transcendental equation solver for solveset: transolve

sympy/solvers/solveset.py

@@ -987,14 +987,25 @@ def _solveset(f, symbol, domain, _check=False):
 
 def term_factors(f):
     """
-    Returns a list of the factors of all terms present in the
-    expression.
+    An iterator that returns the factors of all terms
+    present in the expression.
+
+    Examples
+    ========
+
+    >>> from sympy import symbols
+    >>> from sympy.solvers.solveset import term_factors
+    >>> x = symbols('x')
+    >>> term_factors_obj = term_factors(x**2 - 1)
+    >>> for term in term_factors_obj:
+    ...     print(term)
+    -1
+    x**2
     """
     args = []
     for add_arg in Add.make_args(f):
         for mul_arg in Mul.make_args(add_arg):
-            args.append(mul_arg)
-    return args
+            yield mul_arg
 
 
 def _solve_expo(f, symbol):

sympy/solvers/tests/test_solveset.py

@@ -1733,10 +1733,10 @@ def test_issue_14454():
 
 
 def test_term_factors():
-    assert term_factors(3**x - 2) == [-2, 3**x]
+    assert list(term_factors(3**x - 2)) == [-2, 3**x]
     expr = 4**(x + 1) + 4**(x + 2) + 4**(x - 1) - 3**(x + 2) - 3**(x + 3)
-    assert term_factors(expr) == \
-        [4**(x + 1), 4**(x - 1), 4**(x + 2), -1, 3**(x + 2), -1, 3**(x + 3)]
+    assert set(term_factors(expr)) == set([
+        3**(x + 2), 4**(x + 2), 3**(x + 3), 4**(x - 1), -1, 4**(x + 1)])
 
 
 #################### tests for transolve and its helpers ###############