5.142. element_matrix
DESCRIPTION | LINKS | GRAPH | AUTOMATON |
- Origin
CHIP
- Constraint
- Synonyms
, .
- Arguments
- Restrictions
- Purpose
The collection corresponds to the two-dimensional matrix . is equal to the entry of the previous matrix.
- Example
-
The constraint holds since its last argument is equal to the attribute of the item of the collection such that and .
- Typical
- Symmetry
All occurrences of two distinct values in or can be swapped; all occurrences of a value in or can be renamed to any unused value.
- Reformulation
The constraint can be expressed in term of , where corresponds to the -th line of the matrix and of one constraint.
If we consider the Example slot we get the following constraints:
- Systems
- See also
common keyword: , Β (array constraint).
- Keywords
characteristic of a constraint: automaton, automaton without counters, reified automaton constraint, derived collection.
constraint arguments: ternary constraint.
constraint network structure: centered cyclic(3) constraint network(1).
- Derived Collection
- Arc input(s)
- Arc generator
-
- Arc arity
- Arc constraint(s)
-
- Graph property(ies)
-
- Graph model
Similar to the constraint except that the arc constraint is updated according to the fact that we have a two-dimensional matrix.
PartsΒ (A) andΒ (B) of FigureΒ 5.142.1 respectively show the initial and final graph associated with the Example slot. Since we use the graph property, the unique arc of the final graph is stressed in bold.
Figure 5.142.1. Initial and final graph of the constraint
(a) (b) - Signature
Because of the first condition of the arc constraint the final graph cannot have more than one arc. Therefore we can rewrite to and simplify to .
- Automaton
FigureΒ 5.142.2 depicts the automaton associated with the constraint. Let , and respectively be the , the and the attributes of the collection. To each sextuple corresponds a 0-1 signature variable as well as the following signature constraint: .
Figure 5.142.2. Automaton of the constraint
Figure 5.142.3. Hypergraph of the reformulation corresponding to the automaton of the constraint where and respectively stands for and