Merge branch 'misc' into fix-18492

diofant/core/expr.py

@@ -437,6 +437,8 @@ def is_constant(self, *wrt, **flags):
         True
 
         """
+        from ..functions import Piecewise
+
         simplify = flags.get('simplify', True)
 
         # Except for expressions that contain units, only one of these should
@@ -512,15 +514,16 @@ def is_constant(self, *wrt, **flags):
             deriv = expr.diff(w)
             if simplify:
                 deriv = deriv.simplify()
-            if deriv != 0:
+            if deriv:
                 if not (deriv.is_Number or pure_complex(deriv)):
                     if flags.get('failing_number', False):
                         return failing_number
                     else:
                         assert deriv.free_symbols
                         return  # dead line provided _random returns None in such cases
                 return False
-        return True
+        if not expr.has(Piecewise):
+            return True
 
     def equals(self, other, failing_expression=False):
         """Return True if self == other, False if it doesn't, or None. If

diofant/core/function.py

@@ -29,7 +29,6 @@
 
 import collections
 import inspect
-import typing
 
 import mpmath
 import mpmath.libmp as mlib
@@ -714,8 +713,6 @@ class WildFunction(Function, AtomicExpr):
 
     """
 
-    include: set[typing.Any] = set()
-
     def __init__(self, name, **assumptions):
         from ..sets.sets import FiniteSet, Set
         self.name = name

diofant/functions/elementary/piecewise.py

@@ -285,7 +285,7 @@ def _sort_expr_cond(self, sym, a, b, targetcond=None):
         independent_expr_cond = []
         if isinstance(targetcond, Relational) and targetcond.has(sym):
             targetcond = solve_univariate_inequality(targetcond, sym)
-        for expr, cond in self.args:
+        for expr, cond in self.args:  # pragma: no branch
             if isinstance(cond, Relational) and cond.has(sym):
                 cond = solve_univariate_inequality(cond, sym)
             if isinstance(cond, Or):
@@ -295,7 +295,7 @@ def _sort_expr_cond(self, sym, a, b, targetcond=None):
                 expr_cond.append((expr, cond))
             if cond == true:
                 break
-        for expr, cond in expr_cond:
+        for expr, cond in expr_cond:  # pragma: no branch
             if cond == true:
                 independent_expr_cond.append((expr, cond))
                 default = self.func(*independent_expr_cond)
@@ -407,10 +407,6 @@ def _sort_expr_cond(self, sym, a, b, targetcond=None):
             int_expr.extend(holes)
             if targetcond == true:
                 return [(h[0], h[1], None) for h in holes]
-        elif holes and default is None:
-            raise ValueError('Called interval evaluation over piecewise '  # noqa: SFS101
-                             'function on undefined intervals %s' %
-                             ', '.join([str((h[0], h[1])) for h in holes]))
 
         return int_expr
 
@@ -425,16 +421,14 @@ def _eval_power(self, other):
     def _eval_subs(self, old, new):
         """Piecewise conditions may contain bool which are not of Basic type."""
         args = list(self.args)
-        for i, (e, c) in enumerate(args):
+        for i, (e, c) in enumerate(args):  # pragma: no branch
             c = c._subs(old, new)
             if c != false:
                 e = e._subs(old, new)
             args[i] = e, c
             if c == true:
                 return self.func(*args)
 
-        return self.func(*args)
-
     def _eval_transpose(self):
         return self.func(*[(e.transpose(), c) for e, c in self.args])
 

diofant/printing/ccode.py

@@ -181,14 +181,6 @@ def _print_NegativeInfinity(self, expr):
         return '-HUGE_VAL'
 
     def _print_Piecewise(self, expr):
-        if expr.args[-1].cond != true:
-            # We need the last conditional to be a True, otherwise the resulting
-            # function may not return a result.
-            raise ValueError('All Piecewise expressions must contain an '
-                             '(expr, True) statement to be used as a default '
-                             'condition. Without one, the generated '
-                             'expression may not evaluate to anything under '
-                             'some condition.')
         lines = []
         if expr.has(Assignment):
             for i, (e, c) in enumerate(expr.args):

diofant/printing/fcode.py

@@ -130,14 +130,6 @@ def _get_loop_opening_ending(self, indices):
         return open_lines, close_lines
 
     def _print_Piecewise(self, expr):
-        if expr.args[-1].cond != true:
-            # We need the last conditional to be a True, otherwise the resulting
-            # function may not return a result.
-            raise ValueError('All Piecewise expressions must contain an '
-                             '(expr, True) statement to be used as a default '
-                             'condition. Without one, the generated '
-                             'expression may not evaluate to anything under '
-                             'some condition.')
         lines = []
         if expr.has(Assignment):
             for i, (e, c) in enumerate(expr.args):

diofant/printing/latex.py

@@ -16,7 +16,6 @@
 from ..core.function import _coeff_isneg
 from ..core.operations import AssocOp
 from ..core.relational import Relational
-from ..logic import true
 from ..utilities import default_sort_key, has_variety
 from .conventions import requires_partial, split_super_sub
 from .precedence import PRECEDENCE, precedence
@@ -1236,13 +1235,7 @@ def _print_Relational(self, expr):
     def _print_Piecewise(self, expr):
         ecpairs = [r'%s & \text{for}\: %s' % (self._print(e), self._print(c))
                    for e, c in expr.args[:-1]]
-        if expr.args[-1].cond == true:
-            ecpairs.append(r'%s & \text{otherwise}' %
-                           self._print(expr.args[-1].expr))
-        else:
-            ecpairs.append(r'%s & \text{for}\: %s' %
-                           (self._print(expr.args[-1].expr),
-                            self._print(expr.args[-1].cond)))
+        ecpairs.append(r'%s & \text{otherwise}' % self._print(expr.args[-1].expr))
         tex = r'\begin{cases} %s \end{cases}'
         return tex % r' \\'.join(ecpairs)
 

diofant/printing/octave.py

@@ -379,14 +379,6 @@ def _print_zeta(self, expr):
             return self._print_not_supported(expr)
 
     def _print_Piecewise(self, expr):
-        if expr.args[-1].cond != true:
-            # We need the last conditional to be a True, otherwise the resulting
-            # function may not return a result.
-            raise ValueError('All Piecewise expressions must contain an '
-                             '(expr, True) statement to be used as a default '
-                             'condition. Without one, the generated '
-                             'expression may not evaluate to anything under '
-                             'some condition.')
         lines = []
         if self._settings['inline']:
             # Express each (cond, expr) pair in a nested Horner form:

diofant/tests/core/test_expr.py

@@ -1457,6 +1457,10 @@ def test_is_constant():
 
     assert Integer(2).is_constant() is True
 
+    for _ in range(5):
+        assert Piecewise((x, (x < 0)), (0, True)).is_constant() is not True
+        assert Piecewise((1, (x < 0)), (0, True)).is_constant() is not True
+
 
 def test_equals():
     assert (-3 - sqrt(5) + (-sqrt(10)/2 - sqrt(2)/2)**2).equals(0)