def test_Max():
from sympy.abc import x, y, z
n = Symbol('n', negative=True)
n_ = Symbol('n_', negative=True)
nn = Symbol('nn', nonnegative=True)
nn_ = Symbol('nn_', nonnegative=True)
p = Symbol('p', positive=True)
p_ = Symbol('p_', positive=True)
np = Symbol('np', nonpositive=True)
np_ = Symbol('np_', nonpositive=True)
r = Symbol('r', real=True)
assert Max(5, 4) == 5
# lists
raises(ValueError, lambda: Max())
assert Max(x, y) == Max(y, x)
assert Max(x, y, z) == Max(z, y, x)
assert Max(x, Max(y, z)) == Max(z, y, x)
assert Max(x, Min(y, oo)) == Max(x, y)
assert Max(n, -oo, n_, p, 2) == Max(p, 2)
assert Max(n, -oo, n_, p) == p
assert Max(2, x, p, n, -oo, S.NegativeInfinity, n_, p, 2) == Max(2, x, p)
assert Max(0, x, 1, y) == Max(1, x, y)
assert Max(r, r + 1, r - 1) == 1 + r
assert Max(1000, 100, -100, x, p, n) == Max(p, x, 1000)
assert Max(cos(x), sin(x)) == Max(sin(x), cos(x))
assert Max(cos(x), sin(x)).subs(x, 1) == sin(1)
assert Max(cos(x), sin(x)).subs(x, S(1)/2) == cos(S(1)/2)
raises(ValueError, lambda: Max(cos(x), sin(x)).subs(x, I))
raises(ValueError, lambda: Max(I))
raises(ValueError, lambda: Max(I, x))
raises(ValueError, lambda: Max(S.ComplexInfinity, 1))
# interesting:
# Max(n, -oo, n_, p, 2) == Max(p, 2)
# True
# Max(n, -oo, n_, p, 1000) == Max(p, 1000)
# False
assert Max(1, x).diff(x) == Heaviside(x - 1)
assert Max(x, 1).diff(x) == Heaviside(x - 1)
assert Max(x**2, 1 + x, 1).diff(x) == \
2*x*Heaviside(x**2 - Max(1, x + 1)) \
+ Heaviside(x - Max(1, x**2) + 1)
a, b = Symbol('a', real=True), Symbol('b', real=True)
# a and b are both real, Max(a, b) should be real
assert Max(a, b).is_real
# issue 7233
e = Max(0, x)
assert e.evalf == e.n
assert e.n().args == (0, x)
def __rdiv__(self, other):
if isinstance(other, Expr):
if other.is_real:
if other.is_zero:
return S.Zero
if S.Zero in self:
if self.min == S.Zero:
if other.is_positive:
return AccumBounds(Mul(other, 1 / self.max), oo)
if other.is_negative:
return AccumBounds(-oo, Mul(other, 1 / self.max))
if self.max == S.Zero:
if other.is_positive:
return AccumBounds(-oo, Mul(other, 1 / self.min))
if other.is_negative:
return AccumBounds(Mul(other, 1 / self.min), oo)
return AccumBounds(-oo, oo)
else:
return AccumBounds(Min(other / self.min, other / self.max),
Max(other / self.min, other / self.max))
return Mul(other, 1 / self, evaluate=False)
else:
return NotImplemented
def __mul__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
return AccumBounds(
Min(Mul(self.min, other.min), Mul(self.min, other.max),
Mul(self.max, other.min), Mul(self.max, other.max)),
Max(Mul(self.min, other.min), Mul(self.min, other.max),
Mul(self.max, other.min), Mul(self.max, other.max)))
if other is S.Infinity:
if self.min.is_zero:
return AccumBounds(0, oo)
if self.max.is_zero:
return AccumBounds(-oo, 0)
if other is S.NegativeInfinity:
if self.min.is_zero:
return AccumBounds(-oo, 0)
if self.max.is_zero:
return AccumBounds(0, oo)
if other.is_real:
if other.is_zero:
if self == AccumBounds(-oo, oo):
return AccumBounds(-oo, oo)
if self.max is S.Infinity:
return AccumBounds(0, oo)
if self.min is S.NegativeInfinity:
return AccumBounds(-oo, 0)
return S.Zero
if other.is_positive:
return AccumBounds(Mul(self.min, other),
Mul(self.max, other))
elif other.is_negative:
return AccumBounds(Mul(self.max, other),
Mul(self.min, other))
if isinstance(other, Order):
return other
return Mul(self, other, evaluate=False)
return NotImplemented
def major(self):
"""Longer axis of the ellipse (if it can be determined) else hradius.
Returns
=======
major : number or expression
See Also
========
hradius, vradius, minor
Examples
========
>>> from sympy import Point, Ellipse, Symbol
>>> p1 = Point(0, 0)
>>> e1 = Ellipse(p1, 3, 1)
>>> e1.major
3
>>> a = Symbol('a')
>>> b = Symbol('b')
>>> Ellipse(p1, a, b).major
a
>>> Ellipse(p1, b, a).major
b
>>> m = Symbol('m')
>>> M = m + 1
>>> Ellipse(p1, m, M).major
m + 1
"""
rv = Max(*self[1:3])
if rv.func is Max:
return self.hradius
return rv
def __rtruediv__(self, other):
if isinstance(other, Expr):
if other.is_extended_real:
if other.is_zero:
return S.Zero
if (self.min.is_extended_nonpositive
and self.max.is_extended_nonnegative):
if self.min.is_zero:
if other.is_extended_positive:
return AccumBounds(Mul(other, 1 / self.max), oo)
if other.is_extended_negative:
return AccumBounds(-oo, Mul(other, 1 / self.max))
if self.max.is_zero:
if other.is_extended_positive:
return AccumBounds(-oo, Mul(other, 1 / self.min))
if other.is_extended_negative:
return AccumBounds(Mul(other, 1 / self.min), oo)
return AccumBounds(-oo, oo)
else:
return AccumBounds(Min(other / self.min, other / self.max),
Max(other / self.min, other / self.max))
return Mul(other, 1 / self, evaluate=False)
else:
return NotImplemented
def compute_a_n(prob_fun, alpha=0):
P = prob_fun
t = Symbol('t0', positive=True)
a_n = Symbol('a_n', positive=True)
a_n_integral = Integral(
((1 + alpha) - (1 - alpha) * P(t)) * f_star(P, t, []), (t, a_n, 1))
a_n_integrated = a_n_integral.doit()
P_a_n_solutions = solve(a_n_integrated - 2 * (1 - alpha), P(a_n))
P_a_n = Max(*P_a_n_solutions)
print("P(a_n) = %s" % P_a_n)
a_n_solutions = solve(P(a_n) - P_a_n, a_n)
a_n_solutions_in_range = [soln for soln in a_n_solutions if 0 < soln <= 1]
assert len(a_n_solutions_in_range) == 1
a_n = a_n_solutions_in_range[0]
print("a_n = %s" % a_n)
h_n_integral = Integral(f_star(P, t, []), (t, a_n, 1))
h_n_integrated = h_n_integral.doit()
h_n = (1 - alpha) / h_n_integrated
print("h_n = %s" % h_n)
return (a_n, h_n)
def test_Min():
from sympy.abc import x, y, z
n = Symbol('n', negative=True)
n_ = Symbol('n_', negative=True)
nn = Symbol('nn', nonnegative=True)
nn_ = Symbol('nn_', nonnegative=True)
p = Symbol('p', positive=True)
p_ = Symbol('p_', positive=True)
np = Symbol('np', nonpositive=True)
np_ = Symbol('np_', nonpositive=True)
r = Symbol('r', real=True)
assert Min(5, 4) == 4
assert Min(-oo, -oo) == -oo
assert Min(-oo, n) == -oo
assert Min(n, -oo) == -oo
assert Min(-oo, np) == -oo
assert Min(np, -oo) == -oo
assert Min(-oo, 0) == -oo
assert Min(0, -oo) == -oo
assert Min(-oo, nn) == -oo
assert Min(nn, -oo) == -oo
assert Min(-oo, p) == -oo
assert Min(p, -oo) == -oo
assert Min(-oo, oo) == -oo
assert Min(oo, -oo) == -oo
assert Min(n, n) == n
assert Min(n, np) == Min(n, np)
assert Min(np, n) == Min(np, n)
assert Min(n, 0) == n
assert Min(0, n) == n
assert Min(n, nn) == n
assert Min(nn, n) == n
assert Min(n, p) == n
assert Min(p, n) == n
assert Min(n, oo) == n
assert Min(oo, n) == n
assert Min(np, np) == np
assert Min(np, 0) == np
assert Min(0, np) == np
assert Min(np, nn) == np
assert Min(nn, np) == np
assert Min(np, p) == np
assert Min(p, np) == np
assert Min(np, oo) == np
assert Min(oo, np) == np
assert Min(0, 0) == 0
assert Min(0, nn) == 0
assert Min(nn, 0) == 0
assert Min(0, p) == 0
assert Min(p, 0) == 0
assert Min(0, oo) == 0
assert Min(oo, 0) == 0
assert Min(nn, nn) == nn
assert Min(nn, p) == Min(nn, p)
assert Min(p, nn) == Min(p, nn)
assert Min(nn, oo) == nn
assert Min(oo, nn) == nn
assert Min(p, p) == p
assert Min(p, oo) == p
assert Min(oo, p) == p
assert Min(oo, oo) == oo
assert Min(n, n_).func is Min
assert Min(nn, nn_).func is Min
assert Min(np, np_).func is Min
assert Min(p, p_).func is Min
# lists
raises(ValueError, lambda: Min())
assert Min(x, y) == Min(y, x)
assert Min(x, y, z) == Min(z, y, x)
assert Min(x, Min(y, z)) == Min(z, y, x)
assert Min(x, Max(y, -oo)) == Min(x, y)
assert Min(p, oo, n, p, p, p_) == n
assert Min(p_, n_, p) == n_
assert Min(n, oo, -7, p, p, 2) == Min(n, -7)
assert Min(2, x, p, n, oo, n_, p, 2, -2, -2) == Min(-2, x, n, n_)
assert Min(0, x, 1, y) == Min(0, x, y)
assert Min(1000, 100, -100, x, p, n) == Min(n, x, -100)
assert Min(cos(x), sin(x)) == Min(cos(x), sin(x))
assert Min(cos(x), sin(x)).subs(x, 1) == cos(1)
assert Min(cos(x), sin(x)).subs(x, S(1) / 2) == sin(S(1) / 2)
raises(ValueError, lambda: Min(cos(x), sin(x)).subs(x, I))
raises(ValueError, lambda: Min(I))
raises(ValueError, lambda: Min(I, x))
raises(ValueError, lambda: Min(S.ComplexInfinity, x))
assert Min(1, x).diff(x) == Heaviside(1 - x)
assert Min(x, 1).diff(x) == Heaviside(1 - x)
assert Min(0, -x, 1 - 2*x).diff(x) == -Heaviside(x + Min(0, -2*x + 1)) \
- 2*Heaviside(2*x + Min(0, -x) - 1)
# issue 7619
f = Function('f')
assert Min(1, 2 * Min(f(1), 2)) # doesn't fail
# issue 7233
e = Min(0, x)
assert e.evalf == e.n
assert e.n().args == (0, x)
# issue 8643
m = Min(n, p_, n_, r)
assert m.is_positive is False
assert m.is_nonnegative is False
assert m.is_negative is True
m = Min(p, p_)
assert m.is_positive is True
assert m.is_nonnegative is True
assert m.is_negative is False
m = Min(p, nn_, p_)
assert m.is_positive is None
assert m.is_nonnegative is True
assert m.is_negative is False
m = Min(nn, p, r)
assert m.is_positive is None
assert m.is_nonnegative is None
assert m.is_negative is None
def test_sympy__functions__elementary__miscellaneous__Max():
from sympy.functions.elementary.miscellaneous import Max
assert _test_args(Max(x, 2))
def test_Max():
from sympy.abc import x, y, z
n = Symbol('n', negative=True)
n_ = Symbol('n_', negative=True)
nn = Symbol('nn', nonnegative=True)
nn_ = Symbol('nn_', nonnegative=True)
p = Symbol('p', positive=True)
p_ = Symbol('p_', positive=True)
np = Symbol('np', nonpositive=True)
np_ = Symbol('np_', nonpositive=True)
r = Symbol('r', real=True)
assert Max(5, 4) == 5
# lists
raises(ValueError, lambda: Max())
assert Max(x, y) == Max(y, x)
assert Max(x, y, z) == Max(z, y, x)
assert Max(x, Max(y, z)) == Max(z, y, x)
assert Max(x, Min(y, oo)) == Max(x, y)
assert Max(n, -oo, n_, p, 2) == Max(p, 2)
assert Max(n, -oo, n_, p) == p
assert Max(2, x, p, n, -oo, S.NegativeInfinity, n_, p, 2) == Max(2, x, p)
assert Max(0, x, 1, y) == Max(1, x, y)
assert Max(r, r + 1, r - 1) == 1 + r
assert Max(1000, 100, -100, x, p, n) == Max(p, x, 1000)
assert Max(cos(x), sin(x)) == Max(sin(x), cos(x))
assert Max(cos(x), sin(x)).subs(x, 1) == sin(1)
assert Max(cos(x), sin(x)).subs(x, S(1) / 2) == cos(S(1) / 2)
raises(ValueError, lambda: Max(cos(x), sin(x)).subs(x, I))
raises(ValueError, lambda: Max(I))
raises(ValueError, lambda: Max(I, x))
raises(ValueError, lambda: Max(S.ComplexInfinity, 1))
assert Max(n, -oo, n_, p, 2) == Max(p, 2)
assert Max(n, -oo, n_, p, 1000) == Max(p, 1000)
assert Max(1, x).diff(x) == Heaviside(x - 1)
assert Max(x, 1).diff(x) == Heaviside(x - 1)
assert Max(x**2, 1 + x, 1).diff(x) == \
2*x*Heaviside(x**2 - Max(1, x + 1)) \
+ Heaviside(x - Max(1, x**2) + 1)
e = Max(0, x)
assert e.evalf == e.n
assert e.n().args == (0, x)
# issue 8643
m = Max(p, p_, n, r)
assert m.is_positive is True
assert m.is_nonnegative is True
assert m.is_negative is False
m = Max(n, n_)
assert m.is_positive is False
assert m.is_nonnegative is False
assert m.is_negative is True
m = Max(n, n_, r)
assert m.is_positive is None
assert m.is_nonnegative is None
assert m.is_negative is None
m = Max(n, nn, r)
assert m.is_positive is None
assert m.is_nonnegative is True
assert m.is_negative is False
def _sort_expr_cond(self, sym, a, b, targetcond=None):
"""Determine what intervals the expr, cond pairs affect.
1) If cond is True, then log it as default
1.1) Currently if cond can't be evaluated, throw NotImplementedError.
2) For each inequality, if previous cond defines part of the interval
update the new conds interval.
- eg x < 1, x < 3 -> [oo,1],[1,3] instead of [oo,1],[oo,3]
3) Sort the intervals to make it easier to find correct exprs
Under normal use, we return the expr,cond pairs in increasing order
along the real axis corresponding to the symbol sym. If targetcond
is given, we return a list of (lowerbound, upperbound) pairs for
this condition."""
default = None
int_expr = []
expr_cond = []
or_cond = False
or_intervals = []
for expr, cond in self.args:
if isinstance(cond, Or):
for cond2 in sorted(cond.args, key=default_sort_key):
expr_cond.append((expr, cond2))
else:
expr_cond.append((expr, cond))
if cond is True:
break
for expr, cond in expr_cond:
if cond is True:
default = expr
break
elif isinstance(cond, Equality):
continue
elif isinstance(cond, And):
lower = S.NegativeInfinity
upper = S.Infinity
for cond2 in cond.args:
if cond2.lts.has(sym):
upper = Min(cond2.gts, upper)
elif cond2.gts.has(sym):
lower = Max(cond2.lts, lower)
else:
lower, upper = cond.lts, cond.gts # part 1: initialize with givens
if cond.lts.has(sym): # part 1a: expand the side ...
lower = S.NegativeInfinity # e.g. x <= 0 ---> -oo <= 0
elif cond.gts.has(sym): # part 1a: ... that can be expanded
upper = S.Infinity # e.g. x >= 0 ---> oo >= 0
else:
raise NotImplementedError(
"Unable to handle interval evaluation of expression.")
# part 1b: Reduce (-)infinity to what was passed in.
lower, upper = Max(a, lower), Min(b, upper)
for n in xrange(len(int_expr)):
# Part 2: remove any interval overlap. For any conflicts, the
# iterval already there wins, and the incoming interval updates
# its bounds accordingly.
if self.__eval_cond(lower < int_expr[n][1]) and \
self.__eval_cond(lower >= int_expr[n][0]):
lower = int_expr[n][1]
elif len(int_expr[n][1].free_symbols) and \
self.__eval_cond(lower >= int_expr[n][0]):
if self.__eval_cond(lower == int_expr[n][0]):
lower = int_expr[n][1]
else:
int_expr[n][1] = Min(lower, int_expr[n][1])
elif len(int_expr[n][1].free_symbols) and \
lower < int_expr[n][0] is not True:
upper = Min(upper, int_expr[n][0])
elif self.__eval_cond(upper > int_expr[n][0]) and \
self.__eval_cond(upper <= int_expr[n][1]):
upper = int_expr[n][0]
elif len(int_expr[n][0].free_symbols) and \
self.__eval_cond(upper < int_expr[n][1]):
int_expr[n][0] = Max(upper, int_expr[n][0])
if self.__eval_cond(
lower >= upper) is not True: # Is it still an interval?
int_expr.append([lower, upper, expr])
if cond is targetcond:
return [(lower, upper)]
elif isinstance(targetcond, Or) and cond in targetcond.args:
or_cond = Or(or_cond, cond)
or_intervals.append((lower, upper))
if or_cond == targetcond:
or_intervals.sort(key=lambda x: x[0])
return or_intervals
int_expr.sort(key=lambda x: x[1].sort_key()
if x[1].is_number else S.NegativeInfinity.sort_key())
int_expr.sort(key=lambda x: x[0].sort_key()
if x[0].is_number else S.Infinity.sort_key())
from sympy.functions.elementary.miscellaneous import MinMaxBase
for n in xrange(len(int_expr)):
if len(int_expr[n][0].free_symbols) or len(
int_expr[n][1].free_symbols):
if isinstance(int_expr[n][1], Min) or int_expr[n][1] == b:
newval = Min(*int_expr[n][:-1])
if n > 0 and int_expr[n][0] == int_expr[n - 1][1]:
int_expr[n - 1][1] = newval
int_expr[n][0] = newval
else:
newval = Max(*int_expr[n][:-1])
if n < len(int_expr) - 1 and int_expr[n][1] == int_expr[
n + 1][0]:
int_expr[n + 1][0] = newval
int_expr[n][1] = newval
# Add holes to list of intervals if there is a default value,
# otherwise raise a ValueError.
holes = []
curr_low = a
for int_a, int_b, expr in int_expr:
if (curr_low < int_a) is True:
holes.append([curr_low, Min(b, int_a), default])
elif (curr_low >= int_a) is not True:
holes.append([curr_low, Min(b, int_a), default])
curr_low = Min(b, int_b)
if (curr_low < b) is True:
holes.append([Min(b, curr_low), b, default])
elif (curr_low >= b) is not True:
holes.append([Min(b, curr_low), b, default])
if holes and default is not None:
int_expr.extend(holes)
if targetcond is True:
return [(h[0], h[1]) for h in holes]
elif holes and default is None:
raise ValueError("Called interval evaluation over piecewise "
"function on undefined intervals %s" %
", ".join([str((h[0], h[1])) for h in holes]))
return int_expr
def sym_transform(self):
return list(map(lambda x: log(Max(RealNumber(self.guard) + RealNumber(self.offset), x + RealNumber(self.offset))), self.syms()))
def _sup(self):
# We use Max so that sup is meaningful in combination with symbolic
# end points.
from sympy.functions.elementary.miscellaneous import Max
return Max(*[set.sup for set in self.args])
def test_Max():
from sympy.abc import x, y, z
n = Symbol('n', negative=True)
n_ = Symbol('n_', negative=True)
nn = Symbol('nn', nonnegative=True)
nn_ = Symbol('nn_', nonnegative=True)
p = Symbol('p', positive=True)
p_ = Symbol('p_', positive=True)
np = Symbol('np', nonpositive=True)
np_ = Symbol('np_', nonpositive=True)
r = Symbol('r', real=True)
assert Max(5, 4) == 5
# lists
raises(ValueError, lambda: Max())
assert Max(x, y) == Max(y, x)
assert Max(x, y, z) == Max(z, y, x)
assert Max(x, Max(y, z)) == Max(z, y, x)
assert Max(x, Min(y, oo)) == Max(x, y)
assert Max(n, -oo, n_, p, 2) == Max(p, 2)
assert Max(n, -oo, n_, p) == p
assert Max(2, x, p, n, -oo, S.NegativeInfinity, n_, p, 2) == Max(2, x, p)
assert Max(0, x, 1, y) == Max(1, x, y)
assert Max(r, r + 1, r - 1) == 1 + r
assert Max(1000, 100, -100, x, p, n) == Max(p, x, 1000)
assert Max(cos(x), sin(x)) == Max(sin(x), cos(x))
assert Max(cos(x), sin(x)).subs(x, 1) == sin(1)
assert Max(cos(x), sin(x)).subs(x, S(1)/2) == cos(S(1)/2)
raises(ValueError, lambda: Max(cos(x), sin(x)).subs(x, I))
raises(ValueError, lambda: Max(I))
raises(ValueError, lambda: Max(I, x))
raises(ValueError, lambda: Max(S.ComplexInfinity, 1))
assert Max(n, -oo, n_, p, 2) == Max(p, 2)
assert Max(n, -oo, n_, p, 1000) == Max(p, 1000)
assert Max(1, x).diff(x) == Heaviside(x - 1)
assert Max(x, 1).diff(x) == Heaviside(x - 1)
assert Max(x**2, 1 + x, 1).diff(x) == \
2*x*Heaviside(x**2 - Max(1, x + 1)) \
+ Heaviside(x - Max(1, x**2) + 1)
e = Max(0, x)
assert e.evalf == e.n
assert e.n().args == (0, x)
# issue 8643
m = Max(p, p_, n, r)
assert m.is_positive is True
assert m.is_nonnegative is True
assert m.is_negative is False
m = Max(n, n_)
assert m.is_positive is False
assert m.is_nonnegative is False
assert m.is_negative is True
m = Max(n, n_, r)
assert m.is_positive is None
assert m.is_nonnegative is None
assert m.is_negative is None
m = Max(n, nn, r)
assert m.is_positive is None
assert m.is_nonnegative is True
assert m.is_negative is False
def _eval_imageset(self, f):
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.solvers import solve
from sympy.core.function import diff
from sympy.series import limit
from sympy.calculus.singularities import singularities
# TODO: handle piecewise defined functions
# TODO: handle functions with infinitely many solutions (eg, sin, tan)
# TODO: handle multivariate functions
expr = f.expr
if len(expr.free_symbols) > 1 or len(f.variables) != 1:
return
var = f.variables[0]
if not self.start.is_comparable or not self.end.is_comparable:
return
try:
sing = [
x for x in singularities(expr, var) if x.is_real and x in self
]
except NotImplementedError:
return
if self.left_open:
_start = limit(expr, var, self.start, dir="+")
elif self.start not in sing:
_start = f(self.start)
if self.right_open:
_end = limit(expr, var, self.end, dir="-")
elif self.end not in sing:
_end = f(self.end)
if len(sing) == 0:
solns = solve(diff(expr, var), var)
extr = [_start, _end
] + [f(x) for x in solns if x.is_real and x in self]
start, end = Min(*extr), Max(*extr)
left_open, right_open = False, False
if _start <= _end:
# the minimum or maximum value can occur simultaneously
# on both the edge of the interval and in some interior
# point
if start == _start and start not in solns:
left_open = self.left_open
if end == _end and end not in solns:
right_open = self.right_open
else:
if start == _end and start not in solns:
left_open = self.right_open
if end == _start and end not in solns:
right_open = self.left_open
return Interval(start, end, left_open, right_open)
else:
return imageset(f, Interval(self.start, sing[0],
self.left_open, True)) + \
Union(*[imageset(f, Interval(sing[i], sing[i + 1]), True, True)
for i in range(1, len(sing) - 1)]) + \
imageset(f, Interval(sing[-1], self.end, True, self.right_open))
def width( self ):
if self.fields:
return Max(*(f.highBit for f in self.fields))
else:
return 0
def test_issue_10395():
eq = x * Max(0, y)
assert nfloat(eq) == eq
eq = x * Max(y, -1.1)
assert nfloat(eq) == eq
assert Max(y, 4).n() == Max(4.0, y)
def test_Min_Max():
# see gh-10375
assert lambdify((x, y, z), Min(x, y, z))(1, 2, 3) == 1
assert lambdify((x, y, z), Max(x, y, z))(1, 2, 3) == 3
def test_issue_21399():
from sympy.abc import a, b, c
assert Max(Min(a, b), Min(a, b, c)) == Min(a, b)
def sum_limit(r, w, n0, di, i0, index=0):
return slice(
di, Max(0, -(i0 // r[index])),
Min(-1 // r[index] + w.shape[index], (n0 - i0 - 1) // r[index]) + 1)
def _print_Max(self, expr):
from sympy.functions.elementary.miscellaneous import Max
if len(expr.args) == 1:
return self._print(expr.args[0])
return "%smax(%s, %s)" % (self._ns, self._print(expr.args[0]),
self._print(Max(*expr.args[1:])))
def test_issue_12638():
from sympy.abc import a, b, c, d
assert Min(a, b, c, Max(a, b)) == Min(a, b, c)
assert Min(a, b, Max(a, b, c)) == Min(a, b)
assert Min(a, b, Max(a, c)) == Min(a, b)
def _intervals(self, sym):
"""Return a list of unique tuples, (a, b, e, i), where a and b
are the lower and upper bounds in which the expression e of
argument i in self is defined and a < b (when involving
numbers) or a <= b when involving symbols.
If there are any relationals not involving sym, or any
relational cannot be solved for sym, NotImplementedError is
raised. The calling routine should have removed such
relationals before calling this routine.
The evaluated conditions will be returned as ranges.
Discontinuous ranges will be returned separately with
identical expressions. The first condition that evaluates to
True will be returned as the last tuple with a, b = -oo, oo.
"""
from sympy.solvers.inequalities import _solve_inequality
from sympy.logic.boolalg import to_cnf, distribute_or_over_and
assert isinstance(self, Piecewise)
def _solve_relational(r):
if sym not in r.free_symbols:
nonsymfail(r)
rv = _solve_inequality(r, sym)
if isinstance(rv, Relational):
free = rv.args[1].free_symbols
if rv.args[0] != sym or sym in free:
raise NotImplementedError(
filldedent('''
Unable to solve relational
%s for %s.''' % (r, sym)))
if rv.rel_op == '==':
# this equality has been affirmed to have the form
# Eq(sym, rhs) where rhs is sym-free; it represents
# a zero-width interval which will be ignored
# whether it is an isolated condition or contained
# within an And or an Or
rv = S.false
elif rv.rel_op == '!=':
try:
rv = Or(sym < rv.rhs, sym > rv.rhs)
except TypeError:
# e.g. x != I ==> all real x satisfy
rv = S.true
elif rv == (S.NegativeInfinity < sym) & (sym < S.Infinity):
rv = S.true
return rv
def nonsymfail(cond):
raise NotImplementedError(
filldedent('''
A condition not involving
%s appeared: %s''' % (sym, cond)))
# make self canonical wrt Relationals
reps = dict([(r, _solve_relational(r))
for r in self.atoms(Relational)])
# process args individually so if any evaluate, their position
# in the original Piecewise will be known
args = [i.xreplace(reps) for i in self.args]
# precondition args
expr_cond = []
default = idefault = None
for i, (expr, cond) in enumerate(args):
if cond is S.false:
continue
elif cond is S.true:
default = expr
idefault = i
break
cond = to_cnf(cond)
if isinstance(cond, And):
cond = distribute_or_over_and(cond)
if isinstance(cond, Or):
expr_cond.extend([(i, expr, o) for o in cond.args
if not isinstance(o, Equality)])
elif cond is not S.false:
expr_cond.append((i, expr, cond))
# determine intervals represented by conditions
int_expr = []
for iarg, expr, cond in expr_cond:
if isinstance(cond, And):
lower = S.NegativeInfinity
upper = S.Infinity
for cond2 in cond.args:
if isinstance(cond2, Equality):
lower = upper # ignore
break
elif cond2.lts == sym:
upper = Min(cond2.gts, upper)
elif cond2.gts == sym:
lower = Max(cond2.lts, lower)
else:
nonsymfail(cond2) # should never get here
elif isinstance(cond, Relational):
lower, upper = cond.lts, cond.gts # part 1: initialize with givens
if cond.lts == sym: # part 1a: expand the side ...
lower = S.NegativeInfinity # e.g. x <= 0 ---> -oo <= 0
elif cond.gts == sym: # part 1a: ... that can be expanded
upper = S.Infinity # e.g. x >= 0 ---> oo >= 0
else:
nonsymfail(cond)
else:
raise NotImplementedError('unrecognized condition: %s' % cond)
lower, upper = lower, Max(lower, upper)
if (lower >= upper) is not S.true:
int_expr.append((lower, upper, expr, iarg))
if default is not None:
int_expr.append(
(S.NegativeInfinity, S.Infinity, default, idefault))
return list(uniq(int_expr))
def test_instantiation_evaluation():
from sympy.abc import v, w, x, y, z
assert Min(1, Max(2, x)) == 1
assert Max(3, Min(2, x)) == 3
assert Min(Max(x, y), Max(x, z)) == Max(x, Min(y, z))
assert set(Min(Max(w, x), Max(y, z)).args) == set([Max(w, x), Max(y, z)])
assert Min(Max(x, y), Max(x, z), w) == Min(w, Max(x, Min(y, z)))
A, B = Min, Max
for i in range(2):
assert A(x, B(x, y)) == x
assert A(x, B(y, A(x, w, z))) == A(x, B(y, A(w, z)))
A, B = B, A
assert Min(w, Max(x, y), Max(v, x, z)) == Min(w, Max(x, Min(y, Max(v, z))))
def test_evalf_bugs():
assert NS(sin(1) + exp(-10**10), 10) == NS(sin(1), 10)
assert NS(exp(10**10) + sin(1), 10) == NS(exp(10**10), 10)
assert NS('expand_log(log(1+1/10**50))', 20) == '1.0000000000000000000e-50'
assert NS('log(10**100,10)', 10) == '100.0000000'
assert NS('log(2)', 10) == '0.6931471806'
assert NS('(sin(x)-x)/x**3', 15, subs={x:
'1/10**50'}) == '-0.166666666666667'
assert NS(sin(1) + Rational(1, 10**100) * I,
15) == '0.841470984807897 + 1.00000000000000e-100*I'
assert x.evalf() == x
assert NS((1 + I)**2 * I, 6) == '-2.00000'
d = {
n: (-1)**Rational(6, 7),
y: (-1)**Rational(4, 7),
x: (-1)**Rational(2, 7)
}
assert NS((x * (1 + y * (1 + n))).subs(d).evalf(),
6) == '0.346011 + 0.433884*I'
assert NS(((-I - sqrt(2) * I)**2).evalf()) == '-5.82842712474619'
assert NS((1 + I)**2 * I, 15) == '-2.00000000000000'
# issue 4758 (1/2):
assert NS(pi.evalf(69) - pi) == '-4.43863937855894e-71'
# issue 4758 (2/2): With the bug present, this still only fails if the
# terms are in the order given here. This is not generally the case,
# because the order depends on the hashes of the terms.
assert NS(20 - 5008329267844 * n**25 - 477638700 * n**37 - 19 * n,
subs={n: .01}) == '19.8100000000000'
assert NS(
((x - 1) * (1 - x)**
1000).n()) == '(1.00000000000000 - x)**1000*(x - 1.00000000000000)'
assert NS((-x).n()) == '-x'
assert NS((-2 * x).n()) == '-2.00000000000000*x'
assert NS((-2 * x * y).n()) == '-2.00000000000000*x*y'
assert cos(x).n(subs={x: 1 + I}) == cos(x).subs(x, 1 + I).n()
# issue 6660. Also NaN != mpmath.nan
# In this order:
# 0*nan, 0/nan, 0*inf, 0/inf
# 0+nan, 0-nan, 0+inf, 0-inf
# >>> n = Some Number
# n*nan, n/nan, n*inf, n/inf
# n+nan, n-nan, n+inf, n-inf
assert (0 * E**(oo)).n() is S.NaN
assert (0 / E**(oo)).n() is S.Zero
assert (0 + E**(oo)).n() is S.Infinity
assert (0 - E**(oo)).n() is S.NegativeInfinity
assert (5 * E**(oo)).n() is S.Infinity
assert (5 / E**(oo)).n() is S.Zero
assert (5 + E**(oo)).n() is S.Infinity
assert (5 - E**(oo)).n() is S.NegativeInfinity
#issue 7416
assert as_mpmath(0.0, 10, {'chop': True}) == 0
#issue 5412
assert ((oo * I).n() == S.Infinity * I)
assert ((oo + oo * I).n() == S.Infinity + S.Infinity * I)
#issue 11518
assert NS(2 * x**2.5, 5) == '2.0000*x**2.5000'
#issue 13076
assert NS(Mul(Max(0, y), x, evaluate=False).evalf()) == 'x*Max(0, y)'
#issue 18516
assert NS(
log(
S(3273390607896141870013189696827599152216642046043064789483291368096133796404674554883270092325904157150886684127560071009217256545885393053328527589376
) /
36360291795869936842385267079543319118023385026001623040346035832580600191583895484198508262979388783308179702534403855752855931517013066142992430916562025780021771247847643450125342836565813209972590371590152578728008385990139795377610001
).evalf(15, chop=True)) == '-oo'
def _sup(self):
from sympy.functions.elementary.miscellaneous import Max
return Max(*self)
def _intervals(self, sym):
"""Return a list of tuples, (a, b, e, i), where a and b
are the lower and upper bounds in which the expression e
of argument i in self is defined.
If there are any relationals not involving sym, or
any relational cannot be solved for sym,
NotImplementedError is raised. The evaluated conditions will
be returned as ranges. Discontinuous ranges will be
returned separately with identical expressions and
the first condition that evaluates to True will be
returned as the last tuple with a, b = -oo, oo.
"""
from sympy.solvers.inequalities import _solve_inequality
from sympy.logic.boolalg import to_cnf, distribute_or_over_and
assert isinstance(self, Piecewise)
def _solve_relational(r):
rv = _solve_inequality(r, sym)
if isinstance(rv, Relational) and \
sym in rv.free_symbols:
if rv.args[0] != sym:
raise NotImplementedError(
filldedent('''
Unable to solve relational
%s for %s.''' % (r, sym)))
if rv.rel_op == '!=':
try:
rv = Or(sym < rv.rhs, sym > rv.rhs)
except TypeError:
# e.g. x != I ==> all real x satisfy
rv = S.true
if rv == (S.NegativeInfinity < sym) & (sym < S.Infinity):
rv = S.true
return rv
def nonsymfail(cond):
raise NotImplementedError(
filldedent('''
A condition not involving
%s appeared: %s''' % (sym, cond)))
# make self canonical wrt Relationals
reps = dict([(r, _solve_relational(r))
for r in self.atoms(Relational)])
# process args individually so if any evaluate, their position
# in the original Piecewise will be known
args = [i.xreplace(reps) for i in self.args]
# precondition args
expr_cond = []
default = idefault = None
for i, (expr, cond) in enumerate(args):
if cond == False:
continue
elif cond == True:
default = expr
idefault = i
break
elif sym not in cond.free_symbols:
nonsymfail(cond)
cond = to_cnf(cond)
if isinstance(cond, And):
cond = distribute_or_over_and(cond)
if isinstance(cond, Or):
expr_cond.extend([(i, expr, o) for o in cond.args])
elif cond != False:
expr_cond.append((i, expr, cond))
# determine intervals represented by conditions
int_expr = []
for iarg, expr, cond in expr_cond:
if isinstance(cond, Equality):
if cond.lhs == sym:
v = cond.rhs
int_expr.append((v, v, expr.subs(sym, v), iarg))
continue
else:
nonsymfail(cond)
if isinstance(cond, And):
lower = S.NegativeInfinity
upper = S.Infinity
nonsym = False
rhs = None
for cond2 in cond.args:
if isinstance(cond2, Equality):
# all relationals were solved and
# only sym-dependent ones made it to here
assert cond2.lhs == sym
assert sym not in cond2.rhs.free_symbols
if rhs is None:
rhs = cond2.rhs
else:
same = Eq(cond2.rhs, rhs)
if same == False:
cond = S.false
break
elif same != True:
raise Undecidable('%s did not evaluate' % same)
elif cond2.lts == sym:
upper = Min(cond2.gts, upper)
elif cond2.gts == sym:
lower = Max(cond2.lts, lower)
else:
# mark but don't fail until later
nonsym = cond2
if rhs is not None and cond not in (S.true, S.false):
lower = upper = rhs
cond = cond.subs(sym, lower)
# cond might have evaluated b/c of an Eq
if cond is S.true:
default = expr
continue
elif cond is S.false:
continue
elif nonsym is not False:
nonsymfail(nonsym)
else:
pass # for coverage
elif isinstance(cond, Relational):
lower, upper = cond.lts, cond.gts # part 1: initialize with givens
if cond.lts == sym: # part 1a: expand the side ...
lower = S.NegativeInfinity # e.g. x <= 0 ---> -oo <= 0
elif cond.gts == sym: # part 1a: ... that can be expanded
upper = S.Infinity # e.g. x >= 0 ---> oo >= 0
else:
nonsymfail(cond)
else:
raise NotImplementedError('unrecognized condition: %s' % cond)
lower, upper = lower, Max(lower, upper)
if (lower > upper) is not S.true:
int_expr.append((lower, upper, expr, iarg))
if default is not None:
int_expr.append(
(S.NegativeInfinity, S.Infinity, default, idefault))
return int_expr
def __pow__(self, other):
from sympy.functions.elementary.miscellaneous import real_root
if isinstance(other, Expr):
if other is S.Infinity:
if self.min.is_nonnegative:
if self.max < 1:
return S.Zero
if self.min > 1:
return S.Infinity
return AccumBounds(0, oo)
elif self.max.is_negative:
if self.min > -1:
return S.Zero
if self.max < -1:
return FiniteSet(-oo, oo)
return AccumBounds(-oo, oo)
else:
if self.min > -1:
if self.max < 1:
return S.Zero
return AccumBounds(0, oo)
return AccumBounds(-oo, oo)
if other is S.NegativeInfinity:
return (1/self)**oo
if other.is_real and other.is_number:
if other.is_zero:
return S.One
if other.is_Integer:
if self.min.is_positive:
return AccumBounds(Min(self.min**other, self.max**other),
Max(self.min**other, self.max**other))
elif self.max.is_negative:
return AccumBounds(Min(self.max**other, self.min**other),
Max(self.max**other, self.min**other))
if other % 2 == 0:
if other.is_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(self.min**other, oo)
return AccumBounds(0, oo)
return AccumBounds(S.Zero,
Max(self.min**other, self.max**other))
else:
if other.is_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(-oo, self.min**other)
return AccumBounds(-oo, oo)
return AccumBounds(self.min**other, self.max**other)
num, den = other.as_numer_denom()
if num == S(1):
if den % 2 == 0:
if S.Zero in self:
if self.min.is_negative:
return AccumBounds(0, real_root(self.max, den))
return AccumBounds(real_root(self.min, den),
real_root(self.max, den))
num_pow = self**num
return num_pow**(1/den)
return Pow(self, other, evaluate=False)
return NotImplemented
def __pow__(self, other):
if isinstance(other, Expr):
if other is S.Infinity:
if self.min.is_extended_nonnegative:
if self.max < 1:
return S.Zero
if self.min > 1:
return S.Infinity
return AccumBounds(0, oo)
elif self.max.is_extended_negative:
if self.min > -1:
return S.Zero
if self.max < -1:
return zoo
return S.NaN
else:
if self.min > -1:
if self.max < 1:
return S.Zero
return AccumBounds(0, oo)
return AccumBounds(-oo, oo)
if other is S.NegativeInfinity:
return (1 / self)**oo
# generically true
if (self.max - self.min).is_nonnegative:
# well defined
if self.min.is_nonnegative:
# no 0 to worry about
if other.is_nonnegative:
# no infinity to worry about
return self.func(self.min**other, self.max**other)
if other.is_zero:
return S.One # x**0 = 1
if other.is_Integer or other.is_integer:
if self.min.is_extended_positive:
return AccumBounds(Min(self.min**other, self.max**other),
Max(self.min**other, self.max**other))
elif self.max.is_extended_negative:
return AccumBounds(Min(self.max**other, self.min**other),
Max(self.max**other, self.min**other))
if other % 2 == 0:
if other.is_extended_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(self.min**other, oo)
return AccumBounds(0, oo)
return AccumBounds(S.Zero,
Max(self.min**other, self.max**other))
elif other % 2 == 1:
if other.is_extended_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(-oo, self.min**other)
return AccumBounds(-oo, oo)
return AccumBounds(self.min**other, self.max**other)
# non-integer exponent
# 0**neg or neg**frac yields complex
if (other.is_number or other.is_rational) and (
self.min.is_extended_nonnegative or
(other.is_extended_nonnegative
and self.min.is_extended_nonnegative)):
num, den = other.as_numer_denom()
if num is S.One:
return AccumBounds(*[i**(1 / den) for i in self.args])
elif den is not S.One: # e.g. if other is not Float
return (self**num)**(1 / den) # ok for non-negative base
if isinstance(other, AccumBounds):
if (self.min.is_extended_positive
or self.min.is_extended_nonnegative
and other.min.is_extended_nonnegative):
p = [self**i for i in other.args]
if not any(i.is_Pow for i in p):
a = [j for i in p for j in i.args or (i, )]
try:
return self.func(min(a), max(a))
except TypeError: # can't sort
pass
return Pow(self, other, evaluate=False)
return NotImplemented
def limit_seq(expr, n=None, trials=5):
"""Finds the limit of a sequence as index ``n`` tends to infinity.
Parameters
==========
expr : Expr
SymPy expression for the ``n-th`` term of the sequence
n : Symbol, optional
The index of the sequence, an integer that tends to positive
infinity. If None, inferred from the expression unless it has
multiple symbols.
trials: int, optional
The algorithm is highly recursive. ``trials`` is a safeguard from
infinite recursion in case the limit is not easily computed by the
algorithm. Try increasing ``trials`` if the algorithm returns ``None``.
Admissible Terms
================
The algorithm is designed for sequences built from rational functions,
indefinite sums, and indefinite products over an indeterminate n. Terms of
alternating sign are also allowed, but more complex oscillatory behavior is
not supported.
Examples
========
>>> from sympy import limit_seq, Sum, binomial
>>> from sympy.abc import n, k, m
>>> limit_seq((5*n**3 + 3*n**2 + 4) / (3*n**3 + 4*n - 5), n)
5/3
>>> limit_seq(binomial(2*n, n) / Sum(binomial(2*k, k), (k, 1, n)), n)
3/4
>>> limit_seq(Sum(k**2 * Sum(2**m/m, (m, 1, k)), (k, 1, n)) / (2**n*n), n)
4
See Also
========
sympy.series.limitseq.dominant
References
==========
.. [1] Computing Limits of Sequences - Manuel Kauers
"""
from sympy.concrete.summations import Sum
if n is None:
free = expr.free_symbols
if len(free) == 1:
n = free.pop()
elif not free:
return expr
else:
raise ValueError("Expression has more than one variable. "
"Please specify a variable.")
elif n not in expr.free_symbols:
return expr
expr = expr.rewrite(fibonacci, S.GoldenRatio)
expr = expr.rewrite(factorial, subfactorial, gamma)
n_ = Dummy("n", integer=True, positive=True)
n1 = Dummy("n", odd=True, positive=True)
n2 = Dummy("n", even=True, positive=True)
# If there is a negative term raised to a power involving n, or a
# trigonometric function, then consider even and odd n separately.
powers = (p.as_base_exp() for p in expr.atoms(Pow))
if (any(b.is_negative and e.has(n) for b, e in powers)
or expr.has(cos, sin)):
L1 = _limit_seq(expr.xreplace({n: n1}), n1, trials)
if L1 is not None:
L2 = _limit_seq(expr.xreplace({n: n2}), n2, trials)
if L1 != L2:
if L1.is_comparable and L2.is_comparable:
return AccumulationBounds(Min(L1, L2), Max(L1, L2))
else:
return None
else:
L1 = _limit_seq(expr.xreplace({n: n_}), n_, trials)
if L1 is not None:
return L1
else:
if expr.is_Add:
limits = [limit_seq(term, n, trials) for term in expr.args]
if any(result is None for result in limits):
return None
else:
return Add(*limits)
# Maybe the absolute value is easier to deal with (though not if
# it has a Sum). If it tends to 0, the limit is 0.
elif not expr.has(Sum):
lim = _limit_seq(Abs(expr.xreplace({n: n_})), n_, trials)
if lim is not None and lim.is_zero:
return S.Zero
def _set_function(f, x): # noqa:F811
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.solvers.solveset import solveset
from sympy.core.function import diff, Lambda
from sympy.series import limit
from sympy.calculus.singularities import singularities
from sympy.sets import Complement
# TODO: handle functions with infinitely many solutions (eg, sin, tan)
# TODO: handle multivariate functions
expr = f.expr
if len(expr.free_symbols) > 1 or len(f.variables) != 1:
return
var = f.variables[0]
if not var.is_real:
if expr.subs(var, Dummy(real=True)).is_real is False:
return
if expr.is_Piecewise:
result = S.EmptySet
domain_set = x
for (p_expr, p_cond) in expr.args:
if p_cond is true:
intrvl = domain_set
else:
intrvl = p_cond.as_set()
intrvl = Intersection(domain_set, intrvl)
if p_expr.is_Number:
image = FiniteSet(p_expr)
else:
image = imageset(Lambda(var, p_expr), intrvl)
result = Union(result, image)
# remove the part which has been `imaged`
domain_set = Complement(domain_set, intrvl)
if domain_set is S.EmptySet:
break
return result
if not x.start.is_comparable or not x.end.is_comparable:
return
try:
sing = [i for i in singularities(expr, var) if i.is_real and i in x]
except NotImplementedError:
return
if x.left_open:
_start = limit(expr, var, x.start, dir="+")
elif x.start not in sing:
_start = f(x.start)
if x.right_open:
_end = limit(expr, var, x.end, dir="-")
elif x.end not in sing:
_end = f(x.end)
if len(sing) == 0:
solns = list(solveset(diff(expr, var), var))
extr = [_start, _end] + [f(i) for i in solns if i.is_real and i in x]
start, end = Min(*extr), Max(*extr)
left_open, right_open = False, False
if _start <= _end:
# the minimum or maximum value can occur simultaneously
# on both the edge of the interval and in some interior
# point
if start == _start and start not in solns:
left_open = x.left_open
if end == _end and end not in solns:
right_open = x.right_open
else:
if start == _end and start not in solns:
left_open = x.right_open
if end == _start and end not in solns:
right_open = x.left_open
return Interval(start, end, left_open, right_open)
else:
return imageset(f, Interval(x.start, sing[0],
x.left_open, True)) + \
Union(*[imageset(f, Interval(sing[i], sing[i + 1], True, True))
for i in range(0, len(sing) - 1)]) + \
imageset(f, Interval(sing[-1], x.end, True, x.right_open))
def _rsolve_hypergeometric(f, x, P, Q, k, m):
"""Recursive wrapper to rsolve_hypergeometric.
Returns a Tuple of (formula, series independent terms,
maximum power of x in independent terms) if successful
otherwise ``None``.
See :func:`rsolve_hypergeometric` for details.
"""
from sympy.polys import lcm, roots
from sympy.integrals import integrate
# transformation - c
proots, qroots = roots(P, k), roots(Q, k)
all_roots = dict(proots)
all_roots.update(qroots)
scale = lcm(
[r.as_numer_denom()[1] for r, t in all_roots.items() if r.is_rational])
f, P, Q, m = _transformation_c(f, x, P, Q, k, m, scale)
# transformation - a
qroots = roots(Q, k)
if qroots:
k_min = Min(*qroots.keys())
else:
k_min = S.Zero
shift = k_min + m
f, P, Q, m = _transformation_a(f, x, P, Q, k, m, shift)
l = (x * f).limit(x, 0)
if not isinstance(l, Limit) and l != 0: # Ideally should only be l != 0
return None
qroots = roots(Q, k)
if qroots:
k_max = Max(*qroots.keys())
else:
k_max = S.Zero
ind, mp = S.Zero, -oo
for i in range(k_max + m + 1):
r = f.diff(x, i).limit(x, 0) / factorial(i)
if r.is_finite is False:
old_f = f
f, P, Q, m = _transformation_a(f, x, P, Q, k, m, i)
f, P, Q, m = _transformation_e(f, x, P, Q, k, m)
sol, ind, mp = _rsolve_hypergeometric(f, x, P, Q, k, m)
sol = _apply_integrate(sol, x, k)
sol = _apply_shift(sol, i)
ind = integrate(ind, x)
ind += (old_f - ind).limit(x, 0) # constant of integration
mp += 1
return sol, ind, mp
elif r:
ind += r * x**(i + shift)
pow_x = Rational((i + shift), scale)
if pow_x > mp:
mp = pow_x # maximum power of x
ind = ind.subs(x, x**(1 / scale))
sol = _compute_formula(f, x, P, Q, k, m, k_max)
sol = _apply_shift(sol, shift)
sol = _apply_scale(sol, scale)
return sol, ind, mp
def _eval_interval(self, sym, a, b):
"""Evaluates the function along the sym in a given interval ab"""
# FIXME: Currently complex intervals are not supported. A possible
# replacement algorithm, discussed in issue 2128, can be found in the
# following papers;
# http://portal.acm.org/citation.cfm?id=281649
# http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.70.4127&rep=rep1&type=pdf
if a is None or b is None:
# In this case, it is just simple substitution
return super(Piecewise, self)._eval_interval(sym, a, b)
mul = 1
if (a == b) is True:
return S.Zero
elif (a > b) is True:
a, b, mul = b, a, -1
elif (a <= b) is not True:
newargs = []
for e, c in self.args:
intervals = self._sort_expr_cond(sym, S.NegativeInfinity,
S.Infinity, c)
values = []
for lower, upper in intervals:
if (a < lower) is True:
mid = lower
rep = b
val = e.subs(sym, b) - e.subs(sym, mid)
val += self._eval_interval(sym, a, mid)
elif (a > upper) is True:
mid = upper
rep = b
val = e.subs(sym, b) - e.subs(sym, mid)
val += self._eval_interval(sym, a, mid)
elif (a >= lower) is True and (a <= upper) is True:
rep = b
val = e.subs(sym, b) - e.subs(sym, a)
elif (b < lower) is True:
mid = lower
rep = a
val = e.subs(sym, mid) - e.subs(sym, a)
val += self._eval_interval(sym, mid, b)
elif (b > upper) is True:
mid = upper
rep = a
val = e.subs(sym, mid) - e.subs(sym, a)
val += self._eval_interval(sym, mid, b)
elif ((b >= lower) is True) and ((b <= upper) is True):
rep = a
val = e.subs(sym, b) - e.subs(sym, a)
else:
raise NotImplementedError(
"""The evaluation of a Piecewise interval when both the lower
and the upper limit are symbolic is not yet implemented."""
)
values.append(val)
if len(set(values)) == 1:
try:
c = c.subs(sym, rep)
except AttributeError:
pass
e = values[0]
newargs.append((e, c))
else:
for i in range(len(values)):
newargs.append(
(values[i], (c is True and i == len(values) - 1)
or And(rep >= intervals[i][0],
rep <= intervals[i][1])))
return Piecewise(*newargs)
# Determine what intervals the expr,cond pairs affect.
int_expr = self._sort_expr_cond(sym, a, b)
# Finally run through the intervals and sum the evaluation.
ret_fun = 0
for int_a, int_b, expr in int_expr:
ret_fun += expr._eval_interval(sym, Max(a, int_a), Min(b, int_b))
return mul * ret_fun
