I am done

rl/Lib/site-packages/sympy/solvers/tests/test_constantsimp.py

@@ -0,0 +1,179 @@
+"""
+If the arbitrary constant class from issue 4435 is ever implemented, this
+should serve as a set of test cases.
+"""
+
+from sympy.core.function import Function
+from sympy.core.numbers import I
+from sympy.core.power import Pow
+from sympy.core.relational import Eq
+from sympy.core.singleton import S
+from sympy.core.symbol import Symbol
+from sympy.functions.elementary.exponential import (exp, log)
+from sympy.functions.elementary.hyperbolic import (cosh, sinh)
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.functions.elementary.trigonometric import (acos, cos, sin)
+from sympy.integrals.integrals import Integral
+from sympy.solvers.ode.ode import constantsimp, constant_renumber
+from sympy.testing.pytest import XFAIL
+
+
+x = Symbol('x')
+y = Symbol('y')
+z = Symbol('z')
+u2 = Symbol('u2')
+_a = Symbol('_a')
+C1 = Symbol('C1')
+C2 = Symbol('C2')
+C3 = Symbol('C3')
+f = Function('f')
+
+
+def test_constant_mul():
+    # We want C1 (Constant) below to absorb the y's, but not the x's
+    assert constant_renumber(constantsimp(y*C1, [C1])) == C1*y
+    assert constant_renumber(constantsimp(C1*y, [C1])) == C1*y
+    assert constant_renumber(constantsimp(x*C1, [C1])) == x*C1
+    assert constant_renumber(constantsimp(C1*x, [C1])) == x*C1
+    assert constant_renumber(constantsimp(2*C1, [C1])) == C1
+    assert constant_renumber(constantsimp(C1*2, [C1])) == C1
+    assert constant_renumber(constantsimp(y*C1*x, [C1, y])) == C1*x
+    assert constant_renumber(constantsimp(x*y*C1, [C1, y])) == x*C1
+    assert constant_renumber(constantsimp(y*x*C1, [C1, y])) == x*C1
+    assert constant_renumber(constantsimp(C1*x*y, [C1, y])) == C1*x
+    assert constant_renumber(constantsimp(x*C1*y, [C1, y])) == x*C1
+    assert constant_renumber(constantsimp(C1*y*(y + 1), [C1])) == C1*y*(y+1)
+    assert constant_renumber(constantsimp(y*C1*(y + 1), [C1])) == C1*y*(y+1)
+    assert constant_renumber(constantsimp(x*(y*C1), [C1])) == x*y*C1
+    assert constant_renumber(constantsimp(x*(C1*y), [C1])) == x*y*C1
+    assert constant_renumber(constantsimp(C1*(x*y), [C1, y])) == C1*x
+    assert constant_renumber(constantsimp((x*y)*C1, [C1, y])) == x*C1
+    assert constant_renumber(constantsimp((y*x)*C1, [C1, y])) == x*C1
+    assert constant_renumber(constantsimp(y*(y + 1)*C1, [C1, y])) == C1
+    assert constant_renumber(constantsimp((C1*x)*y, [C1, y])) == C1*x
+    assert constant_renumber(constantsimp(y*(x*C1), [C1, y])) == x*C1
+    assert constant_renumber(constantsimp((x*C1)*y, [C1, y])) == x*C1
+    assert constant_renumber(constantsimp(C1*x*y*x*y*2, [C1, y])) == C1*x**2
+    assert constant_renumber(constantsimp(C1*x*y*z, [C1, y, z])) == C1*x
+    assert constant_renumber(constantsimp(C1*x*y**2*sin(z), [C1, y, z])) == C1*x
+    assert constant_renumber(constantsimp(C1*C1, [C1])) == C1
+    assert constant_renumber(constantsimp(C1*C2, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C2*C2, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C1*C1*C2, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C1*x*2**x, [C1])) == C1*x*2**x
+
+def test_constant_add():
+    assert constant_renumber(constantsimp(C1 + C1, [C1])) == C1
+    assert constant_renumber(constantsimp(C1 + 2, [C1])) == C1
+    assert constant_renumber(constantsimp(2 + C1, [C1])) == C1
+    assert constant_renumber(constantsimp(C1 + y, [C1, y])) == C1
+    assert constant_renumber(constantsimp(C1 + x, [C1])) == C1 + x
+    assert constant_renumber(constantsimp(C1 + C1, [C1])) == C1
+    assert constant_renumber(constantsimp(C1 + C2, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C2 + C1, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C1 + C2 + C1, [C1, C2])) == C1
+
+
+def test_constant_power_as_base():
+    assert constant_renumber(constantsimp(C1**C1, [C1])) == C1
+    assert constant_renumber(constantsimp(Pow(C1, C1), [C1])) == C1
+    assert constant_renumber(constantsimp(C1**C1, [C1])) == C1
+    assert constant_renumber(constantsimp(C1**C2, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C2**C1, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C2**C2, [C1, C2])) == C1
+    assert constant_renumber(constantsimp(C1**y, [C1, y])) == C1
+    assert constant_renumber(constantsimp(C1**x, [C1])) == C1**x
+    assert constant_renumber(constantsimp(C1**2, [C1])) == C1
+    assert constant_renumber(
+        constantsimp(C1**(x*y), [C1])) == C1**(x*y)
+
+
+def test_constant_power_as_exp():
+    assert constant_renumber(constantsimp(x**C1, [C1])) == x**C1
+    assert constant_renumber(constantsimp(y**C1, [C1, y])) == C1
+    assert constant_renumber(constantsimp(x**y**C1, [C1, y])) == x**C1
+    assert constant_renumber(
+        constantsimp((x**y)**C1, [C1])) == (x**y)**C1
+    assert constant_renumber(
+        constantsimp(x**(y**C1), [C1, y])) == x**C1
+    assert constant_renumber(constantsimp(x**C1**y, [C1, y])) == x**C1
+    assert constant_renumber(
+        constantsimp(x**(C1**y), [C1, y])) == x**C1
+    assert constant_renumber(
+        constantsimp((x**C1)**y, [C1])) == (x**C1)**y
+    assert constant_renumber(constantsimp(2**C1, [C1])) == C1
+    assert constant_renumber(constantsimp(S(2)**C1, [C1])) == C1
+    assert constant_renumber(constantsimp(exp(C1), [C1])) == C1
+    assert constant_renumber(
+        constantsimp(exp(C1 + x), [C1])) == C1*exp(x)
+    assert constant_renumber(constantsimp(Pow(2, C1), [C1])) == C1
+
+
+def test_constant_function():
+    assert constant_renumber(constantsimp(sin(C1), [C1])) == C1
+    assert constant_renumber(constantsimp(f(C1), [C1])) == C1
+    assert constant_renumber(constantsimp(f(C1, C1), [C1])) == C1
+    assert constant_renumber(constantsimp(f(C1, C2), [C1, C2])) == C1
+    assert constant_renumber(constantsimp(f(C2, C1), [C1, C2])) == C1
+    assert constant_renumber(constantsimp(f(C2, C2), [C1, C2])) == C1
+    assert constant_renumber(
+        constantsimp(f(C1, x), [C1])) == f(C1, x)
+    assert constant_renumber(constantsimp(f(C1, y), [C1, y])) == C1
+    assert constant_renumber(constantsimp(f(y, C1), [C1, y])) == C1
+    assert constant_renumber(constantsimp(f(C1, y, C2), [C1, C2, y])) == C1
+
+
+def test_constant_function_multiple():
+    # The rules to not renumber in this case would be too complicated, and
+    # dsolve is not likely to ever encounter anything remotely like this.
+    assert constant_renumber(
+        constantsimp(f(C1, C1, x), [C1])) == f(C1, C1, x)
+
+
+def test_constant_multiple():
+    assert constant_renumber(constantsimp(C1*2 + 2, [C1])) == C1
+    assert constant_renumber(constantsimp(x*2/C1, [C1])) == C1*x
+    assert constant_renumber(constantsimp(C1**2*2 + 2, [C1])) == C1
+    assert constant_renumber(
+        constantsimp(sin(2*C1) + x + sqrt(2), [C1])) == C1 + x
+    assert constant_renumber(constantsimp(2*C1 + C2, [C1, C2])) == C1
+
+def test_constant_repeated():
+    assert C1 + C1*x == constant_renumber( C1 + C1*x)
+
+def test_ode_solutions():
+    # only a few examples here, the rest will be tested in the actual dsolve tests
+    assert constant_renumber(constantsimp(C1*exp(2*x) + exp(x)*(C2 + C3), [C1, C2, C3])) == \
+        constant_renumber(C1*exp(x) + C2*exp(2*x))
+    assert constant_renumber(
+        constantsimp(Eq(f(x), I*C1*sinh(x/3) + C2*cosh(x/3)), [C1, C2])
+        ) == constant_renumber(Eq(f(x), C1*sinh(x/3) + C2*cosh(x/3)))
+    assert constant_renumber(constantsimp(Eq(f(x), acos((-C1)/cos(x))), [C1])) == \
+        Eq(f(x), acos(C1/cos(x)))
+    assert constant_renumber(
+        constantsimp(Eq(log(f(x)/C1) + 2*exp(x/f(x)), 0), [C1])
+        ) == Eq(log(C1*f(x)) + 2*exp(x/f(x)), 0)
+    assert constant_renumber(constantsimp(Eq(log(x*sqrt(2)*sqrt(1/x)*sqrt(f(x))
+        /C1) + x**2/(2*f(x)**2), 0), [C1])) == \
+        Eq(log(C1*sqrt(x)*sqrt(f(x))) + x**2/(2*f(x)**2), 0)
+    assert constant_renumber(constantsimp(Eq(-exp(-f(x)/x)*sin(f(x)/x)/2 + log(x/C1) -
+        cos(f(x)/x)*exp(-f(x)/x)/2, 0), [C1])) == \
+        Eq(-exp(-f(x)/x)*sin(f(x)/x)/2 + log(C1*x) - cos(f(x)/x)*
+           exp(-f(x)/x)/2, 0)
+    assert constant_renumber(constantsimp(Eq(-Integral(-1/(sqrt(1 - u2**2)*u2),
+        (u2, _a, x/f(x))) + log(f(x)/C1), 0), [C1])) == \
+        Eq(-Integral(-1/(u2*sqrt(1 - u2**2)), (u2, _a, x/f(x))) +
+        log(C1*f(x)), 0)
+    assert [constantsimp(i, [C1]) for i in [Eq(f(x), sqrt(-C1*x + x**2)), Eq(f(x), -sqrt(-C1*x + x**2))]] == \
+        [Eq(f(x), sqrt(x*(C1 + x))), Eq(f(x), -sqrt(x*(C1 + x)))]
+
+
+@XFAIL
+def test_nonlocal_simplification():
+    assert constantsimp(C1 + C2+x*C2, [C1, C2]) == C1 + C2*x
+
+
+def test_constant_Eq():
+    # C1 on the rhs is well-tested, but the lhs is only tested here
+    assert constantsimp(Eq(C1, 3 + f(x)*x), [C1]) == Eq(x*f(x), C1)
+    assert constantsimp(Eq(C1, 3 * f(x)*x), [C1]) == Eq(f(x)*x, C1)

rl/Lib/site-packages/sympy/solvers/tests/test_decompogen.py

@@ -0,0 +1,59 @@
+from sympy.solvers.decompogen import decompogen, compogen
+from sympy.core.symbol import symbols
+from sympy.functions.elementary.complexes import Abs
+from sympy.functions.elementary.exponential import exp
+from sympy.functions.elementary.miscellaneous import sqrt, Max
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.testing.pytest import XFAIL, raises
+
+x, y = symbols('x y')
+
+
+def test_decompogen():
+    assert decompogen(sin(cos(x)), x) == [sin(x), cos(x)]
+    assert decompogen(sin(x)**2 + sin(x) + 1, x) == [x**2 + x + 1, sin(x)]
+    assert decompogen(sqrt(6*x**2 - 5), x) == [sqrt(x), 6*x**2 - 5]
+    assert decompogen(sin(sqrt(cos(x**2 + 1))), x) == [sin(x), sqrt(x), cos(x), x**2 + 1]
+    assert decompogen(Abs(cos(x)**2 + 3*cos(x) - 4), x) == [Abs(x), x**2 + 3*x - 4, cos(x)]
+    assert decompogen(sin(x)**2 + sin(x) - sqrt(3)/2, x) == [x**2 + x - sqrt(3)/2, sin(x)]
+    assert decompogen(Abs(cos(y)**2 + 3*cos(x) - 4), x) == [Abs(x), 3*x + cos(y)**2 - 4, cos(x)]
+    assert decompogen(x, y) == [x]
+    assert decompogen(1, x) == [1]
+    assert decompogen(Max(3, x), x) == [Max(3, x)]
+    raises(TypeError, lambda: decompogen(x < 5, x))
+    u = 2*x + 3
+    assert decompogen(Max(sqrt(u),(u)**2), x) == [Max(sqrt(x), x**2), u]
+    assert decompogen(Max(u, u**2, y), x) == [Max(x, x**2, y), u]
+    assert decompogen(Max(sin(x), u), x) == [Max(2*x + 3, sin(x))]
+
+
+def test_decompogen_poly():
+    assert decompogen(x**4 + 2*x**2 + 1, x) == [x**2 + 2*x + 1, x**2]
+    assert decompogen(x**4 + 2*x**3 - x - 1, x) == [x**2 - x - 1, x**2 + x]
+
+
+@XFAIL
+def test_decompogen_fails():
+    A = lambda x: x**2 + 2*x + 3
+    B = lambda x: 4*x**2 + 5*x + 6
+    assert decompogen(A(x*exp(x)), x) == [x**2 + 2*x + 3, x*exp(x)]
+    assert decompogen(A(B(x)), x) == [x**2 + 2*x + 3, 4*x**2 + 5*x + 6]
+    assert decompogen(A(1/x + 1/x**2), x) == [x**2 + 2*x + 3, 1/x + 1/x**2]
+    assert decompogen(A(1/x + 2/(x + 1)), x) == [x**2 + 2*x + 3, 1/x + 2/(x + 1)]
+
+
+def test_compogen():
+    assert compogen([sin(x), cos(x)], x) == sin(cos(x))
+    assert compogen([x**2 + x + 1, sin(x)], x) == sin(x)**2 + sin(x) + 1
+    assert compogen([sqrt(x), 6*x**2 - 5], x) == sqrt(6*x**2 - 5)
+    assert compogen([sin(x), sqrt(x), cos(x), x**2 + 1], x) == sin(sqrt(
+                                                                cos(x**2 + 1)))
+    assert compogen([Abs(x), x**2 + 3*x - 4, cos(x)], x) == Abs(cos(x)**2 +
+                                                                3*cos(x) - 4)
+    assert compogen([x**2 + x - sqrt(3)/2, sin(x)], x) == (sin(x)**2 + sin(x) -
+                                                           sqrt(3)/2)
+    assert compogen([Abs(x), 3*x + cos(y)**2 - 4, cos(x)], x) == \
+        Abs(3*cos(x) + cos(y)**2 - 4)
+    assert compogen([x**2 + 2*x + 1, x**2], x) == x**4 + 2*x**2 + 1
+    # the result is in unsimplified form
+    assert compogen([x**2 - x - 1, x**2 + x], x) == -x**2 - x + (x**2 + x)**2 - 1

rl/Lib/site-packages/sympy/solvers/tests/test_inequalities.py

@@ -0,0 +1,500 @@
+"""Tests for tools for solving inequalities and systems of inequalities. """
+
+from sympy.concrete.summations import Sum
+from sympy.core.function import Function
+from sympy.core.numbers import I, Rational, oo, pi
+from sympy.core.relational import Eq, Ge, Gt, Le, Lt, Ne
+from sympy.core.singleton import S
+from sympy.core.symbol import (Dummy, Symbol)
+from sympy.functions.elementary.complexes import Abs
+from sympy.functions.elementary.exponential import exp, log
+from sympy.functions.elementary.miscellaneous import root, sqrt
+from sympy.functions.elementary.piecewise import Piecewise
+from sympy.functions.elementary.trigonometric import cos, sin, tan
+from sympy.integrals.integrals import Integral
+from sympy.logic.boolalg import And, Or
+from sympy.polys.polytools import Poly, PurePoly
+from sympy.sets.sets import FiniteSet, Interval, Union
+from sympy.solvers.inequalities import (reduce_inequalities,
+                                        solve_poly_inequality as psolve,
+                                        reduce_rational_inequalities,
+                                        solve_univariate_inequality as isolve,
+                                        reduce_abs_inequality,
+                                        _solve_inequality)
+from sympy.polys.rootoftools import rootof
+from sympy.solvers.solvers import solve
+from sympy.solvers.solveset import solveset
+from sympy.core.mod import Mod
+from sympy.abc import x, y
+
+from sympy.testing.pytest import raises, XFAIL
+
+
+inf = oo.evalf()
+
+
+def test_solve_poly_inequality():
+    assert psolve(Poly(0, x), '==') == [S.Reals]
+    assert psolve(Poly(1, x), '==') == [S.EmptySet]
+    assert psolve(PurePoly(x + 1, x), ">") == [Interval(-1, oo, True, False)]
+
+
+def test_reduce_poly_inequalities_real_interval():
+    assert reduce_rational_inequalities(
+        [[Eq(x**2, 0)]], x, relational=False) == FiniteSet(0)
+    assert reduce_rational_inequalities(
+        [[Le(x**2, 0)]], x, relational=False) == FiniteSet(0)
+    assert reduce_rational_inequalities(
+        [[Lt(x**2, 0)]], x, relational=False) == S.EmptySet
+    assert reduce_rational_inequalities(
+        [[Ge(x**2, 0)]], x, relational=False) == \
+        S.Reals if x.is_real else Interval(-oo, oo)
+    assert reduce_rational_inequalities(
+        [[Gt(x**2, 0)]], x, relational=False) == \
+        FiniteSet(0).complement(S.Reals)
+    assert reduce_rational_inequalities(
+        [[Ne(x**2, 0)]], x, relational=False) == \
+        FiniteSet(0).complement(S.Reals)
+
+    assert reduce_rational_inequalities(
+        [[Eq(x**2, 1)]], x, relational=False) == FiniteSet(-1, 1)
+    assert reduce_rational_inequalities(
+        [[Le(x**2, 1)]], x, relational=False) == Interval(-1, 1)
+    assert reduce_rational_inequalities(
+        [[Lt(x**2, 1)]], x, relational=False) == Interval(-1, 1, True, True)
+    assert reduce_rational_inequalities(
+        [[Ge(x**2, 1)]], x, relational=False) == \
+        Union(Interval(-oo, -1), Interval(1, oo))
+    assert reduce_rational_inequalities(
+        [[Gt(x**2, 1)]], x, relational=False) == \
+        Interval(-1, 1).complement(S.Reals)
+    assert reduce_rational_inequalities(
+        [[Ne(x**2, 1)]], x, relational=False) == \
+        FiniteSet(-1, 1).complement(S.Reals)
+    assert reduce_rational_inequalities([[Eq(
+        x**2, 1.0)]], x, relational=False) == FiniteSet(-1.0, 1.0).evalf()
+    assert reduce_rational_inequalities(
+        [[Le(x**2, 1.0)]], x, relational=False) == Interval(-1.0, 1.0)
+    assert reduce_rational_inequalities([[Lt(
+        x**2, 1.0)]], x, relational=False) == Interval(-1.0, 1.0, True, True)
+    assert reduce_rational_inequalities(
+        [[Ge(x**2, 1.0)]], x, relational=False) == \
+        Union(Interval(-inf, -1.0), Interval(1.0, inf))
+    assert reduce_rational_inequalities(
+        [[Gt(x**2, 1.0)]], x, relational=False) == \
+        Union(Interval(-inf, -1.0, right_open=True),
+        Interval(1.0, inf, left_open=True))
+    assert reduce_rational_inequalities([[Ne(
+        x**2, 1.0)]], x, relational=False) == \
+        FiniteSet(-1.0, 1.0).complement(S.Reals)
+
+    s = sqrt(2)
+
+    assert reduce_rational_inequalities([[Lt(
+        x**2 - 1, 0), Gt(x**2 - 1, 0)]], x, relational=False) == S.EmptySet
+    assert reduce_rational_inequalities([[Le(x**2 - 1, 0), Ge(
+        x**2 - 1, 0)]], x, relational=False) == FiniteSet(-1, 1)
+    assert reduce_rational_inequalities(
+        [[Le(x**2 - 2, 0), Ge(x**2 - 1, 0)]], x, relational=False
+        ) == Union(Interval(-s, -1, False, False), Interval(1, s, False, False))
+    assert reduce_rational_inequalities(
+        [[Le(x**2 - 2, 0), Gt(x**2 - 1, 0)]], x, relational=False
+        ) == Union(Interval(-s, -1, False, True), Interval(1, s, True, False))
+    assert reduce_rational_inequalities(
+        [[Lt(x**2 - 2, 0), Ge(x**2 - 1, 0)]], x, relational=False
+        ) == Union(Interval(-s, -1, True, False), Interval(1, s, False, True))
+    assert reduce_rational_inequalities(
+        [[Lt(x**2 - 2, 0), Gt(x**2 - 1, 0)]], x, relational=False
+        ) == Union(Interval(-s, -1, True, True), Interval(1, s, True, True))
+    assert reduce_rational_inequalities(
+        [[Lt(x**2 - 2, 0), Ne(x**2 - 1, 0)]], x, relational=False
+        ) == Union(Interval(-s, -1, True, True), Interval(-1, 1, True, True),
+        Interval(1, s, True, True))
+
+    assert reduce_rational_inequalities([[Lt(x**2, -1.)]], x) is S.false
+
+
+def test_reduce_poly_inequalities_complex_relational():
+    assert reduce_rational_inequalities(
+        [[Eq(x**2, 0)]], x, relational=True) == Eq(x, 0)
+    assert reduce_rational_inequalities(
+        [[Le(x**2, 0)]], x, relational=True) == Eq(x, 0)
+    assert reduce_rational_inequalities(
+        [[Lt(x**2, 0)]], x, relational=True) == False
+    assert reduce_rational_inequalities(
+        [[Ge(x**2, 0)]], x, relational=True) == And(Lt(-oo, x), Lt(x, oo))
+    assert reduce_rational_inequalities(
+        [[Gt(x**2, 0)]], x, relational=True) == \
+        And(Gt(x, -oo), Lt(x, oo), Ne(x, 0))
+    assert reduce_rational_inequalities(
+        [[Ne(x**2, 0)]], x, relational=True) == \
+        And(Gt(x, -oo), Lt(x, oo), Ne(x, 0))
+
+    for one in (S.One, S(1.0)):
+        inf = one*oo
+        assert reduce_rational_inequalities(
+            [[Eq(x**2, one)]], x, relational=True) == \
+            Or(Eq(x, -one), Eq(x, one))
+        assert reduce_rational_inequalities(
+            [[Le(x**2, one)]], x, relational=True) == \
+            And(And(Le(-one, x), Le(x, one)))
+        assert reduce_rational_inequalities(
+            [[Lt(x**2, one)]], x, relational=True) == \
+            And(And(Lt(-one, x), Lt(x, one)))
+        assert reduce_rational_inequalities(
+            [[Ge(x**2, one)]], x, relational=True) == \
+            And(Or(And(Le(one, x), Lt(x, inf)), And(Le(x, -one), Lt(-inf, x))))
+        assert reduce_rational_inequalities(
+            [[Gt(x**2, one)]], x, relational=True) == \
+            And(Or(And(Lt(-inf, x), Lt(x, -one)), And(Lt(one, x), Lt(x, inf))))
+        assert reduce_rational_inequalities(
+            [[Ne(x**2, one)]], x, relational=True) == \
+            Or(And(Lt(-inf, x), Lt(x, -one)),
+               And(Lt(-one, x), Lt(x, one)),
+               And(Lt(one, x), Lt(x, inf)))
+
+
+def test_reduce_rational_inequalities_real_relational():
+    assert reduce_rational_inequalities([], x) == False
+    assert reduce_rational_inequalities(
+        [[(x**2 + 3*x + 2)/(x**2 - 16) >= 0]], x, relational=False) == \
+        Union(Interval.open(-oo, -4), Interval(-2, -1), Interval.open(4, oo))
+
+    assert reduce_rational_inequalities(
+        [[((-2*x - 10)*(3 - x))/((x**2 + 5)*(x - 2)**2) < 0]], x,
+        relational=False) == \
+        Union(Interval.open(-5, 2), Interval.open(2, 3))
+
+    assert reduce_rational_inequalities([[(x + 1)/(x - 5) <= 0]], x,
+        relational=False) == \
+        Interval.Ropen(-1, 5)
+
+    assert reduce_rational_inequalities([[(x**2 + 4*x + 3)/(x - 1) > 0]], x,
+        relational=False) == \
+        Union(Interval.open(-3, -1), Interval.open(1, oo))
+
+    assert reduce_rational_inequalities([[(x**2 - 16)/(x - 1)**2 < 0]], x,
+        relational=False) == \
+        Union(Interval.open(-4, 1), Interval.open(1, 4))
+
+    assert reduce_rational_inequalities([[(3*x + 1)/(x + 4) >= 1]], x,
+        relational=False) == \
+        Union(Interval.open(-oo, -4), Interval.Ropen(Rational(3, 2), oo))
+
+    assert reduce_rational_inequalities([[(x - 8)/x <= 3 - x]], x,
+        relational=False) == \
+        Union(Interval.Lopen(-oo, -2), Interval.Lopen(0, 4))
+
+    # issue sympy/sympy#10237
+    assert reduce_rational_inequalities(
+        [[x < oo, x >= 0, -oo < x]], x, relational=False) == Interval(0, oo)
+
+
+def test_reduce_abs_inequalities():
+    e = abs(x - 5) < 3
+    ans = And(Lt(2, x), Lt(x, 8))
+    assert reduce_inequalities(e) == ans
+    assert reduce_inequalities(e, x) == ans
+    assert reduce_inequalities(abs(x - 5)) == Eq(x, 5)
+    assert reduce_inequalities(
+        abs(2*x + 3) >= 8) == Or(And(Le(Rational(5, 2), x), Lt(x, oo)),
+        And(Le(x, Rational(-11, 2)), Lt(-oo, x)))
+    assert reduce_inequalities(abs(x - 4) + abs(
+        3*x - 5) < 7) == And(Lt(S.Half, x), Lt(x, 4))
+    assert reduce_inequalities(abs(x - 4) + abs(3*abs(x) - 5) < 7) == \
+        Or(And(S(-2) < x, x < -1), And(S.Half < x, x < 4))
+
+    nr = Symbol('nr', extended_real=False)
+    raises(TypeError, lambda: reduce_inequalities(abs(nr - 5) < 3))
+    assert reduce_inequalities(x < 3, symbols=[x, nr]) == And(-oo < x, x < 3)
+
+
+def test_reduce_inequalities_general():
+    assert reduce_inequalities(Ge(sqrt(2)*x, 1)) == And(sqrt(2)/2 <= x, x < oo)
+    assert reduce_inequalities(x + 1 > 0) == And(S.NegativeOne < x, x < oo)
+
+
+def test_reduce_inequalities_boolean():
+    assert reduce_inequalities(
+        [Eq(x**2, 0), True]) == Eq(x, 0)
+    assert reduce_inequalities([Eq(x**2, 0), False]) == False
+    assert reduce_inequalities(x**2 >= 0) is S.true  # issue 10196
+
+
+def test_reduce_inequalities_multivariate():
+    assert reduce_inequalities([Ge(x**2, 1), Ge(y**2, 1)]) == And(
+        Or(And(Le(S.One, x), Lt(x, oo)), And(Le(x, -1), Lt(-oo, x))),
+        Or(And(Le(S.One, y), Lt(y, oo)), And(Le(y, -1), Lt(-oo, y))))
+
+
+def test_reduce_inequalities_errors():
+    raises(NotImplementedError, lambda: reduce_inequalities(Ge(sin(x) + x, 1)))
+    raises(NotImplementedError, lambda: reduce_inequalities(Ge(x**2*y + y, 1)))
+
+
+def test__solve_inequalities():
+    assert reduce_inequalities(x + y < 1, symbols=[x]) == (x < 1 - y)
+    assert reduce_inequalities(x + y >= 1, symbols=[x]) == (x < oo) & (x >= -y + 1)
+    assert reduce_inequalities(Eq(0, x - y), symbols=[x]) == Eq(x, y)
+    assert reduce_inequalities(Ne(0, x - y), symbols=[x]) == Ne(x, y)
+
+
+def test_issue_6343():
+    eq = -3*x**2/2 - x*Rational(45, 4) + Rational(33, 2) > 0
+    assert reduce_inequalities(eq) == \
+        And(x < Rational(-15, 4) + sqrt(401)/4, -sqrt(401)/4 - Rational(15, 4) < x)
+
+
+def test_issue_8235():
+    assert reduce_inequalities(x**2 - 1 < 0) == \
+        And(S.NegativeOne < x, x < 1)
+    assert reduce_inequalities(x**2 - 1 <= 0) == \
+        And(S.NegativeOne <= x, x <= 1)
+    assert reduce_inequalities(x**2 - 1 > 0) == \
+        Or(And(-oo < x, x < -1), And(x < oo, S.One < x))
+    assert reduce_inequalities(x**2 - 1 >= 0) == \
+        Or(And(-oo < x, x <= -1), And(S.One <= x, x < oo))
+
+    eq = x**8 + x - 9  # we want CRootOf solns here
+    sol = solve(eq >= 0)
+    tru = Or(And(rootof(eq, 1) <= x, x < oo), And(-oo < x, x <= rootof(eq, 0)))
+    assert sol == tru
+
+    # recast vanilla as real
+    assert solve(sqrt((-x + 1)**2) < 1) == And(S.Zero < x, x < 2)
+
+
+def test_issue_5526():
+    assert reduce_inequalities(0 <=
+        x + Integral(y**2, (y, 1, 3)) - 1, [x]) == \
+        (x >= -Integral(y**2, (y, 1, 3)) + 1)
+    f = Function('f')
+    e = Sum(f(x), (x, 1, 3))
+    assert reduce_inequalities(0 <= x + e + y**2, [x]) == \
+        (x >= -y**2 - Sum(f(x), (x, 1, 3)))
+
+
+def test_solve_univariate_inequality():
+    assert isolve(x**2 >= 4, x, relational=False) == Union(Interval(-oo, -2),
+        Interval(2, oo))
+    assert isolve(x**2 >= 4, x) == Or(And(Le(2, x), Lt(x, oo)), And(Le(x, -2),
+        Lt(-oo, x)))
+    assert isolve((x - 1)*(x - 2)*(x - 3) >= 0, x, relational=False) == \
+        Union(Interval(1, 2), Interval(3, oo))
+    assert isolve((x - 1)*(x - 2)*(x - 3) >= 0, x) == \
+        Or(And(Le(1, x), Le(x, 2)), And(Le(3, x), Lt(x, oo)))
+    assert isolve((x - 1)*(x - 2)*(x - 4) < 0, x, domain = FiniteSet(0, 3)) == \
+        Or(Eq(x, 0), Eq(x, 3))
+    # issue 2785:
+    assert isolve(x**3 - 2*x - 1 > 0, x, relational=False) == \
+        Union(Interval(-1, -sqrt(5)/2 + S.Half, True, True),
+              Interval(S.Half + sqrt(5)/2, oo, True, True))
+    # issue 2794:
+    assert isolve(x**3 - x**2 + x - 1 > 0, x, relational=False) == \
+        Interval(1, oo, True)
+    #issue 13105
+    assert isolve((x + I)*(x + 2*I) < 0, x) == Eq(x, 0)
+    assert isolve(((x - 1)*(x - 2) + I)*((x - 1)*(x - 2) + 2*I) < 0, x) == Or(Eq(x, 1), Eq(x, 2))
+    assert isolve((((x - 1)*(x - 2) + I)*((x - 1)*(x - 2) + 2*I))/(x - 2) > 0, x) == Eq(x, 1)
+    raises (ValueError, lambda: isolve((x**2 - 3*x*I + 2)/x < 0, x))
+
+    # numerical testing in valid() is needed
+    assert isolve(x**7 - x - 2 > 0, x) == \
+        And(rootof(x**7 - x - 2, 0) < x, x < oo)
+
+    # handle numerator and denominator; although these would be handled as
+    # rational inequalities, these test confirm that the right thing is done
+    # when the domain is EX (e.g. when 2 is replaced with sqrt(2))
+    assert isolve(1/(x - 2) > 0, x) == And(S(2) < x, x < oo)
+    den = ((x - 1)*(x - 2)).expand()
+    assert isolve((x - 1)/den <= 0, x) == \
+        (x > -oo) & (x < 2) & Ne(x, 1)
+
+    n = Dummy('n')
+    raises(NotImplementedError, lambda: isolve(Abs(x) <= n, x, relational=False))
+    c1 = Dummy("c1", positive=True)
+    raises(NotImplementedError, lambda: isolve(n/c1 < 0, c1))
+    n = Dummy('n', negative=True)
+    assert isolve(n/c1 > -2, c1) == (-n/2 < c1)
+    assert isolve(n/c1 < 0, c1) == True
+    assert isolve(n/c1 > 0, c1) == False
+
+    zero = cos(1)**2 + sin(1)**2 - 1
+    raises(NotImplementedError, lambda: isolve(x**2 < zero, x))
+    raises(NotImplementedError, lambda: isolve(
+        x**2 < zero*I, x))
+    raises(NotImplementedError, lambda: isolve(1/(x - y) < 2, x))
+    raises(NotImplementedError, lambda: isolve(1/(x - y) < 0, x))
+    raises(TypeError, lambda: isolve(x - I < 0, x))
+
+    zero = x**2 + x - x*(x + 1)
+    assert isolve(zero < 0, x, relational=False) is S.EmptySet
+    assert isolve(zero <= 0, x, relational=False) is S.Reals
+
+    # make sure iter_solutions gets a default value
+    raises(NotImplementedError, lambda: isolve(
+        Eq(cos(x)**2 + sin(x)**2, 1), x))
+
+
+def test_trig_inequalities():
+    # all the inequalities are solved in a periodic interval.
+    assert isolve(sin(x) < S.Half, x, relational=False) == \
+        Union(Interval(0, pi/6, False, True), Interval.open(pi*Rational(5, 6), 2*pi))
+    assert isolve(sin(x) > S.Half, x, relational=False) == \
+        Interval(pi/6, pi*Rational(5, 6), True, True)
+    assert isolve(cos(x) < S.Zero, x, relational=False) == \
+        Interval(pi/2, pi*Rational(3, 2), True, True)
+    assert isolve(cos(x) >= S.Zero, x, relational=False) == \
+        Union(Interval(0, pi/2), Interval.Ropen(pi*Rational(3, 2), 2*pi))
+
+    assert isolve(tan(x) < S.One, x, relational=False) == \
+        Union(Interval.Ropen(0, pi/4), Interval.open(pi/2, pi))
+
+    assert isolve(sin(x) <= S.Zero, x, relational=False) == \
+        Union(FiniteSet(S.Zero), Interval.Ropen(pi, 2*pi))
+
+    assert isolve(sin(x) <= S.One, x, relational=False) == S.Reals
+    assert isolve(cos(x) < S(-2), x, relational=False) == S.EmptySet
+    assert isolve(sin(x) >= S.NegativeOne, x, relational=False) == S.Reals
+    assert isolve(cos(x) > S.One, x, relational=False) == S.EmptySet
+
+
+def test_issue_9954():
+    assert isolve(x**2 >= 0, x, relational=False) == S.Reals
+    assert isolve(x**2 >= 0, x, relational=True) == S.Reals.as_relational(x)
+    assert isolve(x**2 < 0, x, relational=False) == S.EmptySet
+    assert isolve(x**2 < 0, x, relational=True) == S.EmptySet.as_relational(x)
+
+
+@XFAIL
+def test_slow_general_univariate():
+    r = rootof(x**5 - x**2 + 1, 0)
+    assert solve(sqrt(x) + 1/root(x, 3) > 1) == \
+        Or(And(0 < x, x < r**6), And(r**6 < x, x < oo))
+
+
+def test_issue_8545():
+    eq = 1 - x - abs(1 - x)
+    ans = And(Lt(1, x), Lt(x, oo))
+    assert reduce_abs_inequality(eq, '<', x) == ans
+    eq = 1 - x - sqrt((1 - x)**2)
+    assert reduce_inequalities(eq < 0) == ans
+
+
+def test_issue_8974():
+    assert isolve(-oo < x, x) == And(-oo < x, x < oo)
+    assert isolve(oo > x, x) == And(-oo < x, x < oo)
+
+
+def test_issue_10198():
+    assert reduce_inequalities(
+        -1 + 1/abs(1/x - 1) < 0) == (x > -oo) & (x < S(1)/2) & Ne(x, 0)
+
+    assert reduce_inequalities(abs(1/sqrt(x)) - 1, x) == Eq(x, 1)
+    assert reduce_abs_inequality(-3 + 1/abs(1 - 1/x), '<', x) == \
+        Or(And(-oo < x, x < 0),
+        And(S.Zero < x, x < Rational(3, 4)), And(Rational(3, 2) < x, x < oo))
+    raises(ValueError,lambda: reduce_abs_inequality(-3 + 1/abs(
+        1 - 1/sqrt(x)), '<', x))
+
+
+def test_issue_10047():
+    # issue 10047: this must remain an inequality, not True, since if x
+    # is not real the inequality is invalid
+    # assert solve(sin(x) < 2) == (x <= oo)
+
+    # with PR 16956, (x <= oo) autoevaluates when x is extended_real
+    # which is assumed in the current implementation of inequality solvers
+    assert solve(sin(x) < 2) == True
+    assert solveset(sin(x) < 2, domain=S.Reals) == S.Reals
+
+
+def test_issue_10268():
+    assert solve(log(x) < 1000) == And(S.Zero < x, x < exp(1000))
+
+
+@XFAIL
+def test_isolve_Sets():
+    n = Dummy('n')
+    assert isolve(Abs(x) <= n, x, relational=False) == \
+        Piecewise((S.EmptySet, n < 0), (Interval(-n, n), True))
+
+
+def test_integer_domain_relational_isolve():
+
+    dom = FiniteSet(0, 3)
+    x = Symbol('x',zero=False)
+    assert isolve((x - 1)*(x - 2)*(x - 4) < 0, x, domain=dom) == Eq(x, 3)
+
+    x = Symbol('x')
+    assert isolve(x + 2 < 0, x, domain=S.Integers) == \
+           (x <= -3) & (x > -oo) & Eq(Mod(x, 1), 0)
+    assert isolve(2 * x + 3 > 0, x, domain=S.Integers) == \
+           (x >= -1) & (x < oo)  & Eq(Mod(x, 1), 0)
+    assert isolve((x ** 2 + 3 * x - 2) < 0, x, domain=S.Integers) == \
+           (x >= -3) & (x <= 0)  & Eq(Mod(x, 1), 0)
+    assert isolve((x ** 2 + 3 * x - 2) > 0, x, domain=S.Integers) == \
+           ((x >= 1) & (x < oo)  & Eq(Mod(x, 1), 0)) | (
+               (x <= -4) & (x > -oo)  & Eq(Mod(x, 1), 0))
+
+
+def test_issue_10671_12466():
+    assert solveset(sin(y), y, Interval(0, pi)) == FiniteSet(0, pi)
+    i = Interval(1, 10)
+    assert solveset((1/x).diff(x) < 0, x, i) == i
+    assert solveset((log(x - 6)/x) <= 0, x, S.Reals) == \
+        Interval.Lopen(6, 7)
+
+
+def test__solve_inequality():
+    for op in (Gt, Lt, Le, Ge, Eq, Ne):
+        assert _solve_inequality(op(x, 1), x).lhs == x
+        assert _solve_inequality(op(S.One, x), x).lhs == x
+    # don't get tricked by symbol on right: solve it
+    assert _solve_inequality(Eq(2*x - 1, x), x) == Eq(x, 1)
+    ie = Eq(S.One, y)
+    assert _solve_inequality(ie, x) == ie
+    for fx in (x**2, exp(x), sin(x) + cos(x), x*(1 + x)):
+        for c in (0, 1):
+            e = 2*fx - c > 0
+            assert _solve_inequality(e, x, linear=True) == (
+                fx > c/S(2))
+    assert _solve_inequality(2*x**2 + 2*x - 1 < 0, x, linear=True) == (
+        x*(x + 1) < S.Half)
+    assert _solve_inequality(Eq(x*y, 1), x) == Eq(x*y, 1)
+    nz = Symbol('nz', nonzero=True)
+    assert _solve_inequality(Eq(x*nz, 1), x) == Eq(x, 1/nz)
+    assert _solve_inequality(x*nz < 1, x) == (x*nz < 1)
+    a = Symbol('a', positive=True)
+    assert _solve_inequality(a/x > 1, x) == (S.Zero < x) & (x < a)
+    assert _solve_inequality(a/x > 1, x, linear=True) == (1/x > 1/a)
+    # make sure to include conditions under which solution is valid
+    e = Eq(1 - x, x*(1/x - 1))
+    assert _solve_inequality(e, x) == Ne(x, 0)
+    assert _solve_inequality(x < x*(1/x - 1), x) == (x < S.Half) & Ne(x, 0)
+
+
+def test__pt():
+    from sympy.solvers.inequalities import _pt
+    assert _pt(-oo, oo) == 0
+    assert _pt(S.One, S(3)) == 2
+    assert _pt(S.One, oo) == _pt(oo, S.One) == 2
+    assert _pt(S.One, -oo) == _pt(-oo, S.One) == S.Half
+    assert _pt(S.NegativeOne, oo) == _pt(oo, S.NegativeOne) == Rational(-1, 2)
+    assert _pt(S.NegativeOne, -oo) == _pt(-oo, S.NegativeOne) == -2
+    assert _pt(x, oo) == _pt(oo, x) == x + 1
+    assert _pt(x, -oo) == _pt(-oo, x) == x - 1
+    raises(ValueError, lambda: _pt(Dummy('i', infinite=True), S.One))
+
+
+def test_issue_25697():
+    assert _solve_inequality(log(x, 3) <= 2, x) == (x <= 9) & (S.Zero < x)
+
+
+def test_issue_25738():
+    assert reduce_inequalities(3 < abs(x)
+        ) == reduce_inequalities(pi < abs(x)).subs(pi, 3)
+
+
+def test_issue_25983():
+    assert(reduce_inequalities(pi/Abs(x) <= 1) == ((pi <= x) & (x < oo)) | ((-oo < x) & (x <= -pi)))

rl/Lib/site-packages/sympy/solvers/tests/test_numeric.py

@@ -0,0 +1,139 @@
+from sympy.core.function import nfloat
+from sympy.core.numbers import (Float, I, Rational, pi)
+from sympy.core.relational import Eq
+from sympy.core.symbol import (Symbol, symbols)
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.functions.elementary.piecewise import Piecewise
+from sympy.functions.elementary.trigonometric import sin
+from sympy.integrals.integrals import Integral
+from sympy.matrices.dense import Matrix
+from mpmath import mnorm, mpf
+from sympy.solvers import nsolve
+from sympy.utilities.lambdify import lambdify
+from sympy.testing.pytest import raises, XFAIL
+from sympy.utilities.decorator import conserve_mpmath_dps
+
+@XFAIL
+def test_nsolve_fail():
+    x = symbols('x')
+    # Sometimes it is better to use the numerator (issue 4829)
+    # but sometimes it is not (issue 11768) so leave this to
+    # the discretion of the user
+    ans = nsolve(x**2/(1 - x)/(1 - 2*x)**2 - 100, x, 0)
+    assert ans > 0.46 and ans < 0.47
+
+
+def test_nsolve_denominator():
+    x = symbols('x')
+    # Test that nsolve uses the full expression (numerator and denominator).
+    ans = nsolve((x**2 + 3*x + 2)/(x + 2), -2.1)
+    # The root -2 was divided out, so make sure we don't find it.
+    assert ans == -1.0
+
+def test_nsolve():
+    # onedimensional
+    x = Symbol('x')
+    assert nsolve(sin(x), 2) - pi.evalf() < 1e-15
+    assert nsolve(Eq(2*x, 2), x, -10) == nsolve(2*x - 2, -10)
+    # Testing checks on number of inputs
+    raises(TypeError, lambda: nsolve(Eq(2*x, 2)))
+    raises(TypeError, lambda: nsolve(Eq(2*x, 2), x, 1, 2))
+    # multidimensional
+    x1 = Symbol('x1')
+    x2 = Symbol('x2')
+    f1 = 3 * x1**2 - 2 * x2**2 - 1
+    f2 = x1**2 - 2 * x1 + x2**2 + 2 * x2 - 8
+    f = Matrix((f1, f2)).T
+    F = lambdify((x1, x2), f.T, modules='mpmath')
+    for x0 in [(-1, 1), (1, -2), (4, 4), (-4, -4)]:
+        x = nsolve(f, (x1, x2), x0, tol=1.e-8)
+        assert mnorm(F(*x), 1) <= 1.e-10
+    # The Chinese mathematician Zhu Shijie was the very first to solve this
+    # nonlinear system 700 years ago (z was added to make it 3-dimensional)
+    x = Symbol('x')
+    y = Symbol('y')
+    z = Symbol('z')
+    f1 = -x + 2*y
+    f2 = (x**2 + x*(y**2 - 2) - 4*y) / (x + 4)
+    f3 = sqrt(x**2 + y**2)*z
+    f = Matrix((f1, f2, f3)).T
+    F = lambdify((x, y, z), f.T, modules='mpmath')
+
+    def getroot(x0):
+        root = nsolve(f, (x, y, z), x0)
+        assert mnorm(F(*root), 1) <= 1.e-8
+        return root
+    assert list(map(round, getroot((1, 1, 1)))) == [2, 1, 0]
+    assert nsolve([Eq(
+        f1, 0), Eq(f2, 0), Eq(f3, 0)], [x, y, z], (1, 1, 1))  # just see that it works
+    a = Symbol('a')
+    assert abs(nsolve(1/(0.001 + a)**3 - 6/(0.9 - a)**3, a, 0.3) -
+        mpf('0.31883011387318591')) < 1e-15
+
+
+def test_issue_6408():
+    x = Symbol('x')
+    assert nsolve(Piecewise((x, x < 1), (x**2, True)), x, 2) == 0.0
+
+
+def test_issue_6408_integral():
+    x, y = symbols('x y')
+    assert nsolve(Integral(x*y, (x, 0, 5)), y, 2) == 0.0
+
+
+@conserve_mpmath_dps
+def test_increased_dps():
+    # Issue 8564
+    import mpmath
+    mpmath.mp.dps = 128
+    x = Symbol('x')
+    e1 = x**2 - pi
+    q = nsolve(e1, x, 3.0)
+
+    assert abs(sqrt(pi).evalf(128) - q) < 1e-128
+
+def test_nsolve_precision():
+    x, y = symbols('x y')
+    sol = nsolve(x**2 - pi, x, 3, prec=128)
+    assert abs(sqrt(pi).evalf(128) - sol) < 1e-128
+    assert isinstance(sol, Float)
+
+    sols = nsolve((y**2 - x, x**2 - pi), (x, y), (3, 3), prec=128)
+    assert isinstance(sols, Matrix)
+    assert sols.shape == (2, 1)
+    assert abs(sqrt(pi).evalf(128) - sols[0]) < 1e-128
+    assert abs(sqrt(sqrt(pi)).evalf(128) - sols[1]) < 1e-128
+    assert all(isinstance(i, Float) for i in sols)
+
+def test_nsolve_complex():
+    x, y = symbols('x y')
+
+    assert nsolve(x**2 + 2, 1j) == sqrt(2.)*I
+    assert nsolve(x**2 + 2, I) == sqrt(2.)*I
+
+    assert nsolve([x**2 + 2, y**2 + 2], [x, y], [I, I]) == Matrix([sqrt(2.)*I, sqrt(2.)*I])
+    assert nsolve([x**2 + 2, y**2 + 2], [x, y], [I, I]) == Matrix([sqrt(2.)*I, sqrt(2.)*I])
+
+def test_nsolve_dict_kwarg():
+    x, y = symbols('x y')
+    # one variable
+    assert nsolve(x**2 - 2, 1, dict = True) == \
+        [{x: sqrt(2.)}]
+    # one variable with complex solution
+    assert nsolve(x**2 + 2, I, dict = True) == \
+        [{x: sqrt(2.)*I}]
+    # two variables
+    assert nsolve([x**2 + y**2 - 5, x**2 - y**2 + 1], [x, y], [1, 1], dict = True) == \
+        [{x: sqrt(2.), y: sqrt(3.)}]
+
+def test_nsolve_rational():
+    x = symbols('x')
+    assert nsolve(x - Rational(1, 3), 0, prec=100) == Rational(1, 3).evalf(100)
+
+
+def test_issue_14950():
+    x = Matrix(symbols('t s'))
+    x0 = Matrix([17, 23])
+    eqn = x + x0
+    assert nsolve(eqn, x, x0) == nfloat(-x0)
+    assert nsolve(eqn.T, x.T, x0.T) == nfloat(-x0)

rl/Lib/site-packages/sympy/solvers/tests/test_pde.py

@@ -0,0 +1,239 @@
+from sympy.core.function import (Derivative as D, Function)
+from sympy.core.relational import Eq
+from sympy.core.symbol import (Symbol, symbols)
+from sympy.functions.elementary.exponential import (exp, log)
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.core import S
+from sympy.solvers.pde import (pde_separate, pde_separate_add, pde_separate_mul,
+    pdsolve, classify_pde, checkpdesol)
+from sympy.testing.pytest import raises
+
+
+a, b, c, x, y = symbols('a b c x y')
+
+def test_pde_separate_add():
+    x, y, z, t = symbols("x,y,z,t")
+    F, T, X, Y, Z, u = map(Function, 'FTXYZu')
+
+    eq = Eq(D(u(x, t), x), D(u(x, t), t)*exp(u(x, t)))
+    res = pde_separate_add(eq, u(x, t), [X(x), T(t)])
+    assert res == [D(X(x), x)*exp(-X(x)), D(T(t), t)*exp(T(t))]
+
+
+def test_pde_separate():
+    x, y, z, t = symbols("x,y,z,t")
+    F, T, X, Y, Z, u = map(Function, 'FTXYZu')
+
+    eq = Eq(D(u(x, t), x), D(u(x, t), t)*exp(u(x, t)))
+    raises(ValueError, lambda: pde_separate(eq, u(x, t), [X(x), T(t)], 'div'))
+
+
+def test_pde_separate_mul():
+    x, y, z, t = symbols("x,y,z,t")
+    c = Symbol("C", real=True)
+    Phi = Function('Phi')
+    F, R, T, X, Y, Z, u = map(Function, 'FRTXYZu')
+    r, theta, z = symbols('r,theta,z')
+
+    # Something simple :)
+    eq = Eq(D(F(x, y, z), x) + D(F(x, y, z), y) + D(F(x, y, z), z), 0)
+
+    # Duplicate arguments in functions
+    raises(
+        ValueError, lambda: pde_separate_mul(eq, F(x, y, z), [X(x), u(z, z)]))
+    # Wrong number of arguments
+    raises(ValueError, lambda: pde_separate_mul(eq, F(x, y, z), [X(x), Y(y)]))
+    # Wrong variables: [x, y] -> [x, z]
+    raises(
+        ValueError, lambda: pde_separate_mul(eq, F(x, y, z), [X(t), Y(x, y)]))
+
+    assert pde_separate_mul(eq, F(x, y, z), [Y(y), u(x, z)]) == \
+        [D(Y(y), y)/Y(y), -D(u(x, z), x)/u(x, z) - D(u(x, z), z)/u(x, z)]
+    assert pde_separate_mul(eq, F(x, y, z), [X(x), Y(y), Z(z)]) == \
+        [D(X(x), x)/X(x), -D(Z(z), z)/Z(z) - D(Y(y), y)/Y(y)]
+
+    # wave equation
+    wave = Eq(D(u(x, t), t, t), c**2*D(u(x, t), x, x))
+    res = pde_separate_mul(wave, u(x, t), [X(x), T(t)])
+    assert res == [D(X(x), x, x)/X(x), D(T(t), t, t)/(c**2*T(t))]
+
+    # Laplace equation in cylindrical coords
+    eq = Eq(1/r * D(Phi(r, theta, z), r) + D(Phi(r, theta, z), r, 2) +
+            1/r**2 * D(Phi(r, theta, z), theta, 2) + D(Phi(r, theta, z), z, 2), 0)
+    # Separate z
+    res = pde_separate_mul(eq, Phi(r, theta, z), [Z(z), u(theta, r)])
+    assert res == [D(Z(z), z, z)/Z(z),
+            -D(u(theta, r), r, r)/u(theta, r) -
+        D(u(theta, r), r)/(r*u(theta, r)) -
+        D(u(theta, r), theta, theta)/(r**2*u(theta, r))]
+    # Lets use the result to create a new equation...
+    eq = Eq(res[1], c)
+    # ...and separate theta...
+    res = pde_separate_mul(eq, u(theta, r), [T(theta), R(r)])
+    assert res == [D(T(theta), theta, theta)/T(theta),
+            -r*D(R(r), r)/R(r) - r**2*D(R(r), r, r)/R(r) - c*r**2]
+    # ...or r...
+    res = pde_separate_mul(eq, u(theta, r), [R(r), T(theta)])
+    assert res == [r*D(R(r), r)/R(r) + r**2*D(R(r), r, r)/R(r) + c*r**2,
+            -D(T(theta), theta, theta)/T(theta)]
+
+
+def test_issue_11726():
+    x, t = symbols("x t")
+    f  = symbols("f", cls=Function)
+    X, T = symbols("X T", cls=Function)
+
+    u = f(x, t)
+    eq = u.diff(x, 2) - u.diff(t, 2)
+    res = pde_separate(eq, u, [T(x), X(t)])
+    assert res == [D(T(x), x, x)/T(x),D(X(t), t, t)/X(t)]
+
+
+def test_pde_classify():
+    # When more number of hints are added, add tests for classifying here.
+    f = Function('f')
+    eq1 = a*f(x,y) + b*f(x,y).diff(x) + c*f(x,y).diff(y)
+    eq2 = 3*f(x,y) + 2*f(x,y).diff(x) + f(x,y).diff(y)
+    eq3 = a*f(x,y) + b*f(x,y).diff(x) + 2*f(x,y).diff(y)
+    eq4 = x*f(x,y) + f(x,y).diff(x) + 3*f(x,y).diff(y)
+    eq5 = x**2*f(x,y) + x*f(x,y).diff(x) + x*y*f(x,y).diff(y)
+    eq6 = y*x**2*f(x,y) + y*f(x,y).diff(x) + f(x,y).diff(y)
+    for eq in [eq1, eq2, eq3]:
+        assert classify_pde(eq) == ('1st_linear_constant_coeff_homogeneous',)
+    for eq in [eq4, eq5, eq6]:
+        assert classify_pde(eq) == ('1st_linear_variable_coeff',)
+
+
+def test_checkpdesol():
+    f, F = map(Function, ['f', 'F'])
+    eq1 = a*f(x,y) + b*f(x,y).diff(x) + c*f(x,y).diff(y)
+    eq2 = 3*f(x,y) + 2*f(x,y).diff(x) + f(x,y).diff(y)
+    eq3 = a*f(x,y) + b*f(x,y).diff(x) + 2*f(x,y).diff(y)
+    for eq in [eq1, eq2, eq3]:
+        assert checkpdesol(eq, pdsolve(eq))[0]
+    eq4 = x*f(x,y) + f(x,y).diff(x) + 3*f(x,y).diff(y)
+    eq5 = 2*f(x,y) + 1*f(x,y).diff(x) + 3*f(x,y).diff(y)
+    eq6 = f(x,y) + 1*f(x,y).diff(x) + 3*f(x,y).diff(y)
+    assert checkpdesol(eq4, [pdsolve(eq5), pdsolve(eq6)]) == [
+        (False, (x - 2)*F(3*x - y)*exp(-x/S(5) - 3*y/S(5))),
+         (False, (x - 1)*F(3*x - y)*exp(-x/S(10) - 3*y/S(10)))]
+    for eq in [eq4, eq5, eq6]:
+        assert checkpdesol(eq, pdsolve(eq))[0]
+    sol = pdsolve(eq4)
+    sol4 = Eq(sol.lhs - sol.rhs, 0)
+    raises(NotImplementedError, lambda:
+        checkpdesol(eq4, sol4, solve_for_func=False))
+
+
+def test_solvefun():
+    f, F, G, H = map(Function, ['f', 'F', 'G', 'H'])
+    eq1 = f(x,y) + f(x,y).diff(x) + f(x,y).diff(y)
+    assert pdsolve(eq1) == Eq(f(x, y), F(x - y)*exp(-x/2 - y/2))
+    assert pdsolve(eq1, solvefun=G) == Eq(f(x, y), G(x - y)*exp(-x/2 - y/2))
+    assert pdsolve(eq1, solvefun=H) == Eq(f(x, y), H(x - y)*exp(-x/2 - y/2))
+
+
+def test_pde_1st_linear_constant_coeff_homogeneous():
+    f, F = map(Function, ['f', 'F'])
+    u = f(x, y)
+    eq = 2*u + u.diff(x) + u.diff(y)
+    assert classify_pde(eq) == ('1st_linear_constant_coeff_homogeneous',)
+    sol = pdsolve(eq)
+    assert sol == Eq(u, F(x - y)*exp(-x - y))
+    assert checkpdesol(eq, sol)[0]
+
+    eq = 4 + (3*u.diff(x)/u) + (2*u.diff(y)/u)
+    assert classify_pde(eq) == ('1st_linear_constant_coeff_homogeneous',)
+    sol = pdsolve(eq)
+    assert sol == Eq(u, F(2*x - 3*y)*exp(-S(12)*x/13 - S(8)*y/13))
+    assert checkpdesol(eq, sol)[0]
+
+    eq = u + (6*u.diff(x)) + (7*u.diff(y))
+    assert classify_pde(eq) == ('1st_linear_constant_coeff_homogeneous',)
+    sol = pdsolve(eq)
+    assert sol == Eq(u, F(7*x - 6*y)*exp(-6*x/S(85) - 7*y/S(85)))
+    assert checkpdesol(eq, sol)[0]
+
+    eq = a*u + b*u.diff(x) + c*u.diff(y)
+    sol = pdsolve(eq)
+    assert checkpdesol(eq, sol)[0]
+
+
+def test_pde_1st_linear_constant_coeff():
+    f, F = map(Function, ['f', 'F'])
+    u = f(x,y)
+    eq = -2*u.diff(x) + 4*u.diff(y) + 5*u - exp(x + 3*y)
+    sol = pdsolve(eq)
+    assert sol == Eq(f(x,y),
+    (F(4*x + 2*y)*exp(x/2) + exp(x + 4*y)/15)*exp(-y))
+    assert classify_pde(eq) == ('1st_linear_constant_coeff',
+    '1st_linear_constant_coeff_Integral')
+    assert checkpdesol(eq, sol)[0]
+
+    eq = (u.diff(x)/u) + (u.diff(y)/u) + 1 - (exp(x + y)/u)
+    sol = pdsolve(eq)
+    assert sol == Eq(f(x, y), F(x - y)*exp(-x/2 - y/2) + exp(x + y)/3)
+    assert classify_pde(eq) == ('1st_linear_constant_coeff',
+    '1st_linear_constant_coeff_Integral')
+    assert checkpdesol(eq, sol)[0]
+
+    eq = 2*u + -u.diff(x) + 3*u.diff(y) + sin(x)
+    sol = pdsolve(eq)
+    assert sol == Eq(f(x, y),
+         F(3*x + y)*exp(x/5 - 3*y/5) - 2*sin(x)/5 - cos(x)/5)
+    assert classify_pde(eq) == ('1st_linear_constant_coeff',
+    '1st_linear_constant_coeff_Integral')
+    assert checkpdesol(eq, sol)[0]
+
+    eq = u + u.diff(x) + u.diff(y) + x*y
+    sol = pdsolve(eq)
+    assert sol.expand() == Eq(f(x, y),
+        x + y + (x - y)**2/4 - (x + y)**2/4 + F(x - y)*exp(-x/2 - y/2) - 2).expand()
+    assert classify_pde(eq) == ('1st_linear_constant_coeff',
+    '1st_linear_constant_coeff_Integral')
+    assert checkpdesol(eq, sol)[0]
+    eq = u + u.diff(x) + u.diff(y) + log(x)
+    assert classify_pde(eq) == ('1st_linear_constant_coeff',
+    '1st_linear_constant_coeff_Integral')
+
+
+def test_pdsolve_all():
+    f, F = map(Function, ['f', 'F'])
+    u = f(x,y)
+    eq = u + u.diff(x) + u.diff(y) + x**2*y
+    sol = pdsolve(eq, hint = 'all')
+    keys = ['1st_linear_constant_coeff',
+        '1st_linear_constant_coeff_Integral', 'default', 'order']
+    assert sorted(sol.keys()) == keys
+    assert sol['order'] == 1
+    assert sol['default'] == '1st_linear_constant_coeff'
+    assert sol['1st_linear_constant_coeff'].expand() == Eq(f(x, y),
+        -x**2*y + x**2 + 2*x*y - 4*x - 2*y + F(x - y)*exp(-x/2 - y/2) + 6).expand()
+
+
+def test_pdsolve_variable_coeff():
+    f, F = map(Function, ['f', 'F'])
+    u = f(x, y)
+    eq = x*(u.diff(x)) - y*(u.diff(y)) + y**2*u - y**2
+    sol = pdsolve(eq, hint="1st_linear_variable_coeff")
+    assert sol == Eq(u, F(x*y)*exp(y**2/2) + 1)
+    assert checkpdesol(eq, sol)[0]
+
+    eq = x**2*u + x*u.diff(x) + x*y*u.diff(y)
+    sol = pdsolve(eq, hint='1st_linear_variable_coeff')
+    assert sol == Eq(u, F(y*exp(-x))*exp(-x**2/2))
+    assert checkpdesol(eq, sol)[0]
+
+    eq = y*x**2*u + y*u.diff(x) + u.diff(y)
+    sol = pdsolve(eq, hint='1st_linear_variable_coeff')
+    assert sol == Eq(u, F(-2*x + y**2)*exp(-x**3/3))
+    assert checkpdesol(eq, sol)[0]
+
+    eq = exp(x)**2*(u.diff(x)) + y
+    sol = pdsolve(eq, hint='1st_linear_variable_coeff')
+    assert sol == Eq(u, y*exp(-2*x)/2 + F(y))
+    assert checkpdesol(eq, sol)[0]
+
+    eq = exp(2*x)*(u.diff(y)) + y*u - u
+    sol = pdsolve(eq, hint='1st_linear_variable_coeff')
+    assert sol == Eq(u, F(x)*exp(-y*(y - 2)*exp(-2*x)/2))

rl/Lib/site-packages/sympy/solvers/tests/test_polysys.py

@@ -0,0 +1,178 @@
+"""Tests for solvers of systems of polynomial equations. """
+from sympy.core.numbers import (I, Integer, Rational)
+from sympy.core.singleton import S
+from sympy.core.symbol import symbols
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.polys.domains.rationalfield import QQ
+from sympy.polys.polyerrors import UnsolvableFactorError
+from sympy.polys.polyoptions import Options
+from sympy.polys.polytools import Poly
+from sympy.solvers.solvers import solve
+from sympy.utilities.iterables import flatten
+from sympy.abc import x, y, z
+from sympy.polys import PolynomialError
+from sympy.solvers.polysys import (solve_poly_system,
+                                   solve_triangulated,
+                                   solve_biquadratic, SolveFailed,
+                                   solve_generic)
+from sympy.polys.polytools import parallel_poly_from_expr
+from sympy.testing.pytest import raises
+
+
+def test_solve_poly_system():
+    assert solve_poly_system([x - 1], x) == [(S.One,)]
+
+    assert solve_poly_system([y - x, y - x - 1], x, y) is None
+
+    assert solve_poly_system([y - x**2, y + x**2], x, y) == [(S.Zero, S.Zero)]
+
+    assert solve_poly_system([2*x - 3, y*Rational(3, 2) - 2*x, z - 5*y], x, y, z) == \
+        [(Rational(3, 2), Integer(2), Integer(10))]
+
+    assert solve_poly_system([x*y - 2*y, 2*y**2 - x**2], x, y) == \
+        [(0, 0), (2, -sqrt(2)), (2, sqrt(2))]
+
+    assert solve_poly_system([y - x**2, y + x**2 + 1], x, y) == \
+        [(-I*sqrt(S.Half), Rational(-1, 2)), (I*sqrt(S.Half), Rational(-1, 2))]
+
+    f_1 = x**2 + y + z - 1
+    f_2 = x + y**2 + z - 1
+    f_3 = x + y + z**2 - 1
+
+    a, b = sqrt(2) - 1, -sqrt(2) - 1
+
+    assert solve_poly_system([f_1, f_2, f_3], x, y, z) == \
+        [(0, 0, 1), (0, 1, 0), (1, 0, 0), (a, a, a), (b, b, b)]
+
+    solution = [(1, -1), (1, 1)]
+
+    assert solve_poly_system([Poly(x**2 - y**2), Poly(x - 1)]) == solution
+    assert solve_poly_system([x**2 - y**2, x - 1], x, y) == solution
+    assert solve_poly_system([x**2 - y**2, x - 1]) == solution
+
+    assert solve_poly_system(
+        [x + x*y - 3, y + x*y - 4], x, y) == [(-3, -2), (1, 2)]
+
+    raises(NotImplementedError, lambda: solve_poly_system([x**3 - y**3], x, y))
+    raises(NotImplementedError, lambda: 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)))
+
+    # solve_poly_system should ideally construct solutions using
+    # CRootOf for the following four tests
+    assert solve_poly_system([x**5 - x + 1], [x], strict=False) == []
+    raises(UnsolvableFactorError, lambda: solve_poly_system(
+        [x**5 - x + 1], [x], strict=True))
+
+    assert solve_poly_system([(x - 1)*(x**5 - x + 1), y**2 - 1], [x, y],
+                             strict=False) == [(1, -1), (1, 1)]
+    raises(UnsolvableFactorError,
+           lambda: solve_poly_system([(x - 1)*(x**5 - x + 1), y**2-1],
+                                     [x, y], strict=True))
+
+
+def test_solve_generic():
+    NewOption = Options((x, y), {'domain': 'ZZ'})
+    assert solve_generic([x**2 - 2*y**2, y**2 - y + 1], NewOption) == \
+           [(-sqrt(-1 - sqrt(3)*I), Rational(1, 2) - sqrt(3)*I/2),
+            (sqrt(-1 - sqrt(3)*I), Rational(1, 2) - sqrt(3)*I/2),
+            (-sqrt(-1 + sqrt(3)*I), Rational(1, 2) + sqrt(3)*I/2),
+            (sqrt(-1 + sqrt(3)*I), Rational(1, 2) + sqrt(3)*I/2)]
+
+    # solve_generic should ideally construct solutions using
+    # CRootOf for the following two tests
+    assert solve_generic(
+        [2*x - y, (y - 1)*(y**5 - y + 1)], NewOption, strict=False) == \
+        [(Rational(1, 2), 1)]
+    raises(UnsolvableFactorError, lambda: solve_generic(
+        [2*x - y, (y - 1)*(y**5 - y + 1)], NewOption, strict=True))
+
+
+def test_solve_biquadratic():
+    x0, y0, x1, y1, r = symbols('x0 y0 x1 y1 r')
+
+    f_1 = (x - 1)**2 + (y - 1)**2 - r**2
+    f_2 = (x - 2)**2 + (y - 2)**2 - r**2
+    s = sqrt(2*r**2 - 1)
+    a = (3 - s)/2
+    b = (3 + s)/2
+    assert solve_poly_system([f_1, f_2], x, y) == [(a, b), (b, a)]
+
+    f_1 = (x - 1)**2 + (y - 2)**2 - r**2
+    f_2 = (x - 1)**2 + (y - 1)**2 - r**2
+
+    assert solve_poly_system([f_1, f_2], x, y) == \
+        [(1 - sqrt((2*r - 1)*(2*r + 1))/2, Rational(3, 2)),
+         (1 + sqrt((2*r - 1)*(2*r + 1))/2, Rational(3, 2))]
+
+    query = lambda expr: expr.is_Pow and expr.exp is S.Half
+
+    f_1 = (x - 1 )**2 + (y - 2)**2 - r**2
+    f_2 = (x - x1)**2 + (y - 1)**2 - r**2
+
+    result = solve_poly_system([f_1, f_2], x, y)
+
+    assert len(result) == 2 and all(len(r) == 2 for r in result)
+    assert all(r.count(query) == 1 for r in flatten(result))
+
+    f_1 = (x - x0)**2 + (y - y0)**2 - r**2
+    f_2 = (x - x1)**2 + (y - y1)**2 - r**2
+
+    result = solve_poly_system([f_1, f_2], x, y)
+
+    assert len(result) == 2 and all(len(r) == 2 for r in result)
+    assert all(len(r.find(query)) == 1 for r in flatten(result))
+
+    s1 = (x*y - y, x**2 - x)
+    assert solve(s1) == [{x: 1}, {x: 0, y: 0}]
+    s2 = (x*y - x, y**2 - y)
+    assert solve(s2) == [{y: 1}, {x: 0, y: 0}]
+    gens = (x, y)
+    for seq in (s1, s2):
+        (f, g), opt = parallel_poly_from_expr(seq, *gens)
+        raises(SolveFailed, lambda: solve_biquadratic(f, g, opt))
+    seq = (x**2 + y**2 - 2, y**2 - 1)
+    (f, g), opt = parallel_poly_from_expr(seq, *gens)
+    assert solve_biquadratic(f, g, opt) == [
+        (-1, -1), (-1, 1), (1, -1), (1, 1)]
+    ans = [(0, -1), (0, 1)]
+    seq = (x**2 + y**2 - 1, y**2 - 1)
+    (f, g), opt = parallel_poly_from_expr(seq, *gens)
+    assert solve_biquadratic(f, g, opt) == ans
+    seq = (x**2 + y**2 - 1, x**2 - x + y**2 - 1)
+    (f, g), opt = parallel_poly_from_expr(seq, *gens)
+    assert solve_biquadratic(f, g, opt) == ans
+
+
+def test_solve_triangulated():
+    f_1 = x**2 + y + z - 1
+    f_2 = x + y**2 + z - 1
+    f_3 = x + y + z**2 - 1
+
+    a, b = sqrt(2) - 1, -sqrt(2) - 1
+
+    assert solve_triangulated([f_1, f_2, f_3], x, y, z) == \
+        [(0, 0, 1), (0, 1, 0), (1, 0, 0)]
+
+    dom = QQ.algebraic_field(sqrt(2))
+
+    assert solve_triangulated([f_1, f_2, f_3], x, y, z, domain=dom) == \
+        [(0, 0, 1), (0, 1, 0), (1, 0, 0), (a, a, a), (b, b, b)]
+
+
+def test_solve_issue_3686():
+    roots = solve_poly_system([((x - 5)**2/250000 + (y - Rational(5, 10))**2/250000) - 1, x], x, y)
+    assert roots == [(0, S.Half - 15*sqrt(1111)), (0, S.Half + 15*sqrt(1111))]
+
+    roots = solve_poly_system([((x - 5)**2/250000 + (y - 5.0/10)**2/250000) - 1, x], x, y)
+    # TODO: does this really have to be so complicated?!
+    assert len(roots) == 2
+    assert roots[0][0] == 0
+    assert roots[0][1].epsilon_eq(-499.474999374969, 1e12)
+    assert roots[1][0] == 0
+    assert roots[1][1].epsilon_eq(500.474999374969, 1e12)

rl/Lib/site-packages/sympy/solvers/tests/test_recurr.py

@@ -0,0 +1,295 @@
+from sympy.core.function import (Function, Lambda, expand)
+from sympy.core.numbers import (I, Rational)
+from sympy.core.relational import Eq
+from sympy.core.singleton import S
+from sympy.core.symbol import (Symbol, symbols)
+from sympy.functions.combinatorial.factorials import (rf, binomial, factorial)
+from sympy.functions.elementary.complexes import Abs
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.functions.elementary.trigonometric import (cos, sin)
+from sympy.polys.polytools import factor
+from sympy.solvers.recurr import rsolve, rsolve_hyper, rsolve_poly, rsolve_ratio
+from sympy.testing.pytest import raises, slow, XFAIL
+from sympy.abc import a, b
+
+y = Function('y')
+n, k = symbols('n,k', integer=True)
+C0, C1, C2 = symbols('C0,C1,C2')
+
+
+def test_rsolve_poly():
+    assert rsolve_poly([-1, -1, 1], 0, n) == 0
+    assert rsolve_poly([-1, -1, 1], 1, n) == -1
+
+    assert rsolve_poly([-1, n + 1], n, n) == 1
+    assert rsolve_poly([-1, 1], n, n) == C0 + (n**2 - n)/2
+    assert rsolve_poly([-n - 1, n], 1, n) == C0*n - 1
+    assert rsolve_poly([-4*n - 2, 1], 4*n + 1, n) == -1
+
+    assert rsolve_poly([-1, 1], n**5 + n**3, n) == \
+        C0 - n**3 / 2 - n**5 / 2 + n**2 / 6 + n**6 / 6 + 2*n**4 / 3
+
+
+def test_rsolve_ratio():
+    solution = rsolve_ratio([-2*n**3 + n**2 + 2*n - 1, 2*n**3 + n**2 - 6*n,
+        -2*n**3 - 11*n**2 - 18*n - 9, 2*n**3 + 13*n**2 + 22*n + 8], 0, n)
+    assert solution == C0*(2*n - 3)/(n**2 - 1)/2
+
+
+def test_rsolve_hyper():
+    assert rsolve_hyper([-1, -1, 1], 0, n) in [
+        C0*(S.Half - S.Half*sqrt(5))**n + C1*(S.Half + S.Half*sqrt(5))**n,
+        C1*(S.Half - S.Half*sqrt(5))**n + C0*(S.Half + S.Half*sqrt(5))**n,
+    ]
+
+    assert rsolve_hyper([n**2 - 2, -2*n - 1, 1], 0, n) in [
+        C0*rf(sqrt(2), n) + C1*rf(-sqrt(2), n),
+        C1*rf(sqrt(2), n) + C0*rf(-sqrt(2), n),
+    ]
+
+    assert rsolve_hyper([n**2 - k, -2*n - 1, 1], 0, n) in [
+        C0*rf(sqrt(k), n) + C1*rf(-sqrt(k), n),
+        C1*rf(sqrt(k), n) + C0*rf(-sqrt(k), n),
+    ]
+
+    assert rsolve_hyper(
+        [2*n*(n + 1), -n**2 - 3*n + 2, n - 1], 0, n) == C1*factorial(n) + C0*2**n
+
+    assert rsolve_hyper(
+        [n + 2, -(2*n + 3)*(17*n**2 + 51*n + 39), n + 1], 0, n) == 0
+
+    assert rsolve_hyper([-n - 1, -1, 1], 0, n) == 0
+
+    assert rsolve_hyper([-1, 1], n, n).expand() == C0 + n**2/2 - n/2
+
+    assert rsolve_hyper([-1, 1], 1 + n, n).expand() == C0 + n**2/2 + n/2
+
+    assert rsolve_hyper([-1, 1], 3*(n + n**2), n).expand() == C0 + n**3 - n
+
+    assert rsolve_hyper([-a, 1],0,n).expand() == C0*a**n
+
+    assert rsolve_hyper([-a, 0, 1], 0, n).expand() == (-1)**n*C1*a**(n/2) + C0*a**(n/2)
+
+    assert rsolve_hyper([1, 1, 1], 0, n).expand() == \
+        C0*(Rational(-1, 2) - sqrt(3)*I/2)**n + C1*(Rational(-1, 2) + sqrt(3)*I/2)**n
+
+    assert rsolve_hyper([1, -2*n/a - 2/a, 1], 0, n) == 0
+
+
+@XFAIL
+def test_rsolve_ratio_missed():
+    # this arises during computation
+    # assert rsolve_hyper([-1, 1], 3*(n + n**2), n).expand() == C0 + n**3 - n
+    assert rsolve_ratio([-n, n + 2], n, n) is not None
+
+
+def recurrence_term(c, f):
+    """Compute RHS of recurrence in f(n) with coefficients in c."""
+    return sum(c[i]*f.subs(n, n + i) for i in range(len(c)))
+
+
+def test_rsolve_bulk():
+    """Some bulk-generated tests."""
+    funcs = [ n, n + 1, n**2, n**3, n**4, n + n**2, 27*n + 52*n**2 - 3*
+        n**3 + 12*n**4 - 52*n**5 ]
+    coeffs = [ [-2, 1], [-2, -1, 1], [-1, 1, 1, -1, 1], [-n, 1], [n**2 -
+        n + 12, 1] ]
+    for p in funcs:
+        # compute difference
+        for c in coeffs:
+            q = recurrence_term(c, p)
+            if p.is_polynomial(n):
+                assert rsolve_poly(c, q, n) == p
+            # See issue 3956:
+            if p.is_hypergeometric(n) and len(c) <= 3:
+                assert rsolve_hyper(c, q, n).subs(zip(symbols('C:3'), [0, 0, 0])).expand() == p
+
+
+def test_rsolve_0_sol_homogeneous():
+    # fixed by cherry-pick from
+    # https://github.com/diofant/diofant/commit/e1d2e52125199eb3df59f12e8944f8a5f24b00a5
+    assert rsolve_hyper([n**2 - n + 12, 1], n*(n**2 - n + 12) + n + 1, n) == n
+
+
+def test_rsolve():
+    f = y(n + 2) - y(n + 1) - y(n)
+    h = sqrt(5)*(S.Half + S.Half*sqrt(5))**n \
+        - sqrt(5)*(S.Half - S.Half*sqrt(5))**n
+
+    assert rsolve(f, y(n)) in [
+        C0*(S.Half - S.Half*sqrt(5))**n + C1*(S.Half + S.Half*sqrt(5))**n,
+        C1*(S.Half - S.Half*sqrt(5))**n + C0*(S.Half + S.Half*sqrt(5))**n,
+    ]
+
+    assert rsolve(f, y(n), [0, 5]) == h
+    assert rsolve(f, y(n), {0: 0, 1: 5}) == h
+    assert rsolve(f, y(n), {y(0): 0, y(1): 5}) == h
+    assert rsolve(y(n) - y(n - 1) - y(n - 2), y(n), [0, 5]) == h
+    assert rsolve(Eq(y(n), y(n - 1) + y(n - 2)), y(n), [0, 5]) == h
+
+    assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
+
+    f = (n - 1)*y(n + 2) - (n**2 + 3*n - 2)*y(n + 1) + 2*n*(n + 1)*y(n)
+    g = C1*factorial(n) + C0*2**n
+    h = -3*factorial(n) + 3*2**n
+
+    assert rsolve(f, y(n)) == g
+    assert rsolve(f, y(n), []) == g
+    assert rsolve(f, y(n), {}) == g
+
+    assert rsolve(f, y(n), [0, 3]) == h
+    assert rsolve(f, y(n), {0: 0, 1: 3}) == h
+    assert rsolve(f, y(n), {y(0): 0, y(1): 3}) == h
+
+    assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
+
+    f = y(n) - y(n - 1) - 2
+
+    assert rsolve(f, y(n), {y(0): 0}) == 2*n
+    assert rsolve(f, y(n), {y(0): 1}) == 2*n + 1
+    assert rsolve(f, y(n), {y(0): 0, y(1): 1}) is None
+
+    assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
+
+    f = 3*y(n - 1) - y(n) - 1
+
+    assert rsolve(f, y(n), {y(0): 0}) == -3**n/2 + S.Half
+    assert rsolve(f, y(n), {y(0): 1}) == 3**n/2 + S.Half
+    assert rsolve(f, y(n), {y(0): 2}) == 3*3**n/2 + S.Half
+
+    assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
+
+    f = y(n) - 1/n*y(n - 1)
+    assert rsolve(f, y(n)) == C0/factorial(n)
+    assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
+
+    f = y(n) - 1/n*y(n - 1) - 1
+    assert rsolve(f, y(n)) is None
+
+    f = 2*y(n - 1) + (1 - n)*y(n)/n
+
+    assert rsolve(f, y(n), {y(1): 1}) == 2**(n - 1)*n
+    assert rsolve(f, y(n), {y(1): 2}) == 2**(n - 1)*n*2
+    assert rsolve(f, y(n), {y(1): 3}) == 2**(n - 1)*n*3
+
+    assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
+
+    f = (n - 1)*(n - 2)*y(n + 2) - (n + 1)*(n + 2)*y(n)
+
+    assert rsolve(f, y(n), {y(3): 6, y(4): 24}) == n*(n - 1)*(n - 2)
+    assert rsolve(
+        f, y(n), {y(3): 6, y(4): -24}) == -n*(n - 1)*(n - 2)*(-1)**(n)
+
+    assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
+
+    assert rsolve(Eq(y(n + 1), a*y(n)), y(n), {y(1): a}).simplify() == a**n
+
+    assert rsolve(y(n) - a*y(n-2),y(n), \
+            {y(1): sqrt(a)*(a + b), y(2): a*(a - b)}).simplify() == \
+            a**(n/2 + 1) - b*(-sqrt(a))**n
+
+    f = (-16*n**2 + 32*n - 12)*y(n - 1) + (4*n**2 - 12*n + 9)*y(n)
+
+    yn = rsolve(f, y(n), {y(1): binomial(2*n + 1, 3)})
+    sol = 2**(2*n)*n*(2*n - 1)**2*(2*n + 1)/12
+    assert factor(expand(yn, func=True)) == sol
+
+    sol = rsolve(y(n) + a*(y(n + 1) + y(n - 1))/2, y(n))
+    assert str(sol) == 'C0*((-sqrt(1 - a**2) - 1)/a)**n + C1*((sqrt(1 - a**2) - 1)/a)**n'
+
+    assert rsolve((k + 1)*y(k), y(k)) is None
+    assert (rsolve((k + 1)*y(k) + (k + 3)*y(k + 1) + (k + 5)*y(k + 2), y(k))
+            is None)
+
+    assert rsolve(y(n) + y(n + 1) + 2**n + 3**n, y(n)) == (-1)**n*C0 - 2**n/3 - 3**n/4
+
+
+def test_rsolve_raises():
+    x = Function('x')
+    raises(ValueError, lambda: rsolve(y(n) - y(k + 1), y(n)))
+    raises(ValueError, lambda: rsolve(y(n) - y(n + 1), x(n)))
+    raises(ValueError, lambda: rsolve(y(n) - x(n + 1), y(n)))
+    raises(ValueError, lambda: rsolve(y(n) - sqrt(n)*y(n + 1), y(n)))
+    raises(ValueError, lambda: rsolve(y(n) - y(n + 1), y(n), {x(0): 0}))
+    raises(ValueError, lambda: rsolve(y(n) + y(n + 1) + 2**n + cos(n), y(n)))
+
+
+def test_issue_6844():
+    f = y(n + 2) - y(n + 1) + y(n)/4
+    assert rsolve(f, y(n)) == 2**(-n + 1)*C1*n + 2**(-n)*C0
+    assert rsolve(f, y(n), {y(0): 0, y(1): 1}) == 2**(1 - n)*n
+
+
+def test_issue_18751():
+    r = Symbol('r', positive=True)
+    theta = Symbol('theta', real=True)
+    f = y(n) - 2 * r * cos(theta) * y(n - 1) + r**2 * y(n - 2)
+    assert rsolve(f, y(n)) == \
+        C0*(r*(cos(theta) - I*Abs(sin(theta))))**n + C1*(r*(cos(theta) + I*Abs(sin(theta))))**n
+
+
+def test_constant_naming():
+    #issue 8697
+    assert rsolve(y(n+3) - y(n+2) - y(n+1) + y(n), y(n)) == (-1)**n*C1 + C0 + C2*n
+    assert rsolve(y(n+3)+3*y(n+2)+3*y(n+1)+y(n), y(n)).expand() == (-1)**n*C0 - (-1)**n*C1*n - (-1)**n*C2*n**2
+    assert rsolve(y(n) - 2*y(n - 3) + 5*y(n - 2) - 4*y(n - 1),y(n),[1,3,8]) == 3*2**n - n - 2
+
+    #issue 19630
+    assert rsolve(y(n+3) - 3*y(n+1) + 2*y(n), y(n), {y(1):0, y(2):8, y(3):-2}) == (-2)**n + 2*n
+
+
+@slow
+def test_issue_15751():
+    f = y(n) + 21*y(n + 1) - 273*y(n + 2) - 1092*y(n + 3) + 1820*y(n + 4) + 1092*y(n + 5) - 273*y(n + 6) - 21*y(n + 7) + y(n + 8)
+    assert rsolve(f, y(n)) is not None
+
+
+def test_issue_17990():
+    f = -10*y(n) + 4*y(n + 1) + 6*y(n + 2) + 46*y(n + 3)
+    sol = rsolve(f, y(n))
+    expected = C0*((86*18**(S(1)/3)/69 + (-12 + (-1 + sqrt(3)*I)*(290412 +
+        3036*sqrt(9165))**(S(1)/3))*(1 - sqrt(3)*I)*(24201 + 253*sqrt(9165))**
+        (S(1)/3)/276)/((1 - sqrt(3)*I)*(24201 + 253*sqrt(9165))**(S(1)/3))
+        )**n + C1*((86*18**(S(1)/3)/69 + (-12 + (-1 - sqrt(3)*I)*(290412 + 3036
+        *sqrt(9165))**(S(1)/3))*(1 + sqrt(3)*I)*(24201 + 253*sqrt(9165))**
+        (S(1)/3)/276)/((1 + sqrt(3)*I)*(24201 + 253*sqrt(9165))**(S(1)/3))
+        )**n + C2*(-43*18**(S(1)/3)/(69*(24201 + 253*sqrt(9165))**(S(1)/3)) -
+        S(1)/23 + (290412 + 3036*sqrt(9165))**(S(1)/3)/138)**n
+    assert sol == expected
+    e = sol.subs({C0: 1, C1: 1, C2: 1, n: 1}).evalf()
+    assert abs(e + 0.130434782608696) < 1e-13
+
+
+def test_issue_8697():
+    a = Function('a')
+    eq = a(n + 3) - a(n + 2) - a(n + 1) + a(n)
+    assert rsolve(eq, a(n)) == (-1)**n*C1 + C0 + C2*n
+    eq2 = a(n + 3) + 3*a(n + 2) + 3*a(n + 1) + a(n)
+    assert (rsolve(eq2, a(n)) ==
+            (-1)**n*C0 + (-1)**(n + 1)*C1*n + (-1)**(n + 1)*C2*n**2)
+
+    assert rsolve(a(n) - 2*a(n - 3) + 5*a(n - 2) - 4*a(n - 1),
+                  a(n), {a(0): 1, a(1): 3, a(2): 8}) == 3*2**n - n - 2
+
+    # From issue thread (but fixed by https://github.com/diofant/diofant/commit/da9789c6cd7d0c2ceeea19fbf59645987125b289):
+    assert rsolve(a(n) - 2*a(n - 1) - n, a(n), {a(0): 1}) == 3*2**n - n - 2
+
+
+def test_diofantissue_294():
+    f = y(n) - y(n - 1) - 2*y(n - 2) - 2*n
+    assert rsolve(f, y(n)) == (-1)**n*C0 + 2**n*C1 - n - Rational(5, 2)
+    # issue sympy/sympy#11261
+    assert rsolve(f, y(n), {y(0): -1, y(1): 1}) == (-(-1)**n/2 + 2*2**n -
+                                                    n - Rational(5, 2))
+    # issue sympy/sympy#7055
+    assert rsolve(-2*y(n) + y(n + 1) + n - 1, y(n)) == 2**n*C0 + n
+
+
+def test_issue_15553():
+    f = Function("f")
+    assert rsolve(Eq(f(n), 2*f(n - 1) + n), f(n)) == 2**n*C0 - n - 2
+    assert rsolve(Eq(f(n + 1), 2*f(n) + n**2 + 1), f(n)) == 2**n*C0 - n**2 - 2*n - 4
+    assert rsolve(Eq(f(n + 1), 2*f(n) + n**2 + 1), f(n), {f(1): 0}) == 7*2**n/2 - n**2 - 2*n - 4
+    assert rsolve(Eq(f(n), 2*f(n - 1) + 3*n**2), f(n)) == 2**n*C0 - 3*n**2 - 12*n - 18
+    assert rsolve(Eq(f(n), 2*f(n - 1) + n**2), f(n)) == 2**n*C0 - n**2 - 4*n - 6
+    assert rsolve(Eq(f(n), 2*f(n - 1) + n), f(n), {f(0): 1}) == 3*2**n - n - 2

rl/Lib/site-packages/sympy/solvers/tests/test_simplex.py

@@ -0,0 +1,254 @@
+from sympy.core.numbers import Rational
+from sympy.core.relational import Eq, Ne
+from sympy.core.symbol import symbols
+from sympy.core.sympify import sympify
+from sympy.core.singleton import S
+from sympy.core.random import random, choice
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.ntheory.generate import randprime
+from sympy.matrices.dense import Matrix
+from sympy.solvers.solveset import linear_eq_to_matrix
+from sympy.solvers.simplex import (_lp as lp, _primal_dual,
+    UnboundedLPError, InfeasibleLPError, lpmin, lpmax,
+    _m, _abcd, _simplex, linprog)
+
+from sympy.external.importtools import import_module
+
+from sympy.testing.pytest import raises
+
+from sympy.abc import x, y, z
+
+
+np = import_module("numpy")
+scipy = import_module("scipy")
+
+
+def test_lp():
+    r1 = y + 2*z <= 3
+    r2 = -x - 3*z <= -2
+    r3 = 2*x + y + 7*z <= 5
+    constraints = [r1, r2, r3, x >= 0, y >= 0, z >= 0]
+    objective = -x - y - 5 * z
+    ans = optimum, argmax = lp(max, objective, constraints)
+    assert ans == lpmax(objective, constraints)
+    assert objective.subs(argmax) == optimum
+    for constr in constraints:
+        assert constr.subs(argmax) == True
+
+    r1 = x - y + 2*z <= 3
+    r2 = -x + 2*y - 3*z <= -2
+    r3 = 2*x + y - 7*z <= -5
+    constraints = [r1, r2, r3, x >= 0, y >= 0, z >= 0]
+    objective = -x - y - 5*z
+    ans = optimum, argmax = lp(max, objective, constraints)
+    assert ans == lpmax(objective, constraints)
+    assert objective.subs(argmax) == optimum
+    for constr in constraints:
+        assert constr.subs(argmax) == True
+
+    r1 = x - y + 2*z <= -4
+    r2 = -x + 2*y - 3*z <= 8
+    r3 = 2*x + y - 7*z <= 10
+    constraints = [r1, r2, r3, x >= 0, y >= 0, z >= 0]
+    const = 2
+    objective = -x-y-5*z+const # has constant term
+    ans = optimum, argmax = lp(max, objective, constraints)
+    assert ans == lpmax(objective, constraints)
+    assert objective.subs(argmax) == optimum
+    for constr in constraints:
+        assert constr.subs(argmax) == True
+
+    # Section 4 Problem 1 from
+    # http://web.tecnico.ulisboa.pt/mcasquilho/acad/or/ftp/FergusonUCLA_LP.pdf
+    # answer on page 55
+    v = x1, x2, x3, x4 = symbols('x1 x2 x3 x4')
+    r1 = x1 - x2 - 2*x3 - x4 <= 4
+    r2 = 2*x1 + x3 -4*x4 <= 2
+    r3 = -2*x1 + x2 + x4 <= 1
+    objective, constraints = x1 - 2*x2 - 3*x3 - x4, [r1, r2, r3] + [
+        i >= 0 for i in v]
+    ans = optimum, argmax = lp(max, objective, constraints)
+    assert ans == lpmax(objective, constraints)
+    assert ans == (4, {x1: 7, x2: 0, x3: 0, x4: 3})
+
+    # input contains Floats
+    r1 = x - y + 2.0*z <= -4
+    r2 = -x + 2*y - 3.0*z <= 8
+    r3 = 2*x + y - 7*z <= 10
+    constraints = [r1, r2, r3] + [i >= 0 for i in (x, y, z)]
+    objective = -x-y-5*z
+    optimum, argmax = lp(max, objective, constraints)
+    assert objective.subs(argmax) == optimum
+    for constr in constraints:
+        assert constr.subs(argmax) == True
+
+    # input contains non-float or non-Rational
+    r1 = x - y + sqrt(2) * z <= -4
+    r2 = -x + 2*y - 3*z <= 8
+    r3 = 2*x + y - 7*z <= 10
+    raises(TypeError, lambda: lp(max, -x-y-5*z, [r1, r2, r3]))
+
+    r1 = x >= 0
+    raises(UnboundedLPError, lambda: lp(max, x, [r1]))
+    r2 = x <= -1
+    raises(InfeasibleLPError, lambda: lp(max, x, [r1, r2]))
+
+    # strict inequalities are not allowed
+    r1 = x > 0
+    raises(TypeError, lambda: lp(max, x, [r1]))
+
+    # not equals not allowed
+    r1 = Ne(x, 0)
+    raises(TypeError, lambda: lp(max, x, [r1]))
+
+    def make_random_problem(nvar=2, num_constraints=2, sparsity=.1):
+        def rand():
+            if random() < sparsity:
+                return sympify(0)
+            int1, int2 = [randprime(0, 200) for _ in range(2)]
+            return Rational(int1, int2)*choice([-1, 1])
+        variables = symbols('x1:%s' % (nvar + 1))
+        constraints = [(sum(rand()*x for x in variables) <= rand())
+                       for _ in range(num_constraints)]
+        objective = sum(rand() * x for x in variables)
+        return objective, constraints, variables
+
+    # equality
+    r1 = Eq(x, y)
+    r2 = Eq(y, z)
+    r3 = z <= 3
+    constraints = [r1, r2, r3]
+    objective = x
+    ans = optimum, argmax = lp(max, objective, constraints)
+    assert ans == lpmax(objective, constraints)
+    assert objective.subs(argmax) == optimum
+    for constr in constraints:
+        assert constr.subs(argmax) == True
+
+
+def test_simplex():
+    L = [
+        [[1, 1], [-1, 1], [0, 1], [-1, 0]],
+        [5, 1, 2, -1],
+        [[1, 1]],
+        [-1]]
+    A, B, C, D = _abcd(_m(*L), list=False)
+    assert _simplex(A, B, -C, -D) == (-6, [3, 2], [1, 0, 0, 0])
+    assert _simplex(A, B, -C, -D, dual=True) == (-6,
+        [1, 0, 0, 0], [5, 0])
+
+    assert _simplex([[]],[],[[1]],[0]) == (0, [0], [])
+
+    # handling of Eq (or Eq-like x<=y, x>=y conditions)
+    assert lpmax(x - y, [x <= y + 2, x >= y + 2, x >= 0, y >= 0]
+        ) == (2, {x: 2, y: 0})
+    assert lpmax(x - y, [x <= y + 2, Eq(x, y + 2), x >= 0, y >= 0]
+        ) == (2, {x: 2, y: 0})
+    assert lpmax(x - y, [x <= y + 2, Eq(x, 2)]) == (2, {x: 2, y: 0})
+    assert lpmax(y, [Eq(y, 2)]) == (2, {y: 2})
+
+    # the conditions are equivalent to Eq(x, y + 2)
+    assert lpmin(y, [x <= y + 2, x >= y + 2, y >= 0]
+        ) == (0, {x: 2, y: 0})
+    # equivalent to Eq(y, -2)
+    assert lpmax(y, [0 <= y + 2, 0 >= y + 2]) == (-2, {y: -2})
+    assert lpmax(y, [0 <= y + 2, 0 >= y + 2, y <= 0]
+        ) == (-2, {y: -2})
+
+    # extra symbols symbols
+    assert lpmin(x, [y >= 1, x >= y]) == (1, {x: 1, y: 1})
+    assert lpmin(x, [y >= 1, x >= y + z, x >= 0, z >= 0]
+        ) == (1, {x: 1, y: 1, z: 0})
+
+    # detect oscillation
+    # o1
+    v = x1, x2, x3, x4 = symbols('x1 x2 x3 x4')
+    raises(InfeasibleLPError, lambda: lpmin(
+        9*x2 - 8*x3 + 3*x4 + 6,
+        [5*x2 - 2*x3 <= 0,
+        -x1 - 8*x2 + 9*x3 <= -3,
+        10*x1 - x2+ 9*x4 <= -4] + [i >= 0 for i in v]))
+    # o2 - equations fed to lpmin are changed into a matrix
+    # system that doesn't oscillate and has the same solution
+    # as below
+    M = linear_eq_to_matrix
+    f = 5*x2 + x3 + 4*x4 - x1
+    L = 5*x2 + 2*x3 + 5*x4 - (x1 + 5)
+    cond = [L <= 0] + [Eq(3*x2 + x4, 2), Eq(-x1 + x3 + 2*x4, 1)]
+    c, d = M(f, v)
+    a, b = M(L, v)
+    aeq, beq = M(cond[1:], v)
+    ans = (S(9)/2, [0, S(1)/2, 0, S(1)/2])
+    assert linprog(c, a, b, aeq, beq, bounds=(0, 1)) == ans
+    lpans = lpmin(f, cond + [x1 >= 0, x1 <= 1,
+        x2 >= 0, x2 <= 1, x3 >= 0, x3 <= 1, x4 >= 0, x4 <= 1])
+    assert (lpans[0], list(lpans[1].values())) == ans
+
+
+def test_lpmin_lpmax():
+    v = x1, x2, y1, y2 = symbols('x1 x2 y1 y2')
+    L = [[1, -1]], [1], [[1, 1]], [2]
+    a, b, c, d = [Matrix(i) for i in L]
+    m = Matrix([[a, b], [c, d]])
+    f, constr = _primal_dual(m)[0]
+    ans = lpmin(f, constr + [i >= 0 for i in v[:2]])
+    assert ans == (-1, {x1: 1, x2: 0}),ans
+
+    L = [[1, -1], [1, 1]], [1, 1], [[1, 1]], [2]
+    a, b, c, d = [Matrix(i) for i in L]
+    m = Matrix([[a, b], [c, d]])
+    f, constr = _primal_dual(m)[1]
+    ans = lpmax(f, constr + [i >= 0 for i in v[-2:]])
+    assert ans == (-1, {y1: 1, y2: 0})
+
+
+def test_linprog():
+    for do in range(2):
+        if not do:
+            M = lambda a, b: linear_eq_to_matrix(a, b)
+        else:
+            # check matrices as list
+            M = lambda a, b: tuple([
+                i.tolist() for i in linear_eq_to_matrix(a, b)])
+
+        v = x, y, z = symbols('x1:4')
+        f = x + y - 2*z
+        c = M(f, v)[0]
+        ineq = [7*x + 4*y - 7*z <= 3,
+            3*x - y + 10*z <= 6,
+            x >= 0, y >= 0, z >= 0]
+        ab = M([i.lts - i.gts for i in ineq], v)
+        ans = (-S(6)/5, [0, 0, S(3)/5])
+        assert lpmin(f, ineq) == (ans[0], dict(zip(v, ans[1])))
+        assert linprog(c, *ab) == ans
+
+        f += 1
+        c = M(f, v)[0]
+        eq = [Eq(y - 9*x, 1)]
+        abeq = M([i.lhs - i.rhs for i in eq], v)
+        ans = (1 - S(2)/5, [0, 1, S(7)/10])
+        assert lpmin(f, ineq + eq) == (ans[0], dict(zip(v, ans[1])))
+        assert linprog(c, *ab, *abeq) == (ans[0] - 1, ans[1])
+
+        eq = [z - y <= S.Half]
+        abeq = M([i.lhs - i.rhs for i in eq], v)
+        ans = (1 - S(10)/9, [0, S(1)/9, S(11)/18])
+        assert lpmin(f, ineq + eq) == (ans[0], dict(zip(v, ans[1])))
+        assert linprog(c, *ab, *abeq) == (ans[0] - 1, ans[1])
+
+        bounds = [(0, None), (0, None), (None, S.Half)]
+        ans = (0, [0, 0, S.Half])
+        assert lpmin(f, ineq + [z <= S.Half]) == (
+            ans[0], dict(zip(v, ans[1])))
+        assert linprog(c, *ab, bounds=bounds) == (ans[0] - 1, ans[1])
+        assert linprog(c, *ab, bounds={v.index(z): bounds[-1]}
+            ) == (ans[0] - 1, ans[1])
+        eq = [z - y <= S.Half]
+
+    assert linprog([[1]], [], [], bounds=(2, 3)) == (2, [2])
+    assert linprog([1], [], [], bounds=(2, 3)) == (2, [2])
+    assert linprog([1], bounds=(2, 3)) == (2, [2])
+    assert linprog([1, -1], [[1, 1]], [2], bounds={1:(None, None)}
+        ) == (-2, [0, 2])
+    assert linprog([1, -1], [[1, 1]], [5], bounds={1:(3, None)}
+        ) == (-5, [0, 5])