Merge pull request #22005 from praneethratna/21999_polysys

solvers - fixes issue #21999 and solve_poly_system returns correct output for some equations.
sympy · Sep 2, 2021 · 3b03b95 · 3b03b95
2 parents 2c83657 + 33f2d66
commit 3b03b95
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diff --git a/sympy/solvers/polysys.py b/sympy/solvers/polysys.py
@@ -240,6 +240,12 @@ def _solve_reduced_system(system, gens, entry=False):
 
         univariate = list(filter(_is_univariate, basis))
 
+        if len(basis) < len(gens):
+            raise NotImplementedError(filldedent('''
+                only zero-dimensional systems supported
+                (finite number of solutions)
+                '''))
+
         if len(univariate) == 1:
             f = univariate.pop()
         else:

diff --git a/sympy/solvers/tests/test_polysys.py b/sympy/solvers/tests/test_polysys.py
@@ -49,6 +49,11 @@ def test_solve_poly_system():
         [z, -2*x*y**2 + x + y**2*z, y**2*(-z - 4) + 2]))
     raises(PolynomialError, lambda: solve_poly_system([1/x], x))
 
+    raises(NotImplementedError, lambda: solve_poly_system(
+          [x-1,], (x, y)))
+    raises(NotImplementedError, lambda: solve_poly_system(
+          [y-1,], (x, y)))
+
 
 def test_solve_biquadratic():
     x0, y0, x1, y1, r = symbols('x0 y0 x1 y1 r')