Picat Constraint Programming with CP 2

Question 1

In Picat's CP module, which predicate is used to declare a list of decision variables with a shared domain?

Accepted Answer

Vars :: [Low..High]

Answer

The `::` operator with a list on the left and a domain expression on the right constrains all variables in the list to that domain.

Question 2

What does the `indomain` predicate do when called on a CP variable during search in Picat?

Accepted Answer

It assigns the variable each value in its domain on backtracking

Answer

`indomain(Var)` non-deterministically instantiates Var to successive values in its domain, supporting backtracking search.

Question 3

Which global constraint in Picat's CP module enforces that no two variables take the same value?

Accepted Answer

all_different/1

Answer

`all_different(List)` posts a constraint ensuring every pair of variables in the list has distinct values.

Question 4

In Picat CP, what is the correct way to post a constraint that X is strictly less than Y?

Accepted Answer

X #< Y

Answer

Arithmetic constraints on CP variables use the `#` prefix operators such as `#<`, `#>`, `#=`, and `#\=`.

Question 5

What does `solve(Vars)` do in Picat's CP module?

Accepted Answer

Labels all variables in Vars with default search options

Answer

`solve(Vars)` triggers constraint propagation and labeling for the given variable list using default strategies.

Picat Practice Test