X-Git-Url: https://scm.cri.ensmp.fr/git/linpy.git/blobdiff_plain/56ab422e3bbc5a6a072f5b2a5be9d88d1017f03f..236157f4861732617ec9078a4364464514bd5b4c:/pypol/linear.py

diff --git a/pypol/linear.py b/pypol/linear.py
index 621a157..74b5477 100644
--- a/pypol/linear.py
+++ b/pypol/linear.py
@@ -1,10 +1,12 @@
+import ast
 import functools
 import numbers
+import re
 
 from fractions import Fraction, gcd
 
-from pypol import isl
-from pypol.isl import libisl
+from . import isl
+from .isl import libisl
 
 
 __all__ = [
@@ -48,6 +50,13 @@ class Expression:
     This class implements linear expressions.
     """
 
+    __slots__ = (
+        '_coefficients',
+        '_constant',
+        '_symbols',
+        '_dimension',
+    )
+
     def __new__(cls, coefficients=None, constant=0):
         if isinstance(coefficients, str):
             if constant:
@@ -86,9 +95,36 @@ class Expression:
         self._dimension = len(self._symbols)
         return self
 
+    @classmethod
+    def _fromast(cls, node):
+        if isinstance(node, ast.Module) and 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) and 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):
@@ -293,6 +329,31 @@ class Expression:
     def __gt__(self, other):
         return Polyhedron(inequalities=[(self - other)._toint() - 1])
 
+    @classmethod
+    def fromsympy(cls, expr):
+        import sympy
+        coefficients = {}
+        constant = 0
+        for symbol, coefficient in expr.as_coefficients_dict().items():
+            coefficient = Fraction(coefficient.p, coefficient.q)
+            if symbol == sympy.S.One:
+                constant = coefficient
+            elif isinstance(symbol, sympy.Symbol):
+                symbol = symbol.name
+                coefficients[symbol] = coefficient
+            else:
+                raise ValueError('non-linear expression: {!r}'.format(expr))
+        return cls(coefficients, constant)
+
+    def tosympy(self):
+        import sympy
+        expr = 0
+        for symbol, coefficient in self.coefficients():
+            term = coefficient * sympy.Symbol(symbol)
+            expr += term
+        expr += self.constant
+        return expr
+
 
 class Constant(Expression):
 
@@ -319,11 +380,29 @@ class Constant(Expression):
         return bool(self.constant)
 
     def __repr__(self):
-        return '{}({!r})'.format(self.__class__.__name__, self._constant)
+        if self.constant.denominator == 1:
+            return '{}({!r})'.format(self.__class__.__name__, self.constant)
+        else:
+            return '{}({!r}, {!r})'.format(self.__class__.__name__,
+                self.constant.numerator, self.constant.denominator)
+
+    @classmethod
+    def fromsympy(cls, expr):
+        import sympy
+        if isinstance(expr, sympy.Rational):
+            return cls(expr.p, expr.q)
+        elif isinstance(expr, numbers.Rational):
+            return cls(expr)
+        else:
+            raise TypeError('expr must be a sympy.Rational instance')
 
 
 class Symbol(Expression):
 
+    __slots__ = Expression.__slots__ + (
+        '_name',
+    )
+
     def __new__(cls, name):
         if isinstance(name, Symbol):
             name = name.name
@@ -347,6 +426,15 @@ class Symbol(Expression):
     def __repr__(self):
         return '{}({!r})'.format(self.__class__.__name__, self._name)
 
+    @classmethod
+    def fromsympy(cls, expr):
+        import sympy
+        if isinstance(expr, sympy.Symbol):
+            return cls(expr.name)
+        else:
+            raise TypeError('expr must be a sympy.Symbol instance')
+
+
 def symbols(names):
     if isinstance(names, str):
         names = names.replace(',', ' ').split()
@@ -379,6 +467,13 @@ class Polyhedron:
     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:
@@ -410,9 +505,54 @@ class Polyhedron:
         self._symbols = tuple(sorted(self._symbols))
         return self
 
+    @classmethod
+    def _fromast(cls, node):
+        if isinstance(node, ast.Module) and len(node.body) == 1:
+            return cls._fromast(node.body[0])
+        elif isinstance(node, ast.Expr):
+            return cls._fromast(node.value)
+        elif isinstance(node, ast.BinOp) and isinstance(node.op, ast.BitAnd):
+            equalities1, inequalities1 = cls._fromast(node.left)
+            equalities2, inequalities2 = cls._fromast(node.right)
+            equalities = equalities1 + equalities2
+            inequalities = inequalities1 + inequalities2
+            return equalities, inequalities
+        elif isinstance(node, ast.Compare):
+            equalities = []
+            inequalities = []
+            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:
+                    break
+                left = right
+            else:
+                return equalities, inequalities
+        raise SyntaxError('invalid syntax')
+
     @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)
+        tokens = re.split(r',|;|and|&&|/\\|∧', string, flags=re.I)
+        tokens = ['({})'.format(token) for token in tokens]
+        string = ' & '.join(tokens)
+        tree = ast.parse(string, 'eval')
+        equalities, inequalities = cls._fromast(tree)
+        return cls(equalities, inequalities)
 
     @property
     def equalities(self):
@@ -524,7 +664,6 @@ class Polyhedron:
         difference = libisl.isl_set_subtract(bset, other)
         return difference
 
-
     def __sub__(self, other):
         return self.difference(other)
 
@@ -547,6 +686,48 @@ class Polyhedron:
             return '{}(equalities={!r}, inequalities={!r})' \
                     ''.format(self.__class__.__name__, equalities, inequalities)
 
+    @classmethod
+    def _fromsympy(cls, expr):
+        import sympy
+        equalities = []
+        inequalities = []
+        if expr.func == sympy.And:
+            for arg in expr.args:
+                arg_eqs, arg_ins = cls._fromsympy(arg)
+                equalities.extend(arg_eqs)
+                inequalities.extend(arg_ins)
+        elif expr.func == sympy.Eq:
+            expr = Expression.fromsympy(expr.args[0] - expr.args[1])
+            equalities.append(expr)
+        else:
+            if expr.func == sympy.Lt:
+                expr = Expression.fromsympy(expr.args[1] - expr.args[0] - 1)
+            elif expr.func == sympy.Le:
+                expr = Expression.fromsympy(expr.args[1] - expr.args[0])
+            elif expr.func == sympy.Ge:
+                expr = Expression.fromsympy(expr.args[0] - expr.args[1])
+            elif expr.func == sympy.Gt:
+                expr = Expression.fromsympy(expr.args[0] - expr.args[1] - 1)
+            else:
+                raise ValueError('non-polyhedral expression: {!r}'.format(expr))
+            inequalities.append(expr)
+        return equalities, inequalities
+
+    @classmethod
+    def fromsympy(cls, expr):
+        import sympy
+        equalities, inequalities = cls._fromsympy(expr)
+        return cls(equalities, inequalities)
+
+    def tosympy(self):
+        import sympy
+        constraints = []
+        for equality in self.equalities:
+            constraints.append(sympy.Eq(equality.tosympy(), 0))
+        for inequality in self.inequalities:
+            constraints.append(sympy.Ge(inequality.tosympy(), 0))
+        return sympy.And(*constraints)
+
     def _symbolunion(self, *others):
         symbols = set(self.symbols)
         for other in others:
@@ -556,42 +737,39 @@ class Polyhedron:
     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 = ...
@@ -603,11 +781,13 @@ class Polyhedron:
             { [i0, i1] : 2i1 >= -2 - i0 } '''
 
 Empty = eq(0,1)
+
 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
+    #p = Polyhedron('2a + 2b + 1 == 0') # empty
+    p = Polyhedron('3x + 2y + 3 == 0, y == 0') # not empty
+    ip = p._toisl()
+    print(ip)
+    print(ip.constraints())