CSP-Constraint

Implementation of the CSP constraint class, which is used to represent a constraint in the CSP-Fork library.

Defines types and operations for a CSPConstraint.

Author

Ch. Demko

Date

2024

Typedefs

typedef struct _CSPConstraint CSPConstraint

The constraint of a CSP problem.

typedef bool CSPChecker(const CSPConstraint*, const size_t*, const void*)

The check function of a CSP constraint.

Param constraint:

The constraint to check.

Param values:

The values of the variables.

Param data:

The data to pass to the check function.

Return:

true if the constraint is satisfied, false otherwise.

Pre:

constraint != NULL

Pre:

values != NULL

Functions

CSPConstraint *csp_constraint_create(size_t arity, CSPChecker *check)

Create a constraint with the specified arity and check function.

Parameters:

• arity – The arity of the constraint.

• check – The check function of the constraint.

Returns:

The constraint created or NULL if an error occurred.

Pre:

The csp library is initialised.

Pre:

arity > 0

Pre:

check != NULL

Post:

The constraint variables are initialised to 0.

Post:

The constraint arity is set to the specified arity.

Post:

The constraint check function is set to the specified check function.

void csp_constraint_destroy(CSPConstraint *constraint)

Destroy the constraint.

Parameters:

constraint – The constraint to destroy.

Pre:

The csp library is initialised.

Pre:

constraint != NULL

Post:

The constraint variables are freed.

Post:

The constraint is freed.

size_t csp_constraint_get_arity(const CSPConstraint *constraint)

Get the arity of the constraint.

Parameters:

constraint – The constraint to get the arity.

Returns:

The arity of the constraint.

Pre:

The csp library is initialised.

CSPChecker *csp_constraint_get_check(const CSPConstraint *constraint)

Get the check function of the constraint.

Parameters:

constraint – The constraint to get the check function.

Returns:

The check function of the constraint.

Pre:

The csp library is initialised.

size_t csp_constraint_get_variable(const CSPConstraint *constraint, size_t index)

Get the variable of the constraint at the specified index.

Parameters:

• constraint – The constraint to get the variable.

• index – The index of the variable.

Returns:

The variable at the specified index.

Pre:

The csp library is initialised.

Pre:

index < constraint->arity

void csp_constraint_set_variable(CSPConstraint *constraint, size_t index, size_t variable)

Set the variable of the constraint at the specified index.

Parameters:

• constraint – The constraint to set the variable.

• index – The index of the variable.

• variable – The variable to set.

Pre:

The csp library is initialised.

Pre:

index < constraint->arity