printing out isl form but test gives incorrect values
[linpy.git] / pypol / linear.py
index 5b5d8aa..343acc7 100644 (file)
@@ -1,9 +1,13 @@
-
 import functools
 import numbers
+import ctypes, ctypes.util
+from pypol import isl
 
 from fractions import Fraction, gcd
 
+libisl = ctypes.CDLL(ctypes.util.find_library('isl'))
+
+libisl.isl_printer_get_str.restype = ctypes.c_char_p
 
 __all__ = [
     'Expression',
@@ -14,6 +18,33 @@ __all__ = [
 ]
 
 
+_CONTEXT = isl.Context()
+
+def _polymorphic_method(func):
+    @functools.wraps(func)
+    def wrapper(a, b):
+        if isinstance(b, Expression):
+            return func(a, b)
+        if isinstance(b, numbers.Rational):
+            b = constant(b)
+            return func(a, b)
+        return NotImplemented
+    return wrapper
+
+def _polymorphic_operator(func):
+    # A polymorphic operator should call a polymorphic method, hence we just
+    # have to test the left operand.
+    @functools.wraps(func)
+    def wrapper(a, b):
+        if isinstance(a, numbers.Rational):
+            a = constant(a)
+            return func(a, b)
+        elif isinstance(a, Expression):
+            return func(a, b)
+        raise TypeError('arguments must be linear expressions')
+    return wrapper
+
+
 class Expression:
     """
     This class implements linear expressions.
@@ -43,6 +74,7 @@ class Expression:
         self._constant = constant
         return self
 
+
     def symbols(self):
         yield from sorted(self._coefficients)
 
@@ -78,6 +110,12 @@ class Expression:
             yield self.coefficient(symbol)
         yield self.constant
 
+    def values_int(self):
+        for symbol in self.symbols():
+            return self.coefficient(symbol)
+        return int(self.constant)
+
+
     def symbol(self):
         if not self.issymbol():
             raise ValueError('not a symbol: {}'.format(self))
@@ -96,18 +134,7 @@ class Expression:
     def __neg__(self):
         return self * -1
 
-    def _polymorphic(func):
-        @functools.wraps(func)
-        def wrapper(self, other):
-            if isinstance(other, Expression):
-                return func(self, other)
-            if isinstance(other, numbers.Rational):
-                other = Expression(constant=other)
-                return func(self, other)
-            return NotImplemented
-        return wrapper
-
-    @_polymorphic
+    @_polymorphic_method
     def __add__(self, other):
         coefficients = dict(self.coefficients())
         for symbol, coefficient in other.coefficients():
@@ -120,7 +147,7 @@ class Expression:
 
     __radd__ = __add__
 
-    @_polymorphic
+    @_polymorphic_method
     def __sub__(self, other):
         coefficients = dict(self.coefficients())
         for symbol, coefficient in other.coefficients():
@@ -131,9 +158,10 @@ class Expression:
         constant = self.constant - other.constant
         return Expression(coefficients, constant)
 
-    __rsub__ = __sub__
+    def __rsub__(self, other):
+        return -(self - other)
 
-    @_polymorphic
+    @_polymorphic_method
     def __mul__(self, other):
         if other.isconstant():
             coefficients = dict(self.coefficients())
@@ -148,7 +176,7 @@ class Expression:
 
     __rmul__ = __mul__
 
-    @_polymorphic
+    @_polymorphic_method
     def __truediv__(self, other):
         if other.isconstant():
             coefficients = dict(self.coefficients())
@@ -163,7 +191,7 @@ class Expression:
         return NotImplemented
 
     def __rtruediv__(self, other):
-        if isinstance(other, Rational):
+        if isinstance(other, self):
             if self.isconstant():
                 constant = Fraction(other, self.constant)
                 return Expression(constant=constant)
@@ -206,6 +234,8 @@ class Expression:
         elif constant < 0:
             constant *= -1
             string += ' - {}'.format(constant)
+        if string == '':
+            string = '0'
         return string
 
     def _parenstr(self, always=False):
@@ -228,7 +258,7 @@ class Expression:
     def fromstring(cls, string):
         raise NotImplementedError
 
-    @_polymorphic
+    @_polymorphic_method
     def __eq__(self, other):
         # "normal" equality
         # see http://docs.sympy.org/dev/tutorial/gotchas.html#equals-signs
@@ -244,29 +274,32 @@ class Expression:
                 [value.denominator for value in self.values()])
         return self * lcm
 
-    @_polymorphic
+    @_polymorphic_method
     def _eq(self, other):
         return Polyhedron(equalities=[(self - other)._canonify()])
 
-    @_polymorphic
+    @_polymorphic_method
     def __le__(self, other):
         return Polyhedron(inequalities=[(self - other)._canonify()])
 
-    @_polymorphic
+    @_polymorphic_method
     def __lt__(self, other):
         return Polyhedron(inequalities=[(self - other)._canonify() + 1])
 
-    @_polymorphic
+    @_polymorphic_method
     def __ge__(self, other):
         return Polyhedron(inequalities=[(other - self)._canonify()])
 
-    @_polymorphic
+    @_polymorphic_method
     def __gt__(self, other):
         return Polyhedron(inequalities=[(other - self)._canonify() + 1])
 
 
 def constant(numerator=0, denominator=None):
-    return Expression(constant=Fraction(numerator, denominator))
+    if denominator is None and isinstance(numerator, numbers.Rational):
+        return Expression(constant=3)
+    else:
+        return Expression(constant=Fraction(numerator, denominator))
 
 def symbol(name):
     if not isinstance(name, str):
@@ -279,35 +312,23 @@ def symbols(names):
     return (symbol(name) for name in names)
 
 
-def _operator(func):
-    @functools.wraps(func)
-    def wrapper(a, b):
-        if isinstance(a, numbers.Rational):
-            a = constant(a)
-        if isinstance(b, numbers.Rational):
-            b = constant(b)
-        if isinstance(a, Expression) and isinstance(b, Expression):
-            return func(a, b)
-        raise TypeError('arguments must be linear expressions')
-    return wrapper
-
-@_operator
+@_polymorphic_operator
 def eq(a, b):
     return a._eq(b)
 
-@_operator
+@_polymorphic_operator
 def le(a, b):
     return a <= b
 
-@_operator
+@_polymorphic_operator
 def lt(a, b):
     return a < b
 
-@_operator
+@_polymorphic_operator
 def ge(a, b):
     return a >= b
 
-@_operator
+@_polymorphic_operator
 def gt(a, b):
     return a > b
 
@@ -338,9 +359,11 @@ class Polyhedron:
                     if value.denominator != 1:
                         raise TypeError('non-integer constraint: '
                                 '{} <= 0'.format(constraint))
-                self._inequalities.append(constraint)
-        return self
-
+                self._inequalities.append(constraint)      
+        self._bset = self.to_isl()
+        return self._bset 
+   
+  
     @property
     def equalities(self):
         yield from self._equalities
@@ -348,24 +371,46 @@ class Polyhedron:
     @property
     def inequalities(self):
         yield from self._inequalities
+        
+    @property
+    def constant(self):
+        return self._constant
+
+    def isconstant(self):
+        return len(self._coefficients) == 0
+    
+        
+    def isempty(self):
+        return bool(libisl.isl_basic_set_is_empty(self._bset))
 
     def constraints(self):
         yield from self.equalities
         yield from self.inequalities
 
+
     def symbols(self):
         s = set()
         for constraint in self.constraints():
             s.update(constraint.symbols)
-        yield from sorted(s)
-
+            yield from sorted(s)
+            
+    def symbol_count(self):
+        s = []
+        for constraint in self.constraints():
+            s.append(constraint.symbols)
+        return s     
+        
     @property
     def dimension(self):
         return len(self.symbols())
 
     def __bool__(self):
         # return false if the polyhedron is empty, true otherwise
-        raise NotImplementedError
+        if self._equalities or self._inequalities:
+            return False
+        else:
+            return True
+        
 
     def __contains__(self, value):
         # is the value in the polyhedron?
@@ -374,8 +419,8 @@ class Polyhedron:
     def __eq__(self, other):
         raise NotImplementedError
 
-    def isempty(self):
-        return self == empty
+    def is_empty(self):
+        return
 
     def isuniverse(self):
         return self == universe
@@ -395,6 +440,11 @@ class Polyhedron:
 
     def issuperset(self, other):
         # test whether every element in other is in the polyhedron
+        for value in other:
+            if value == self.constraints():
+                return True 
+            else:
+                return False     
         raise NotImplementedError
 
     def __ge__(self, other):
@@ -451,8 +501,44 @@ class Polyhedron:
     @classmethod
     def fromstring(cls, string):
         raise NotImplementedError
+    
+    def to_isl(self):
+        space = libisl.isl_space_set_alloc(_CONTEXT, 0, len(self.symbol_count()))
+        bset = libisl.isl_basic_set_empty(libisl.isl_space_copy(space))
+        ls = libisl.isl_local_space_from_space(libisl.isl_space_copy(space))
+        ceq = libisl.isl_equality_alloc(libisl.isl_local_space_copy(ls))
+        cin = libisl.isl_inequality_alloc(libisl.isl_local_space_copy(ls))
+        d = Expression().__dict__  #write expression values to dictionary in form {'_constant': value, '_coefficients': value}      
+        '''
+        if there are equalities/inequalities, take each constant and coefficient and add as a constraint to the basic set
+        need to change the symbols method to a lookup table for the integer value for each letter that could be a symbol
+        '''
+        if self._equalities:
+            if '_constant' in d:
+                value = d.get('_constant')
+                ceq = libisl.isl_constraint_set_constant_si(ceq, value)
+            if '_coefficients' in d: 
+                value_co = d.get('_coefficients')
+                if value_co:   #if dictionary not empty add coefficient as to constraint    
+                    ceq = libisl.isl_constraint_set_coefficient_si(ceq, libisl.isl_set_dim, self.symbols(), value_co)  
+            bset = libisl.isl_set_add_constraint(bset, ceq) 
+                       
+        if self._inequalities:     
+            if '_constant' in d:
+                value = d.get('_constant')
+                cin = libisl.isl_constraint_set_constant_si(cin, value)   
+            if '_coefficients' in d: 
+                value_co = d.get('_coefficients')   
+                if value_co: #if dictionary not empty add coefficient as to constraint
+                    cin = libisl.isl_constraint_set_coefficient_si(cin, libisl.isl_set_dim, self.symbols(), value_co)
+            bset = libisl.isl_set_add_constraint(bset, cin) 
+        ip = libisl.isl_printer_to_str(_CONTEXT) #create string printer
+        ip = libisl.isl_printer_print_set(ip, bset) #print set to printer 
+        string = libisl.isl_printer_get_str(ip)   #get string from printer
+        print(string)
+        return bset
+
+empty = eq(1, 1)
 
 
-empty = le(1, 0)
-
 universe = Polyhedron()