Cleaner and faster linear expressions

[linpy.git] / pypol / domains.py

diff --git a/pypol/domains.py b/pypol/domains.py
index a34b75b..9187081 100644 (file)
--- a/pypol/domains.py
+++ b/pypol/domains.py
@@ -1,8 +1,11 @@
+import ast
 import functools
+import re
 
 from . import islhelper
 
 from .islhelper import mainctx, libisl, isl_set_basic_sets
+from .linexprs import Expression
 
 
 __all__ = [
@@ -47,7 +50,7 @@ class Domain:
         symbols = set()
         for item in iterator:
             symbols.update(item.symbols)
-        return tuple(sorted(symbols))
+        return tuple(sorted(symbols, key=lambda symbol: symbol.name))
 
     @property
     def polyhedra(self):
@@ -135,10 +138,11 @@ class Domain:
         return self.complement()
 
     def simplify(self):
-        # see isl_set_coalesce, isl_set_detect_equalities,
-        # isl_set_remove_redundancies
-        # which ones? in which order?
-        raise NotImplementedError
+        #does not change anything in any of the examples
+        #isl seems to do this naturally
+        islset = self._toislset(self.polyhedra, self.symbols)
+        islset = libisl.isl_set_remove_redundancies(islset)
+        return self._fromislset(islset, self.symbols)
 
     def polyhedral_hull(self):
         # several types of hull are available
@@ -148,10 +152,20 @@ class Domain:
         islbset = libisl.isl_set_polyhedral_hull(islset)
         return Polyhedron._fromislbasicset(islbset, self.symbols)
 
-    def project(self, symbols):
-        # not sure what isl_set_project_out actually does…
-        # use isl_set_drop_constraints_involving_dims instead?
-        raise NotImplementedError
+    def project_out(self, symbols):
+        # use to remove certain variables
+        islset = self._toislset(self.polyhedra, self.symbols)
+        n = 0
+        for index, symbol in reversed(list(enumerate(self.symbols))):
+            if symbol in symbols:
+                n += 1
+            elif n > 0:
+                islset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, index + 1, n)
+                n = 0
+        if n > 0:
+            islset = libisl.isl_set_project_out(islset, libisl.isl_dim_set, 0, n)
+        symbols = [symbol for symbol in self.symbols if symbol not in symbols]
+        return Domain._fromislset(islset, symbols)
 
     def sample(self):
         from .polyhedra import Polyhedron
@@ -242,9 +256,77 @@ class Domain:
             islset1 = libisl.isl_set_union(islset1, islset2)
         return islset1
 
+    @classmethod
+    def _fromast(cls, node):
+        from .polyhedra import Polyhedron
+        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.UnaryOp):
+            domain = cls._fromast(node.operand)
+            if isinstance(node.operand, ast.invert):
+                return Not(domain)
+        elif isinstance(node, ast.BinOp):
+            domain1 = cls._fromast(node.left)
+            domain2 = cls._fromast(node.right)
+            if isinstance(node.op, ast.BitAnd):
+                return And(domain1, domain2)
+            elif isinstance(node.op, ast.BitOr):
+                return Or(domain1, domain2)
+        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 Polyhedron(equalities, inequalities)
+        raise SyntaxError('invalid syntax')
+
+    _RE_BRACES = re.compile(r'^\{\s*|\s*\}$')
+    _RE_EQ = re.compile(r'([^<=>])=([^<=>])')
+    _RE_AND = re.compile(r'\band\b|,|&&|/\\|∧|∩')
+    _RE_OR = re.compile(r'\bor\b|;|\|\||\\/|∨|∪')
+    _RE_NOT = re.compile(r'\bnot\b|!|¬')
+    _RE_NUM_VAR = Expression._RE_NUM_VAR
+    _RE_OPERATORS = re.compile(r'(&|\||~)')
+
     @classmethod
     def fromstring(cls, string):
-        raise NotImplementedError
+        # remove curly brackets
+        string = cls._RE_BRACES.sub(r'', string)
+        # replace '=' by '=='
+        string = cls._RE_EQ.sub(r'\1==\2', string)
+        # replace 'and', 'or', 'not'
+        string = cls._RE_AND.sub(r' & ', string)
+        string = cls._RE_OR.sub(r' | ', string)
+        string = cls._RE_NOT.sub(r' ~', string)
+        # add implicit multiplication operators, e.g. '5x' -> '5*x'
+        string = cls._RE_NUM_VAR.sub(r'\1*\2', string)
+        # add parentheses to force precedence
+        tokens = cls._RE_OPERATORS.split(string)
+        for i, token in enumerate(tokens):
+            if i % 2 == 0:
+                token = '({})'.format(token)
+                tokens[i] = token
+        string = ''.join(tokens)
+        tree = ast.parse(string, 'eval')
+        return cls._fromast(tree)
 
     def __repr__(self):
         assert len(self.polyhedra) >= 2
@@ -258,7 +340,6 @@ class Domain:
     def tosympy(self):
         raise NotImplementedError
 
-
 def And(*domains):
     if len(domains) == 0:
         from .polyhedra import Universe