octants where x and y are non-negative by adding linearity in z-direction:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0],[0,1,0]],INPUT_CONES=>[[0,1]],INPUT_LINEALITY=>[[0,0,1]]);

property INPUT_LINEALITY : Matrix<Scalar>;


# @category Geometry
# Rays of the [[PolyhedralFan]]. Non-redundant. Co-exists with [[LINEALITY_SPACE]].
# @example The rays of the [[face_fan|face fan]] of a 3-dimensioanl cube. This fan has one ray in the direcction of each vertex of the cube.
# > print face_fan(cube(3))->RAYS;
# | -1 -1 -1
# | 1 -1 -1
# | -1 1 -1
# | 1 1 -1
# | -1 -1 1
# | 1 -1 1
# | -1 1 1
# | 1 1 1

property RAYS : Matrix<Scalar> {
   sub canonical { &canonicalize_rays; }
}

# permuting the [[RAYS]]
permutation RaysPerm : PermBase;

rule RaysPerm.PERMUTATION : RaysPerm.RAYS, RAYS, LINEALITY_SPACE {
   my $cmp = $this->prepare_computations;
   $this->RaysPerm->PERMUTATION = find_representation_permutation($this->RaysPerm->RAYS, $this->RAYS, $this->LINEALITY_SPACE, 0)
      // die "no permutation";
}

rule RAYS : RaysPerm.RAYS, RaysPerm.PERMUTATION {
   $this->RAYS=permuted_rows($this->RaysPerm->RAYS, $this->RaysPerm->PERMUTATION);
}
weight 1.10;

# @category Geometry
# Number of [[RAYS]].
# @example The number of facets of a polytope is the number of rays of the corresponding [[normal_fan|normal fan]]. Here we see this for the 3-cube:
# > print normal_fan(cube(3))->N_RAYS;
# | 6

property N_RAYS : Int;

# @category Geometry
# Number of [[INPUT_RAYS]].
# @example To determine the combined amount of redundant and unused rays given by [[INPUT_RAYS]], we compare this number
# to [[N_RAYS]]:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0],[0,1],[-1,0],[0,-1],[2,0],[1,1]],INPUT_CONES=>[[0,1],[1,2],[2,3],[3,4]]);
# > print ($f->N_INPUT_RAYS-$f->N_RAYS);
# | 2

property N_INPUT_RAYS : Int;

# @category Combinatorics
# Non redundant list of maximal cones.  Indices refer to [[RAYS]].
# Cones which do not have any rays correspond to the trivial cone (contains only the origin).
# An empty fan does not have any cones.
# @example The maximal cones of the normal fan of the 3-cube describe which faces share a common vertex:
# > print normal_fan(cube(3))->MAXIMAL_CONES;
# | {0 2 4}
# | {1 2 4}
# | {0 3 4}
# | {1 3 4}
# | {0 2 5}
# | {1 2 5}
# | {0 3 5}
# | {1 3 5}

property MAXIMAL_CONES : IncidenceMatrix;

rule MAXIMAL_CONES : RaysPerm.MAXIMAL_CONES, RaysPerm.PERMUTATION {
   $this->MAXIMAL_CONES = permuted_cols($this->RaysPerm->MAXIMAL_CONES, $this->RaysPerm->PERMUTATION);
}

# permuting the [[MAXIMAL_CONES]]
permutation ConesPerm : PermBase;

rule ConesPerm.PERMUTATION : ConesPerm.MAXIMAL_CONES, MAXIMAL_CONES  {
   $this->ConesPerm->PERMUTATION = find_permutation(new Array<Set<Int>>(rows($this->ConesPerm->MAXIMAL_CONES)), new Array<Set<Int>>(rows($this->MAXIMAL_CONES)))
      // die "no permutation";
}
weight 1.10;


rule MAXIMAL_CONES : ConesPerm.MAXIMAL_CONES, ConesPerm.PERMUTATION {
   $this->MAXIMAL_CONES = permuted_rows($this->ConesPerm->MAXIMAL_CONES, $this->ConesPerm->PERMUTATION);
}
weight 1.10;

# @category Combinatorics
# Transposed to [[MAXIMAL_CONES]].
# Notice that this is a temporary property; it will not be stored in any file.
property MAXIMAL_CONES_THRU_RAYS : IncidenceMatrix;

rule MAXIMAL_CONES_THRU_RAYS : MAXIMAL_CONES {
    $this->MAXIMAL_CONES_THRU_RAYS(temporary)=transpose($this->MAXIMAL_CONES);
}


# @category Combinatorics
# List of all cones of the fan of each dimension.  Indices refer to [[RAYS]].
# @example A fan constructed with a 2-dimensional cone in [[INPUT_CONES]] also contains the incident 1-dimensional
# cones.
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0],[0,1]],INPUT_CONES=>[[0,1]]);
# > print $f->CONES;
# | <{0}
# | {1}
# | >
# | <{0 1}
# | >
property CONES : Array<IncidenceMatrix>;

# @category Combinatorics
# Number of [[MAXIMAL_CONES]].
# @example The number of facets of a polytope is the same as the number of maximal cones of its face fan;
# here we can see this for the 3-cube:
# > print face_fan(cube(3))->N_MAXIMAL_CONES;
# | 6
property N_MAXIMAL_CONES : Int;

# @category Combinatorics
# Number of [[CONES]].
property N_CONES : Int;

# @category Combinatorics
# Array of incidence matrices of all [[MAXIMAL_CONES|maximal cones]]. Indices refer to [[RAYS]].
# @example Here we construct a fan with a 3-dimensional and a 2-dimensional maximal cone and then display the incident cones:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0],[0,1,0],[0,0,1],[-1,0,0]],INPUT_CONES=>[[0,1,2],[1,3]]);
# > print $f->MAXIMAL_CONES;
# | {0 1 2}
# | {1 3}
# > print $f->MAXIMAL_CONES_INCIDENCES;
# | <{1 2}
# | {0 2}
# | {0 1}
# | >
# | <{1}
# | {3}
# | >

property MAXIMAL_CONES_INCIDENCES : Array<IncidenceMatrix>;

rule MAXIMAL_CONES_INCIDENCES : ConesPerm.MAXIMAL_CONES_INCIDENCES, ConesPerm.PERMUTATION {
   $this->MAXIMAL_CONES_INCIDENCES=permuted($this->ConesPerm->MAXIMAL_CONES_INCIDENCES, $this->ConesPerm->PERMUTATION);
}
weight 1.10;

rule MAXIMAL_CONES_INCIDENCES : RaysPerm.MAXIMAL_CONES_INCIDENCES, RaysPerm.PERMUTATION {
  my $n_mc=scalar(@{$this->RaysPerm->MAXIMAL_CONES_INCIDENCES});
  my $mci=new Array<IncidenceMatrix>($n_mc);
  foreach my $i (0..$n_mc-1) {
      $mci->[$i]=permuted_cols($this->RaysPerm->MAXIMAL_CONES_INCIDENCES->[$i], $this->RaysPerm->PERMUTATION);
    }
  $this->MAXIMAL_CONES_INCIDENCES=$mci;
}
weight 1.10;

# @category Combinatorics
# The combinatorial dimensions of the [[MAXIMAL_CONES|maximal cones]].
# @example Here we construct a fan with a 3-dimensional and a 2-dimensional maximal cone, of which the latter contains lineality,
# and then display the corresponding combinatorial dimensions:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0],[0,1,0],[0,0,1],[-1,0,0],[0,-1,0]],INPUT_CONES=>[[0,1,2],[1,3,4]]);
# > print $f->MAXIMAL_CONES;
# | {0 1 2}
# | {3}
# > print $f->MAXIMAL_CONES_COMBINATORIAL_DIMS;
# | 2 0

property MAXIMAL_CONES_COMBINATORIAL_DIMS : Array<Int>;

rule MAXIMAL_CONES_COMBINATORIAL_DIMS : ConesPerm.MAXIMAL_CONES_COMBINATORIAL_DIMS, ConesPerm.PERMUTATION {
   $this->MAXIMAL_CONES_COMBINATORIAL_DIMS=permuted($this->ConesPerm->MAXIMAL_CONES_COMBINATORIAL_DIMS, $this->ConesPerm->PERMUTATION);
}
weight 1.10;

# @category Combinatorics
# The combinatorial dimensions of the [[CONES|cones]].
property CONES_COMBINATORIAL_DIMS : Array<Int>;

rule CONES_COMBINATORIAL_DIMS : ConesPerm.CONES_COMBINATORIAL_DIMS, ConesPerm.PERMUTATION {
   $this->CONES_COMBINATORIAL_DIMS=permuted($this->ConesPerm->CONES_COMBINATORIAL_DIMS, $this->ConesPerm->PERMUTATION);
}
weight 1.10;


# @category Combinatorics
# The dimensions of the [[CONES|cones]].
# @return Array<Int>
user_method CONES_DIMS : FAN_DIM, CONES_COMBINATORIAL_DIMS {
    my $this=shift;
    my @mcd;
    my $cd=$this->COMBINATORIAL_DIM;
    my $d=0;
    if ( defined ($this->lookup( "RAYS | INPUT_RAYS | INPUT_LINEALITY | LINEALITY_SPACE | LINEALITY_DIM | FAN_DIM | FACET_NORMALS | ORTH_LINEALITY_SPACE" ) ) ) {
        $d=$this->FAN_DIM-$cd;
    }
    foreach (@{$this->CONES_COMBINATORIAL_DIMS}) {
        push @mcd, $_+$d;
    }
    return new Array<Int>(@mcd);
}


# @category Visualization
# Unique names assigned to the [[RAYS]].
# If specified, they are shown by visualization tools instead of vertex indices.
#
# For a polyhedral fan built from scratch, you should create this property by yourself,
# either manually in a text editor, or with a client program.
# @example The [[normal_fan|normal fan]] of the 2-cube has 4 rays; to assign the labels 'a', 'b' and 'any label' to the first
# three entries of [[RAYS]], do this (note that the unspecified label of the last ray is blank when visualizing, and that,
# depending on your visualization settings, not the whole string of the third label might be displayed):
# > $f = normal_fan(cube(2));
# > $f->RAY_LABELS=['a','b','any label'];

property RAY_LABELS : Array<String> : mutable;

rule RAY_LABELS : RaysPerm.RAY_LABELS, RaysPerm.PERMUTATION {
   $this->RAY_LABELS=permuted($this->RaysPerm->RAY_LABELS, $this->RaysPerm->PERMUTATION);
}
weight 1.10;

# @category Visualization
# Unique names assigned to the [[INPUT_RAYS]].  Similar to [[RAY_LABELS]] for [[RAYS]].

property INPUT_RAY_LABELS : Array<String> : mutable;

# @category Visualization
# Unique names assigned to the [[MAXIMAL_CONES]].  Similar to [[RAY_LABELS]] for [[RAYS]].

property MAXIMAL_CONE_LABELS : Array<String> : mutable;

# @category Combinatorics
# The poset of subcones of the polyhedral fan organized as a directed graph.
# Each node corresponds to some proper subcone of the fan.
# The nodes corresponding to the maximal cones appear in the same order
# as the elements of [[MAXIMAL_CONES]].
#
# One special node represents the origin and one special node represents the full fan
# (even if the fan only has one maximal cone).
# @example To compute the Hasse diagram of the [[normal_fan|normal fan]] of the 2-cube and display its
# decoration, we can do the following. Note the artificial node on top and the empty node at the bottom. The latter represents the trivial cone consisting only of the origin.
# > $h = normal_fan(cube(2))->HASSE_DIAGRAM;
# print $h->DECORATION;
# | ({-1} 3)
# | ({0 2} 2)
# | ({1 2} 2)
# | ({0 3} 2)
# | ({1 3} 2)
# | ({0} 1)
# | ({2} 1)
# | ({1} 1)
# | ({3} 1)
# | ({} 0)

property HASSE_DIAGRAM : Lattice<BasicDecoration> {

	method get_shift() {
		my $this = shift;
		return $this->parent->isa("fan::PolyhedralComplex") ? 1 : 0;
	}

   # @category Combinatorics
   # @return Int
   user_method dim {
		my $this = shift;
      return $this->rank() - $this->get_shift();
   }

   # @category Combinatorics
   # @param Int d dimension
   # @return Set<Int>
   user_method nodes_of_dim($) {
      my ($this,$d) = @_;
      return $this->nodes_of_rank($d + $this->get_shift());
   }

   # @category Combinatorics
   # @param Int d1 lower dimension
   # @param Int d1 upper dimension
   # @return Set<Int>
   user_method nodes_of_dim_range($,$) {
      my ($this,$d1,$d2) = @_;
		my $st = $this->get_shift();
      return shift->nodes_of_rank_range($d1+$st,$d2+$st);
   }

   method cones_of_dim($) {
      my ($this, $k) = @_;
      my $n = $this->nodes_of_rank(1)->size();
      my @rows = map { $this->DECORATION->[$_]->face } @{$this->nodes_of_rank($k)};
      return @rows ? new IncidenceMatrix(\@rows, $n) : new IncidenceMatrix(0, $n);
   }
                                                           
}

# @category Combinatorics
# f<sub>ik</sub> is the number of incident pairs of i-dimensional cones and k-dimensional cones; the main diagonal contains the [[F_VECTOR]].

property F2_VECTOR : Matrix<Integer>;


# @category Combinatorics
# f<sub>k</sub> is the number of k-dimensional cones starting from dimension k=1.
# The f-vector of a polytope and the f-vector of any of its [[face_fan|face fans]] coincide; for the 3-cube:
# > print face_fan(cube(3))->F_VECTOR;
# | 8 12 6

property F_VECTOR : Vector<Integer>;

# @category Combinatorics
# The polyhedral fan is __pure__ if all [[MAXIMAL_CONES|maximal cones]] are of the same dimension.
# @example Generating a fan from two distinct 2-dimensional cones gives a pure fan:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0],[0,1],[-1,0],[0,-1]],INPUT_CONES=>[[0,1],[2,3]]);
# > print $f->PURE;
# | true
# @example Gnerating a fan from a 2-dimensional and a 1-dimensional cone results in the fan not being pure if the latter is a ray
# not contained in the former:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,1],[-1,1],[0,-1]],INPUT_CONES=>[[0,1],[2]]);
# > print $f->PURE;
# | false

property PURE : Bool;

# @category Combinatorics
# The polyhedral fan is __complete__ if its suport is the whole space.
#
# Due to undecidability issues this is checked heuristically only.
# See the remarks on [[topaz::SimplicialComplex::SPHERE|SPHERE]] for details.
# Note that in the case of a polyhedral complex, this refers to the underlying fan, so should always be false.
# @example The [[normal_fan|normal fan]] of a polytope always is complete; here we see this for the 8-cube:
# > print normal_fan(cube(8))->COMPLETE;
# | true

property COMPLETE : Bool;


# @category Combinatorics
# The polyhedral fan is __simplicial__ if all [[MAXIMAL_CONES|maximal cones]] are [[Cone::SIMPLICIAL|simplicial]].
# @example The [[normal_fan|normal fan]] of a d-cube is __simplicial__; here we see this for the 3-cube:
# > print normal_fan(cube(3))->SIMPLICIAL;
# | true

property SIMPLICIAL : Bool;

# @category Geometry
# True if the fan is the [[normal_fan|normal fan]] of a [[Polytope::BOUNDED|bounded]] polytope.
# @example The [[face_fan|face fan]] of the centered d-dimensional cross polytope w.r.t. the origin 
# is the [[normal_fan|normal fan]] of the d-cube; here we confirm the regularity of the face fan for d=7:
# > print face_fan(cross(7))->REGULAR;
# | true
# @example A [[normal_fan|normal fan]] always is complete; thus a fan which is not complete can not be regular:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0],[0,1]],INPUT_CONES=>[[0,1]]);
# > print $f->REGULAR;
# | false

property REGULAR : Bool;

# @category Geometry
# True if the fan is a subfan of a [[REGULAR]] fan
# @example Here we build a fan in the plane with the non-negative quadrant and the ray pointing in negative y-direction
# as its [[MAXIMAL_CONES|maximal cones]]. This is a subfan of the fan with all four quadrants as its maximal cones which is the
# [[normal_fan|normal fan]] of the 2-cube; thus, our fan is pseudo regular:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0],[0,1],[-1,0]],INPUT_CONES=>[[0,1],[2]]);
# > print $f->PSEUDO_REGULAR;
# | true

property PSEUDO_REGULAR : Bool;

# @category Combinatorics
# The graph of the fan intersected with a sphere, that is,
# the vertices are the rays which are connected if they are
# contained in a common two-dimensional cone.
# @example The graph of a [[face_fan|face fan]] of a polytope is isomorphic to the vertex-edge graph of the polytope.
# Here we see this for the 3-cube:
# > $c = cube(3);
# > $f = face_fan($c);
# > $g1 = $f->GRAPH;
# > $g2 = $c->GRAPH;
# > print isomorphic($g1->ADJACENCY,$g2->ADJACENCY);
# | true

property GRAPH : Graph;

rule GRAPH.NodePerm.PERMUTATION = RaysPerm.PERMUTATION;

# @category Combinatorics
# The graph whose nodes are the maximal cones which
# are connected if they share a common facet.
# Only defined if [[PURE]].
# @example The dual graph of a [[face_fan|face fan]] of the 3-cube is isomorphic to the vertex-edge graph of the
# 3-dimensional cross polytope.
# > $c = cross(3);
# > $f = face_fan(cube(3));
# > $g1 = $f->DUAL_GRAPH;
# > $g2 = $c->GRAPH;
# > print isomorphic($g1->ADJACENCY,$g2->ADJACENCY);
# | true

property DUAL_GRAPH : Graph;

rule DUAL_GRAPH.NodePerm.PERMUTATION = ConesPerm.PERMUTATION;

# @category Geometry
# The possible facet normals of all maximal cones.
# @example The two facet normals of the complete fan dividing the plane into the four quadrants (which can be obtained by
# computing the [[normal_fan|normal fan]] of the 2-cube) point in x- and in y-direction, respectively:
# > print normal_fan(cube(2))->FACET_NORMALS;
# | 1 0
# | 0 1

property FACET_NORMALS : Matrix<Scalar>;

# @category Geometry
# The number of possible facet normals of all maximal cones.
# @example The facets of the [[normal_fan|normal fan]] of the 3-cube are each spanned by a ray pointing in positive or negative
# direction of one axis and another ray pointing in positive or negative direction of another axis; thus, the third axis
# is normal to this facet. This leaves us with three possible facet normals:
# > print normal_fan(cube(3))->N_FACET_NORMALS;
# | 3

property N_FACET_NORMALS : Int;

# @category Geometry
# Tells for each maximal cone what are its facet normals, thus implying the facets.
# Each row corresponds to a maximal cone and each column to the row with the same index of [[FACET_NORMALS]].
# A negative number means that the corresponding row of
# [[FACET_NORMALS]] has to be negated.
# @example The two facet normals of the complete fan dividing the plane into the four quadrants (which can be obtained by
# computing the [[normal_fan|normal fan]] of the 2-cube) point in x- and in y-direction, respectively. Each quadrant has both of these
# as normals only differing by the combination of how they point in- or outside:
# > $f = normal_fan(cube(2));
# > print $f->MAXIMAL_CONES;
# | {0 2}
# | {1 2}
# | {0 3}
# | {1 3}
# > print rows_numbered($f->FACET_NORMALS);
# | 0:1 0
# | 1:0 1
# > print $f->MAXIMAL_CONES_FACETS;
# | 1 1
# | -1 1
# | 1 -1
# | -1 -1

property MAXIMAL_CONES_FACETS : SparseMatrix<Int>;

rule MAXIMAL_CONES_FACETS : ConesPerm.MAXIMAL_CONES_FACETS, ConesPerm.PERMUTATION {
   $this->MAXIMAL_CONES_FACETS=permuted_rows($this->ConesPerm->MAXIMAL_CONES_FACETS, $this->ConesPerm->PERMUTATION);
}
weight 1.10;

# @category Geometry
# The possible linear span normals of all maximal cones.
# Empty if [[PURE]] and [[FULL_DIM]], i.e. each maximal cone has the same dimension as the ambient space.
# @example We construct a fan in 3-space with two 2-dimensional maximal cones and a 1-dimensional maximal cone. Note that
# there are two possible normals for the latter, but one of these also is a normal for one of the 2-dimensional cones; thus
# we receive three normals:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0],[0,1,0],[-1,0,1],[-1,-1,0]],INPUT_CONES=>[[0,1],[1,2],[3]]);
# > print $f->LINEAR_SPAN_NORMALS;
# | 0 0 1
# | 1 0 1
# | -1 1 0

property LINEAR_SPAN_NORMALS : Matrix<Scalar>;

# @category Geometry
# Tells for each maximal cone what is its linear span by naming its normals.
# Indices refer to [[LINEAR_SPAN_NORMALS]].
# Rows correspond to [[MAXIMAL_CONES]].
# An empty row corresponds to a full-dimensional cone.
# @example We construct a fan in 3-space with two 2-dimensional maximal cones and a 1-dimensional maximal cone. This way
# we receive two cones with one normal and one cone with two normals:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0,0],[0,1,0],[-1,0,1],[-1,-1,0]],INPUT_CONES=>[[0,1],[1,2],[3]]);
# > print $f->MAXIMAL_CONES;
# | {0 1}
# | {1 2}
# | {3}
# > print rows_numbered($f->LINEAR_SPAN_NORMALS);
# | 0:0 0 1
# | 1:1 0 1
# | 2:-1 1 0
# > print $f->MAXIMAL_CONES_LINEAR_SPAN_NORMALS;
# | {0}
# | {1}
# | {0 2}

property MAXIMAL_CONES_LINEAR_SPAN_NORMALS : IncidenceMatrix;

rule MAXIMAL_CONES_LINEAR_SPAN_NORMALS : LINEAR_SPAN_NORMALS, ConesPerm.MAXIMAL_CONES_LINEAR_SPAN_NORMALS, ConesPerm.PERMUTATION {
   if ($this->LINEAR_SPAN_NORMALS->rows) {
      $this->MAXIMAL_CONES_LINEAR_SPAN_NORMALS = permuted_rows($this->ConesPerm->MAXIMAL_CONES_LINEAR_SPAN_NORMALS, $this->ConesPerm->PERMUTATION);
   } else {
      # the linear span matrix is empty, nothing to permute
      $this->MAXIMAL_CONES_LINEAR_SPAN_NORMALS = $this->ConesPerm->MAXIMAL_CONES_LINEAR_SPAN_NORMALS;
   }
}
weight 1.10;

# @category Topology
# If the fan is [[SIMPLICIAL]] the simplicial complex obtained by intersecting
# the fan with the unit sphere.
# If the fan is not [[SIMPLICIAL]] the crosscut complex of the intersection.
# @example When intersecting, the [[normal_fan|normal fan]] of the 3-cube gives us a simplicial complex which is a topological 2-sphere:
# > $ic = normal_fan(cube(3))->INTERSECTION_COMPLEX;
# print $ic->SPHERE;
# | true

property INTERSECTION_COMPLEX : topaz::SimplicialComplex;


# @category Topology
# The homology of the intersection of the fan with the unit sphere.
# # @example When intersecting, the [[normal_fan|normal fan]] of the 3-cube gives us a simplicial complex which is a topological 2-sphere:
# > print normal_fan(cube(3))->HOMOLOGY;
# | ({} 0)
# | ({} 0)
# | ({} 1)

property HOMOLOGY : Array<topaz::HomologyGroup<Integer>>;

rule HOMOLOGY = INTERSECTION_COMPLEX.HOMOLOGY;

# @category Combinatorics
# Returns the //i//-th [[MAXIMAL_CONES|maximal cone]].
# @param Int i
# @return Cone
# @example To obtain the cone generated by the x-, y- and z-axis, we can take the first cone of the [[normal_fan|normal fan]] of
# the 3-cube:
# > $c = normal_fan(cube(3))->cone(0);
# > print $c->RAYS;
# | 1 0 0
# | 0 1 0
# | 0 0 1

user_method cone($) : MAXIMAL_CONES {
   my ($self,$i)=@_;
   my $c=new Cone<Scalar>;

   my $a_dim=$c->CONE_AMBIENT_DIM=$self->FAN_AMBIENT_DIM;
   if (defined(my $ls=$self->lookup("LINEALITY_SPACE"))) {
      $c->LINEALITY_SPACE=$ls;
   }
   if (defined(my $ld=$self->lookup("LINEALITY_DIM"))) {
      $c->LINEALITY_DIM=$ld;
   }
   if (defined(my $r=$self->lookup("RAYS")) and defined(my $mc=$self->lookup("MAXIMAL_CONES"))) {
      $c->RAYS=$r->minor($mc->[$i],All);
   }
   if (defined(my $mcf=$self->lookup("MAXIMAL_CONES_FACETS")) and defined(my $fn=$self->lookup("FACET_NORMALS"))) {
      my @facets;
      my $a=0;
      foreach (@{$mcf->row($i)}) {
         if($_!=0) {push(@facets,$_*$fn->row($a)); }
         ++$a;
      }
      $c->FACETS=\@facets;
   }
   if (defined(my $mclsn=$self->lookup("MAXIMAL_CONES_LINEAR_SPAN_NORMALS")) and defined(my $lsn=$self->lookup("LINEAR_SPAN_NORMALS"))) {
      if ($mclsn->rows==0) {
         $c->LINEAR_SPAN=new Matrix<Scalar>(0,$a_dim);
      }
      else {
         $c->LINEAR_SPAN=$lsn->minor($mclsn->[$i],All);
      }
   }
   if (defined(my $mci=$self->lookup("MAXIMAL_CONES_INCIDENCES"))) {
      $c->RAYS_IN_FACETS=$mci->[$i];
   }
   if (defined(my $mccd=$self->lookup("MAXIMAL_CONES_COMBINATORIAL_DIMS"))) {
      $c->COMBINATORIAL_DIM=$mccd->[$i];
   }
   if (defined(my $simp=$self->lookup("SIMPLICIAL"))) {
      if ($simp) {
         $c->SIMPLICIAL=$simp;
      }
   
      if (defined(my $pure=$self->lookup("PURE"))) {
         if ($pure) {
            if (defined(my $fd=$self->lookup("FAN_DIM"))) {
               $c->CONE_DIM=$fd;
            }
            if (defined(my $cd=$self->lookup("COMBINATORIAL_DIM"))) {
               $c->COMBINATORIAL_DIM=$cd;
            }
         }
      }
   }
   return $c;
}

# @category Combinatorics
# Returns an incidence matrix containing the cones of dimension //k//
# @param Int k
# @return IncidenceMatrix
# @example To obtain the 2-dimensional cones in the normal fan of the 3-cube, type
# > $c = normal_fan(cube(3));
# > print $c->cones_of_dim(2);
# | {2 4}
# | {0 4}
# | {0 2}
# | {1 4}
# | {1 2}
# | {3 4}
# | {0 3}
# | {1 3}
# | {2 5}
# | {0 5}
# | {1 5}
# | {3 5}

user_method cones_of_dim($) : HASSE_DIAGRAM {
    my ($self, $k) = @_;
    if ($k < 1) {
        croak("Need k>0");
    }
    my $d = $self->HASSE_DIAGRAM->rank;
    if ($k >= $d) {
        croak("Asking for cones of dimension $k is futile for a cone of combinatorial dimension $d");
    }
    return $self->HASSE_DIAGRAM->cones_of_dim($k);
}
                 
# @category Geometry
# Returns the dimension of the ambient space.
# @return Int
# @example The fan living in the plane containing only the cone which consists of the ray pointing in positive x-direction is
# by definition embedded in the plane:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0]],INPUT_CONES=>[[0]]);
# > print $f->AMBIENT_DIM;
# | 2
user_method AMBIENT_DIM() : FAN_AMBIENT_DIM {
  my ($self)=@_;
  return $self->FAN_AMBIENT_DIM;
}

# @category Geometry
# Returns the dimension of the linear space spanned by the fan.
# @return Int
# @example The fan living in the plane containing only the cone which consists of the ray pointing in positive x-direction is
# 1-dimensional:
# > $f = new PolyhedralFan(INPUT_RAYS=>[[1,0]],INPUT_CONES=>[[0]]);
# > print $f->DIM;
# | 1

user_method DIM {
  my ($self)=@_;
  if (!defined ($self->lookup("LINEALITY_SPACE | INPUT_LINEALITY | INPUT_RAYS | RAYS | FACET_NORMALS | LINEAR_SPAN_NORMALS"))) {
    return $self->COMBINATORIAL_DIM;
 }
  return $self->FAN_DIM;
}

}

object topaz::HyperbolicSurface {
   
   # The secondary fan of the hyperbolic surface.
   # The k-th maximal cone corresponds to the Delaunay triangulation obtained by applying the k-th flip word of [[FLIP_WORDS]].
   # See M. Joswig, R. Löwe, and B. Springborn. Secondary fans and secondary polyhedra of punctured Riemann surfaces. arXiv:1708.08714.
   property SECONDARY_FAN : PolyhedralFan<Rational>;

   rule SECONDARY_FAN, FLIP_WORDS : DCEL, PENNER_COORDINATES {
      secondary_fan_and_flipwords($this);
   }

}


# Local Variables:
# mode: perl
# cperl-indent-level:3
# indent-tabs-mode:nil
# End: