+import ast
import functools
import numbers
+import re
from fractions import Fraction, gcd
This class implements linear expressions.
"""
+ __slots__ = (
+ '_coefficients',
+ '_constant',
+ '_symbols',
+ '_dimension',
+ )
+
def __new__(cls, coefficients=None, constant=0):
if isinstance(coefficients, str):
if constant:
self._coefficients = {}
for symbol, coefficient in coefficients:
if isinstance(symbol, Symbol):
- symbol = str(symbol)
+ symbol = symbol.name
elif not isinstance(symbol, str):
raise TypeError('symbols must be strings or Symbol instances')
if isinstance(coefficient, Constant):
self._dimension = len(self._symbols)
return self
+ @classmethod
+ def _fromast(cls, node):
+ if isinstance(node, ast.Module):
+ assert len(node.body) == 1
+ return cls._fromast(node.body[0])
+ elif isinstance(node, ast.Expr):
+ return cls._fromast(node.value)
+ elif isinstance(node, ast.Name):
+ return Symbol(node.id)
+ elif isinstance(node, ast.Num):
+ return Constant(node.n)
+ elif isinstance(node, ast.UnaryOp):
+ if isinstance(node.op, ast.USub):
+ return -cls._fromast(node.operand)
+ elif isinstance(node, ast.BinOp):
+ left = cls._fromast(node.left)
+ right = cls._fromast(node.right)
+ if isinstance(node.op, ast.Add):
+ return left + right
+ elif isinstance(node.op, ast.Sub):
+ return left - right
+ elif isinstance(node.op, ast.Mult):
+ return left * right
+ elif isinstance(node.op, ast.Div):
+ return left / right
+ raise SyntaxError('invalid syntax')
+
@classmethod
def fromstring(cls, string):
- raise NotImplementedError
+ string = re.sub(r'(\d+|\))\s*([^\W\d_]\w*|\()', r'\1*\2', string)
+ tree = ast.parse(string, 'eval')
+ return cls._fromast(tree)
@property
def symbols(self):
yield self.coefficient(symbol)
yield self.constant
- @property
- def symbol(self):
- raise ValueError('not a symbol: {}'.format(self))
-
def issymbol(self):
return False
class Symbol(Expression):
+ __slots__ = Expression.__slots__ + (
+ '_name',
+ )
+
def __new__(cls, name):
if isinstance(name, Symbol):
- name = name.symbol
+ name = name.name
elif not isinstance(name, str):
raise TypeError('name must be a string or a Symbol instance')
self = object().__new__(cls)
self._coefficients = {name: 1}
self._constant = 0
self._symbols = tuple(name)
- self._symbol = name
+ self._name = name
self._dimension = 1
return self
@property
- def symbol(self):
- return self._symbol
+ def name(self):
+ return self._name
def issymbol(self):
return True
def __repr__(self):
- return '{}({!r})'.format(self.__class__.__name__, self._symbol)
+ return '{}({!r})'.format(self.__class__.__name__, self._name)
def symbols(names):
if isinstance(names, str):
This class implements polyhedrons.
"""
+ __slots__ = (
+ '_equalities',
+ '_inequalities',
+ '_constraints',
+ '_symbols',
+ )
+
def __new__(cls, equalities=None, inequalities=None):
if isinstance(equalities, str):
if inequalities is not None:
@classmethod
def fromstring(cls, string):
- raise NotImplementedError
+ string = string.strip()
+ string = re.sub(r'^\{\s*|\s*\}$', '', string)
+ string = re.sub(r'([^<=>])=([^<=>])', r'\1==\2', string)
+ string = re.sub(r'(\d+|\))\s*([^\W\d_]\w*|\()', r'\1*\2', string)
+ equalities = []
+ inequalities = []
+ for cstr in re.split(r',|;|and|&&|/\\|∧', string, flags=re.I):
+ tree = ast.parse(cstr.strip(), 'eval')
+ if not isinstance(tree, ast.Module) or len(tree.body) != 1:
+ raise SyntaxError('invalid syntax')
+ node = tree.body[0]
+ if not isinstance(node, ast.Expr):
+ raise SyntaxError('invalid syntax')
+ node = node.value
+ if not isinstance(node, ast.Compare):
+ raise SyntaxError('invalid syntax')
+ left = Expression._fromast(node.left)
+ for i in range(len(node.ops)):
+ op = node.ops[i]
+ right = Expression._fromast(node.comparators[i])
+ if isinstance(op, ast.Lt):
+ inequalities.append(right - left - 1)
+ elif isinstance(op, ast.LtE):
+ inequalities.append(right - left)
+ elif isinstance(op, ast.Eq):
+ equalities.append(left - right)
+ elif isinstance(op, ast.GtE):
+ inequalities.append(left - right)
+ elif isinstance(op, ast.Gt):
+ inequalities.append(left - right - 1)
+ else:
+ raise SyntaxError('invalid syntax')
+ left = right
+ return cls(equalities, inequalities)
@property
def equalities(self):
difference = libisl.isl_set_subtract(bset, other)
return difference
-
def __sub__(self, other):
return self.difference(other)
def _toisl(self, symbols=None):
if symbols is None:
symbols = self.symbols
- num_coefficients = len(symbols)
- space = libisl.isl_space_set_alloc(_main_ctx, 0, num_coefficients)
+ dimension = len(symbols)
+ space = libisl.isl_space_set_alloc(_main_ctx, 0, dimension)
bset = libisl.isl_basic_set_universe(libisl.isl_space_copy(space))
ls = libisl.isl_local_space_from_space(space)
- #if there are equalities/inequalities, take each constant and coefficient and add as a constraint to the basic set
- for eq in self.equalities:
+ for equality in self.equalities:
ceq = libisl.isl_equality_alloc(libisl.isl_local_space_copy(ls))
- coeff_eq = dict(eq.coefficients())
- if eq.constant:
- value = str(eq.constant).encode()
- val = libisl.isl_val_read_from_str(_main_ctx, value)
+ for symbol, coefficient in equality.coefficients():
+ val = str(coefficient).encode()
+ val = libisl.isl_val_read_from_str(_main_ctx, val)
+ dim = symbols.index(symbol)
+ ceq = libisl.isl_constraint_set_coefficient_val(ceq, libisl.isl_dim_set, dim, val)
+ if equality.constant != 0:
+ val = str(equality.constant).encode()
+ val = libisl.isl_val_read_from_str(_main_ctx, val)
ceq = libisl.isl_constraint_set_constant_val(ceq, val)
- for eq in coeff_eq:
- number = str(coeff_eq.get(eq)).encode()
- num = libisl.isl_val_read_from_str(_main_ctx, number)
- iden = symbols.index(eq)
- ceq = libisl.isl_constraint_set_coefficient_val(ceq, libisl.isl_dim_set, iden, num) #use 3 for type isl_dim_set
bset = libisl.isl_basic_set_add_constraint(bset, ceq)
- for ineq in self.inequalities:
+ for inequality in self.inequalities:
cin = libisl.isl_inequality_alloc(libisl.isl_local_space_copy(ls))
- coeff_in = dict(ineq.coefficients())
- if ineq.constant:
- value = str(ineq.constant).encode()
- val = libisl.isl_val_read_from_str(_main_ctx, value)
+ for symbol, coefficient in inequality.coefficients():
+ val = str(coefficient).encode()
+ val = libisl.isl_val_read_from_str(_main_ctx, val)
+ dim = symbols.index(symbol)
+ cin = libisl.isl_constraint_set_coefficient_val(cin, libisl.isl_dim_set, dim, val)
+ if inequality.constant != 0:
+ val = str(inequality.constant).encode()
+ val = libisl.isl_val_read_from_str(_main_ctx, val)
cin = libisl.isl_constraint_set_constant_val(cin, val)
- for ineq in coeff_in:
- number = str(coeff_in.get(ineq)).encode()
- num = libisl.isl_val_read_from_str(_main_ctx, number)
- iden = symbols.index(ineq)
- cin = libisl.isl_constraint_set_coefficient_val(cin, libisl.isl_dim_set, iden, num) #use 3 for type isl_dim_set
bset = libisl.isl_basic_set_add_constraint(bset, cin)
bset = isl.BasicSet(bset)
return bset
@classmethod
- def _fromisl(cls, bset):
+ def _fromisl(cls, bset, symbols):
raise NotImplementedError
equalities = ...
inequalities = ...
Universe = Polyhedron()
if __name__ == '__main__':
- ex1 = Expression(coefficients={'a': 6, 'b': 6}, constant= 3) #this is the expression that does not work (even without adding values)
- ex2 = Expression(coefficients={'x': 4, 'y': 2}, constant= 3)
- p = Polyhedron(equalities=[ex2])
- p2 = Polyhedron(equalities=[ex2])
- print(p._toisl()) # checking is values works for toisl
+ p1 = Polyhedron('2a + 2b + 1 == 0') # empty
+ print(p1._toisl())
+ p2 = Polyhedron('3x + 2y + 3 == 0') # not empty
+ print(p2._toisl())
projects / linpy.git / blobdiff