Public Member Functions | |
| Congruence (const Congruence &cg) | |
| Ordinary copy-constructor. | |
| Congruence (const Constraint &c) | |
Copy-constructs (modulo 0) from equality constraint c. | |
| ~Congruence () | |
| Destructor. | |
| Congruence & | operator= (const Congruence &cg) |
| Assignment operator. | |
| dimension_type | space_dimension () const |
Returns the dimension of the vector space enclosing *this. | |
| Coefficient_traits::const_reference | coefficient (Variable v) const |
Returns the coefficient of v in *this. | |
| Coefficient_traits::const_reference | inhomogeneous_term () const |
Returns the inhomogeneous term of *this. | |
| Coefficient_traits::const_reference | modulus () const |
Returns a const reference to the modulus of *this. | |
| Congruence & | operator/= (const Coefficient_traits::const_reference k) |
Multiplies k into the modulus of *this. | |
| bool | is_trivial_true () const |
Returns true if and only if *this is a trivially true congruence. | |
| bool | is_trivial_false () const |
Returns true if and only if *this is a trivially false congruence. | |
| bool | is_proper_congruence () const |
Returns true if the modulus is greater than zero. | |
| bool | is_equality () const |
Returns true if *this is an equality. | |
| bool | is_equal_at_dimension (dimension_type dim, const Congruence &cg) const |
Returns true if *this is equal to cg in dimension dim. | |
| memory_size_type | total_memory_in_bytes () const |
Returns a lower bound to the total size in bytes of the memory occupied by *this. | |
| memory_size_type | external_memory_in_bytes () const |
Returns the size in bytes of the memory managed by *this. | |
| bool | OK () const |
| Checks if all the invariants are satisfied. | |
Static Public Member Functions | |
| static dimension_type | max_space_dimension () |
| Returns the maximum space dimension a Congruence can handle. | |
| static const Congruence & | zero_dim_integrality () |
Returns a reference to the true (zero-dimension space) congruence , also known as the integrality congruence. | |
| static const Congruence & | zero_dim_false () |
Returns a reference to the false (zero-dimension space) congruence . | |
Protected Member Functions | |
| void | sign_normalize () |
| Normalizes the signs. | |
| void | normalize () |
| Normalizes signs and the inhomogeneous term. | |
| void | strong_normalize () |
| Calls normalize, then divides out common factors. | |
Friends | |
| void | swap (PPL::Congruence &x, PPL::Congruence &y) |
Specializes std::swap. | |
Related Functions | |
| (Note that these are not member functions.) | |
| std::ostream & | operator<< (std::ostream &s, const Congruence &c) |
| Output operators. | |
| bool | operator== (const Congruence &x, const Congruence &y) |
Returns true if and only if x and y are equivalent. | |
| bool | operator!= (const Congruence &x, const Congruence &y) |
Returns false if and only if x and y are equivalent. | |
| Congruence | operator/ (const Congruence &cg, const Coefficient_traits::const_reference k) |
Returns a copy of cg, multiplying k into the copy's modulus. | |
| Congruence | operator/ (const Constraint &c, const Coefficient_traits::const_reference m) |
Creates a congruence from c, with m as the modulus. | |
An object of the class Congruence is a congruence:

where
is the dimension of the space,
is the integer coefficient of variable
,
is the integer inhomogeneous term and
is the integer modulus; if
, then
represents the equality congruence
and, if
, then the congruence
is said to be a proper congruence.
are typically built by applying the congruence symbol `%=' to a pair of linear expressions. Congruences with modulus m are typically constructed by building a congruence
using the given pair of linear expressions and then adding the modulus m using the modulus symbol is `/'.
x, y and z are defined as follows: Variable x(0); Variable y(1); Variable z(2);
, having space dimension
: Congruence eq_cg((3*x + 5*y - z %= 0) / 0);
, having space dimension
: Congruence mod1_cg(4*x %= 2*y - 13);
, having space dimension
: Congruence mod2_cg((4*x %= 2*y - 13) / 2);
can be specified as follows: Congruence false_cg = Congruence::zero_dim_false();
Congruence false_cg1((Linear_Expression::zero() %= 1) / 0); Congruence false_cg2((Linear_Expression::zero() %= 1) / 2);
: Congruence false_cg3((0*z %= 1) / 0);
e and modulus m (in this case
), we construct a new congruence with the same modulus m but where the linear expression is
(
). Congruence cg1((x - 5*y + 3*z %= 4) / 5); cout << "Congruence cg1: " << cg1 << endl; Coefficient m = cg1.modulus(); if (m == 0) cout << "Congruence cg1 is an equality." << endl; else { Linear_Expression e; for (int i = cg1.space_dimension() - 1; i >= 0; --i) e += 2 * cg1.coefficient(Variable(i)) * Variable(i); e += 2 * cg1.inhomogeneous_term(); Congruence cg2((e %= 0) / m); cout << "Congruence cg2: " << cg2 << endl; }
Congruence cg1: A - 5*B + 3*C %= 4 / 5 Congruence cg2: 2*A - 10*B + 6*C %= 8 / 5
| Parma_Polyhedra_Library::Congruence::Congruence | ( | const Constraint & | c | ) | [explicit] |
Copy-constructs (modulo 0) from equality constraint c.
| std::invalid_argument | Thrown if c is a relation. |
| Coefficient_traits::const_reference Parma_Polyhedra_Library::Congruence::coefficient | ( | Variable | v | ) | const [inline] |
Returns the coefficient of v in *this.
| std::invalid_argument | thrown if the index of v is greater than or equal to the space dimension of *this. |
| Congruence & Parma_Polyhedra_Library::Congruence::operator/= | ( | const Coefficient_traits::const_reference | k | ) | [inline] |
Multiplies k into the modulus of *this.
If called with *this representing the congruence
, then it returns with *this representing the congruence
.
| bool Parma_Polyhedra_Library::Congruence::is_trivial_true | ( | ) | const |
Returns true if and only if *this is a trivially true congruence.
Trivially true congruences are of one the following two forms:
; or
, where n is the space dimension and m is the modulus. | bool Parma_Polyhedra_Library::Congruence::is_trivial_false | ( | ) | const |
Returns true if and only if *this is a trivially false congruence.
Trivially false congruences have one of the following two forms:
where
; or
, where
. | bool Parma_Polyhedra_Library::Congruence::is_proper_congruence | ( | ) | const [inline] |
Returns true if the modulus is greater than zero.
A congruence with a modulus of 0 is a linear equality.
| bool Parma_Polyhedra_Library::Congruence::is_equality | ( | ) | const [inline] |
Returns true if *this is an equality.
A modulus of zero denotes a linear equality.
| void Parma_Polyhedra_Library::Congruence::sign_normalize | ( | ) | [protected] |
Normalizes the signs.
The signs of the coefficients and the inhomogeneous term are normalized, leaving the first non-zero homogeneous coefficient positive.
| void Parma_Polyhedra_Library::Congruence::normalize | ( | ) | [protected] |
Normalizes signs and the inhomogeneous term.
Applies sign_normalize, then reduces the inhomogeneous term to the smallest possible positive number.
| void Parma_Polyhedra_Library::Congruence::strong_normalize | ( | ) | [protected] |
Calls normalize, then divides out common factors.
Strongly normalized Congruences have equivalent semantics if and only if their syntaxes (as output by operator<<) are equal.
| Congruence operator/ | ( | const Congruence & | cg, | |
| const Coefficient_traits::const_reference | k | |||
| ) | [related] |
Returns a copy of cg, multiplying k into the copy's modulus.
If cg represents the congruence
, then the result represents the congruence
.
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