def test_piecewise_fold():
p = Piecewise((x, x < 1), (1, 1 <= x))
assert piecewise_fold(x * p) == Piecewise((x**2, x < 1), (x, 1 <= x))
assert piecewise_fold(p + p) == Piecewise((2 * x, x < 1), (2, 1 <= x))
assert piecewise_fold(Piecewise((1, x < 0), (2, True))
+ Piecewise((10, x < 0), (-10, True))) == \
Piecewise((11, x < 0), (-8, True))
p1 = Piecewise((0, x < 0), (x, x <= 1), (0, True))
p2 = Piecewise((0, x < 0), (1 - x, x <= 1), (0, True))
p = 4 * p1 + 2 * p2
assert integrate(piecewise_fold(p),
(x, -oo, oo)) == integrate(2 * x + 2, (x, 0, 1))
assert piecewise_fold(
Piecewise((1, y <= 0), (-Piecewise((2, y >= 0)), True))) == Piecewise(
(1, y <= 0), (-2, y >= 0))
assert piecewise_fold(Piecewise(
(x, ITE(x > 0, y < 1, y > 1)))) == Piecewise(
(x, ((x <= 0) | (y < 1)) & ((x > 0) | (y > 1))))
a, b = (Piecewise((2, Eq(x, 0)), (0, True)),
Piecewise((x, Eq(-x + y, 0)), (1, Eq(-x + y, 1)), (0, True)))
assert piecewise_fold(Mul(a, b, evaluate=False)) == piecewise_fold(
Mul(b, a, evaluate=False))
def test_count_ops_non_visual():
def count(val):
return count_ops(val, visual=False)
assert count(x) == 0
assert count(x) is not S.Zero
assert count(x + y) == 1
assert count(x + y) is not S.One
assert count(x + y*x + 2*y) == 4
assert count({x + y: x}) == 1
assert count({x + y: S(2) + x}) is not S.One
assert count(Or(x,y)) == 1
assert count(And(x,y)) == 1
assert count(Not(x)) == 0
assert count(Nor(x,y)) == 1
assert count(Nand(x,y)) == 1
assert count(Xor(x,y)) == 3
assert count(Implies(x,y)) == 1
assert count(Equivalent(x,y)) == 1
assert count(ITE(x,y,z)) == 3
assert count(ITE(True,x,y)) == 0
def test_ITE():
A, B, C = map(Boolean, symbols('A,B,C'))
assert ITE(True, False, True) == False
assert ITE(True, True, False) == True
assert ITE(False, True, False) == False
assert ITE(False, False, True) == True
A = True
assert ITE(A, B, C) == B
A = False
assert ITE(A, B, C) == C
B = True
assert ITE(And(A, B), B, C) == C
assert ITE(Or(A, False), And(B, True), False) == False
def test_ITE():
assert lambdify((x, y, z), ITE(x, y, z))(True, 5, 3) == 5
assert lambdify((x, y, z), ITE(x, y, z))(False, 5, 3) == 3
def test_conditions_as_alternate_booleans():
a, b, c = symbols('a:c')
assert Piecewise((x, Piecewise((y < 1, x > 0),
(y > 1, True)))) == Piecewise(
(x, ITE(x > 0, y < 1, y > 1)))
def test_piecewise():
# Test canonicalization
assert Piecewise((x, x < 1), (0, True)) == Piecewise((x, x < 1), (0, True))
assert Piecewise((x, x < 1), (0, True), (1, True)) == \
Piecewise((x, x < 1), (0, True))
assert Piecewise((x, x < 1), (0, False), (-1, 1 > 2)) == \
Piecewise((x, x < 1))
assert Piecewise((x, x < 1), (0, x < 1), (0, True)) == \
Piecewise((x, x < 1), (0, True))
assert Piecewise((x, x < 1), (0, x < 2), (0, True)) == \
Piecewise((x, x < 1), (0, True))
assert Piecewise((x, x < 1), (x, x < 2), (0, True)) == \
Piecewise((x, Or(x < 1, x < 2)), (0, True))
assert Piecewise((x, x < 1), (x, x < 2), (x, True)) == x
assert Piecewise((x, True)) == x
# False condition is never retained
assert Piecewise((x, False)) == Piecewise(
(x, False), evaluate=False) == Piecewise()
raises(TypeError, lambda: Piecewise(x))
assert Piecewise((x, 1)) == x # 1 and 0 are accepted as True/False
raises(TypeError, lambda: Piecewise((x, 2)))
raises(TypeError, lambda: Piecewise((x, x**2)))
raises(TypeError, lambda: Piecewise(([1], True)))
assert Piecewise(((1, 2), True)) == Tuple(1, 2)
cond = (Piecewise((1, x < 0), (2, True)) < y)
assert Piecewise((1, cond)) == Piecewise((1, ITE(x < 0, y > 1, y > 2)))
assert Piecewise((1, x > 0), (2, And(x <= 0, x > -1))) == Piecewise(
(1, x > 0), (2, x > -1))
# Test subs
p = Piecewise((-1, x < -1), (x**2, x < 0), (log(x), x >= 0))
p_x2 = Piecewise((-1, x**2 < -1), (x**4, x**2 < 0), (log(x**2), x**2 >= 0))
assert p.subs(x, x**2) == p_x2
assert p.subs(x, -5) == -1
assert p.subs(x, -1) == 1
assert p.subs(x, 1) == log(1)
# More subs tests
p2 = Piecewise((1, x < pi), (-1, x < 2 * pi), (0, x > 2 * pi))
p3 = Piecewise((1, Eq(x, 0)), (1 / x, True))
p4 = Piecewise((1, Eq(x, 0)), (2, 1 / x > 2))
assert p2.subs(x, 2) == 1
assert p2.subs(x, 4) == -1
assert p2.subs(x, 10) == 0
assert p3.subs(x, 0.0) == 1
assert p4.subs(x, 0.0) == 1
f, g, h = symbols('f,g,h', cls=Function)
pf = Piecewise((f(x), x < -1), (f(x) + h(x) + 2, x <= 1))
pg = Piecewise((g(x), x < -1), (g(x) + h(x) + 2, x <= 1))
assert pg.subs(g, f) == pf
assert Piecewise((1, Eq(x, 0)), (0, True)).subs(x, 0) == 1
assert Piecewise((1, Eq(x, 0)), (0, True)).subs(x, 1) == 0
assert Piecewise((1, Eq(x, y)), (0, True)).subs(x, y) == 1
assert Piecewise((1, Eq(x, z)), (0, True)).subs(x, z) == 1
assert Piecewise((1, Eq(exp(x), cos(z))), (0, True)).subs(x, z) == \
Piecewise((1, Eq(exp(z), cos(z))), (0, True))
p5 = Piecewise((0, Eq(cos(x) + y, 0)), (1, True))
assert p5.subs(y, 0) == Piecewise((0, Eq(cos(x), 0)), (1, True))
assert Piecewise((-1, y < 1), (0, x < 0), (1, Eq(x, 0)),
(2, True)).subs(x, 1) == Piecewise((-1, y < 1), (2, True))
assert Piecewise((1, Eq(x**2, -1)), (2, x < 0)).subs(x, I) == 1
# Test evalf
assert p.evalf() == p
assert p.evalf(subs={x: -2}) == -1
assert p.evalf(subs={x: -1}) == 1
assert p.evalf(subs={x: 1}) == log(1)
# Test doit
f_int = Piecewise((Integral(x, (x, 0, 1)), x < 1))
assert f_int.doit() == Piecewise((1 / 2, x < 1))
# Test differentiation
f = x
fp = x * p
dp = Piecewise((0, x < -1), (2 * x, x < 0), (1 / x, x >= 0))
fp_dx = x * dp + p
assert diff(p, x) == dp
assert diff(f * p, x) == fp_dx
# Test simple arithmetic
assert x * p == fp
assert x * p + p == p + x * p
assert p + f == f + p
assert p + dp == dp + p
assert p - dp == -(dp - p)
# Test power
dp2 = Piecewise((0, x < -1), (4 * x**2, x < 0), (1 / x**2, x >= 0))
assert dp**2 == dp2
# Test _eval_interval
f1 = x * y + 2
f2 = x * y**2 + 3
peval = Piecewise((f1, x < 0), (f2, x > 0))
peval_interval = f1.subs(x, 0) - f1.subs(x, -1) + f2.subs(x, 1) - f2.subs(
x, 0)
assert peval._eval_interval(x, 0, 0) == 0
assert peval._eval_interval(x, -1, 1) == peval_interval
peval2 = Piecewise((f1, x < 0), (f2, True))
assert peval2._eval_interval(x, 0, 0) == 0
assert peval2._eval_interval(x, 1, -1) == -peval_interval
assert peval2._eval_interval(x, -1, -2) == f1.subs(x, -2) - f1.subs(x, -1)
assert peval2._eval_interval(x, -1, 1) == peval_interval
assert peval2._eval_interval(x, None, 0) == peval2.subs(x, 0)
assert peval2._eval_interval(x, -1, None) == -peval2.subs(x, -1)
# Test integration
assert p.integrate() == Piecewise((-x, x < -1), (x**3 / 3 + 4 / 3, x < 0),
(x * log(x) - x + 4 / 3, True))
p = Piecewise((x, x < 1), (x**2, -1 <= x), (x, 3 < x))
assert integrate(p, (x, -2, 2)) == 5 / 6.0
assert integrate(p, (x, 2, -2)) == -5 / 6.0
p = Piecewise((0, x < 0), (1, x < 1), (0, x < 2), (1, x < 3), (0, True))
assert integrate(p, (x, -oo, oo)) == 2
p = Piecewise((x, x < -10), (x**2, x <= -1), (x, 1 < x))
assert integrate(p, (x, -2, 2)) == Undefined
# Test commutativity
assert isinstance(p, Piecewise) and p.is_commutative is True
def test_Piecewise_rewrite_as_ITE():
a, b, c, d = symbols('a:d')
def _ITE(*args):
return Piecewise(*args).rewrite(ITE)
assert _ITE((a, x < 1), (b, x >= 1)) == ITE(x < 1, a, b)
assert _ITE((a, x < 1), (b, x < oo)) == ITE(x < 1, a, b)
assert _ITE((a, x < 1), (b, Or(y < 1, x < oo)),
(c, y > 0)) == ITE(x < 1, a, b)
assert _ITE((a, x < 1), (b, True)) == ITE(x < 1, a, b)
assert _ITE((a, x < 1), (b, x < 2),
(c, True)) == ITE(x < 1, a, ITE(x < 2, b, c))
assert _ITE((a, x < 1), (b, y < 2),
(c, True)) == ITE(x < 1, a, ITE(y < 2, b, c))
assert _ITE((a, x < 1), (b, x < oo), (c, y < 1)) == ITE(x < 1, a, b)
assert _ITE((a, x < 1), (c, y < 1), (b, x < oo),
(d, True)) == ITE(x < 1, a, ITE(y < 1, c, b))
assert _ITE((a, x < 0), (b, Or(x < oo, y < 1))) == ITE(x < 0, a, b)
raises(TypeError, lambda: _ITE((x + 1, x < 1), (x, True)))
# if `a` in the following were replaced with y then the coverage
# is complete but something other than as_set would need to be
# used to detect this
raises(NotImplementedError, lambda: _ITE((x, x < y), (y, x >= a)))
raises(ValueError, lambda: _ITE((a, x < 2), (b, x > 3)))
def test_count_ops_visual():
ADD, MUL, POW, SIN, COS, EXP, AND, D, G, M = symbols(
'Add Mul Pow sin cos exp And Derivative Integral Sum'.upper())
DIV, SUB, NEG = symbols('DIV SUB NEG')
LT, LE, GT, GE, EQ, NE = symbols('LT LE GT GE EQ NE')
NOT, OR, AND, XOR, IMPLIES, EQUIVALENT, _ITE, BASIC, TUPLE = symbols(
'Not Or And Xor Implies Equivalent ITE Basic Tuple'.upper())
def count(val):
return count_ops(val, visual=True)
assert count(7) is S.Zero
assert count(S(7)) is S.Zero
assert count(-1) == NEG
assert count(-2) == NEG
assert count(S(2) / 3) == DIV
assert count(Rational(2, 3)) == DIV
assert count(pi / 3) == DIV
assert count(-pi / 3) == DIV + NEG
assert count(I - 1) == SUB
assert count(1 - I) == SUB
assert count(1 - 2 * I) == SUB + MUL
assert count(x) is S.Zero
assert count(-x) == NEG
assert count(-2 * x / 3) == NEG + DIV + MUL
assert count(Rational(-2, 3) * x) == NEG + DIV + MUL
assert count(1 / x) == DIV
assert count(1 / (x * y)) == DIV + MUL
assert count(-1 / x) == NEG + DIV
assert count(-2 / x) == NEG + DIV
assert count(x / y) == DIV
assert count(-x / y) == NEG + DIV
assert count(x**2) == POW
assert count(-x**2) == POW + NEG
assert count(-2 * x**2) == POW + MUL + NEG
assert count(x + pi / 3) == ADD + DIV
assert count(x + S.One / 3) == ADD + DIV
assert count(x + Rational(1, 3)) == ADD + DIV
assert count(x + y) == ADD
assert count(x - y) == SUB
assert count(y - x) == SUB
assert count(-1 / (x - y)) == DIV + NEG + SUB
assert count(-1 / (y - x)) == DIV + NEG + SUB
assert count(1 + x**y) == ADD + POW
assert count(1 + x + y) == 2 * ADD
assert count(1 + x + y + z) == 3 * ADD
assert count(1 + x**y + 2 * x * y + y**2) == 3 * ADD + 2 * POW + 2 * MUL
assert count(2 * z + y + x + 1) == 3 * ADD + MUL
assert count(2 * z + y**17 + x + 1) == 3 * ADD + MUL + POW
assert count(2 * z + y**17 + x + sin(x)) == 3 * ADD + POW + MUL + SIN
assert count(2 * z + y**17 + x +
sin(x**2)) == 3 * ADD + MUL + 2 * POW + SIN
assert count(2 * z + y**17 + x + sin(x**2) +
exp(cos(x))) == 4 * ADD + MUL + 2 * POW + EXP + COS + SIN
assert count(Derivative(x, x)) == D
assert count(Integral(x, x) + 2 * x / (1 + x)) == G + DIV + MUL + 2 * ADD
assert count(Sum(x, (x, 1, x + 1)) + 2 * x /
(1 + x)) == M + DIV + MUL + 3 * ADD
assert count(Basic()) is S.Zero
assert count({x + 1: sin(x)}) == ADD + SIN
assert count([x + 1, sin(x) + y, None]) == ADD + SIN + ADD
assert count({x + 1: sin(x), y: cos(x) + 1}) == SIN + COS + 2 * ADD
assert count({}) is S.Zero
assert count([x + 1, sin(x) * y, None]) == SIN + ADD + MUL
assert count([]) is S.Zero
assert count(Basic()) == 0
assert count(Basic(Basic(), Basic(x, x + y))) == ADD + 2 * BASIC
assert count(Basic(x, x + y)) == ADD + BASIC
assert [count(Rel(x, y, op)) for op in '< <= > >= == <> !='.split()
] == [LT, LE, GT, GE, EQ, NE, NE]
assert count(Or(x, y)) == OR
assert count(And(x, y)) == AND
assert count(Or(x, Or(y, And(z, a)))) == AND + OR
assert count(Nor(x, y)) == NOT + OR
assert count(Nand(x, y)) == NOT + AND
assert count(Xor(x, y)) == XOR
assert count(Implies(x, y)) == IMPLIES
assert count(Equivalent(x, y)) == EQUIVALENT
assert count(ITE(x, y, z)) == _ITE
assert count([Or(x, y), And(x, y), Basic(x + y)]) == ADD + AND + BASIC + OR
assert count(Basic(Tuple(x))) == BASIC + TUPLE
#It checks that TUPLE is counted as an operation.
assert count(Eq(x + y, S(2))) == ADD + EQ
def test_count_ops_visual():
ADD, MUL, POW, SIN, COS, EXP, AND, D, G = symbols(
'Add Mul Pow sin cos exp And Derivative Integral'.upper())
DIV, SUB, NEG = symbols('DIV SUB NEG')
OR, AND, IMPLIES, EQUIVALENT, BASIC, TUPLE = symbols(
'Or And Implies Equivalent Basic Tuple'.upper())
def count(val):
return count_ops(val, visual=True)
assert count(7) is S.Zero
assert count(S(7)) is S.Zero
assert count(-1) == NEG
assert count(-2) == NEG
assert count(S(2)/3) == DIV
assert count(pi/3) == DIV
assert count(-pi/3) == DIV + NEG
assert count(I - 1) == SUB
assert count(1 - I) == SUB
assert count(1 - 2*I) == SUB + MUL
assert count(x) is S.Zero
assert count(-x) == NEG
assert count(-2*x/3) == NEG + DIV + MUL
assert count(1/x) == DIV
assert count(1/(x*y)) == DIV + MUL
assert count(-1/x) == NEG + DIV
assert count(-2/x) == NEG + DIV
assert count(x/y) == DIV
assert count(-x/y) == NEG + DIV
assert count(x**2) == POW
assert count(-x**2) == POW + NEG
assert count(-2*x**2) == POW + MUL + NEG
assert count(x + pi/3) == ADD + DIV
assert count(x + S(1)/3) == ADD + DIV
assert count(x + y) == ADD
assert count(x - y) == SUB
assert count(y - x) == SUB
assert count(-1/(x - y)) == DIV + NEG + SUB
assert count(-1/(y - x)) == DIV + NEG + SUB
assert count(1 + x**y) == ADD + POW
assert count(1 + x + y) == 2*ADD
assert count(1 + x + y + z) == 3*ADD
assert count(1 + x**y + 2*x*y + y**2) == 3*ADD + 2*POW + 2*MUL
assert count(2*z + y + x + 1) == 3*ADD + MUL
assert count(2*z + y**17 + x + 1) == 3*ADD + MUL + POW
assert count(2*z + y**17 + x + sin(x)) == 3*ADD + POW + MUL + SIN
assert count(2*z + y**17 + x + sin(x**2)) == 3*ADD + MUL + 2*POW + SIN
assert count(2*z + y**17 + x + sin(
x**2) + exp(cos(x))) == 4*ADD + MUL + 2*POW + EXP + COS + SIN
assert count(Derivative(x, x)) == D
assert count(Integral(x, x) + 2*x/(1 + x)) == G + DIV + MUL + 2*ADD
assert count(Basic()) is S.Zero
assert count({x + 1: sin(x)}) == ADD + SIN
assert count([x + 1, sin(x) + y, None]) == ADD + SIN + ADD
assert count({x + 1: sin(x), y: cos(x) + 1}) == SIN + COS + 2*ADD
assert count({}) is S.Zero
assert count([x + 1, sin(x)*y, None]) == SIN + ADD + MUL
assert count([]) is S.Zero
assert count(Basic()) == 0
assert count(Basic(Basic(),Basic(x,x+y))) == ADD + 2*BASIC
assert count(Basic(x, x + y)) == ADD + BASIC
assert count(Or(x,y)) == OR
assert count(And(x,y)) == AND
assert count(And(x**y,z)) == AND + POW
assert count(Or(x,Or(y,And(z,a)))) == AND + 2*OR
assert count(Nor(x,y)) == AND
assert count(Nand(x,y)) == OR
assert count(Xor(x,y)) == 2*AND + OR
assert count(Implies(x,y)) == IMPLIES
assert count(Equivalent(x,y)) == EQUIVALENT
assert count(ITE(x,y,z)) == 2*AND + OR
assert count([Or(x,y), And(x,y), Basic(x+y)]) == ADD + AND + BASIC + OR
assert count(Basic(Tuple(x))) == BASIC + TUPLE
#It checks that TUPLE is counted as an operation.
assert count(Eq(x + y, S(2))) == ADD
