本文整理汇总了Python中sympy.holonomic.HolonomicFunction.evalf方法的典型用法代码示例。如果您正苦于以下问题：Python HolonomicFunction.evalf方法的具体用法？Python HolonomicFunction.evalf怎么用？Python HolonomicFunction.evalf使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类sympy.holonomic.HolonomicFunction的用法示例。
在下文中一共展示了HolonomicFunction.evalf方法的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: test_evalf_rk4
# 需要导入模块: from sympy.holonomic import HolonomicFunction [as 别名]
# 或者: from sympy.holonomic.HolonomicFunction import evalf [as 别名]
def test_evalf_rk4():
x = symbols('x')
R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
# log(1+x)
p = HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1])
# path taken is a straight line from 0 to 1, on the real axis
r = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1]
s = '0.693146363174626' # approx. equal to log(2) i.e. 0.693147180559945
assert sstr(p.evalf(r)[-1]) == s
# path taken is a traingle 0-->1+i-->2
r = [0.1 + 0.1*I]
for i in range(9):
r.append(r[-1]+0.1+0.1*I)
for i in range(10):
r.append(r[-1]+0.1-0.1*I)
# close to the exact solution 1.09861228866811
# imaginary part also close to zero
s = '1.09861574485151 + 1.36082967699958e-7*I'
assert sstr(p.evalf(r)[-1]) == s
# sin(x)
p = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1])
s = '0.90929463522785 + 1.52655665885959e-16*I'
assert sstr(p.evalf(r)[-1]) == s
# computing sin(pi/2) using this method
# using a linear path from 0 to pi/2
r = [0.1]
for i in range(14):
r.append(r[-1] + 0.1)
r.append(pi/2)
s = '0.999999895088917' # close to 1.0 (exact solution)
assert sstr(p.evalf(r)[-1]) == s
# trying different path, a rectangle (0-->i-->pi/2 + i-->pi/2)
# computing the same value sin(pi/2) using different path
r = [0.1*I]
for i in range(9):
r.append(r[-1]+0.1*I)
for i in range(15):
r.append(r[-1]+0.1)
r.append(pi/2+I)
for i in range(10):
r.append(r[-1]-0.1*I)
# close to 1.0
s = '1.00000003415141 + 6.11940487991086e-16*I'
assert sstr(p.evalf(r)[-1]) == s
# cos(x)
p = HolonomicFunction(Dx**2 + 1, x, 0, [1, 0])
# compute cos(pi) along 0-->pi
r = [0.05]
for i in range(61):
r.append(r[-1]+0.05)
r.append(pi)
# close to -1 (exact answer)
s = '-0.999999993238714'
assert sstr(p.evalf(r)[-1]) == s
# a rectangular path (0 -> i -> 2+i -> 2)
r = [0.1*I]
for i in range(9):
r.append(r[-1]+0.1*I)
for i in range(20):
r.append(r[-1]+0.1)
for i in range(10):
r.append(r[-1]-0.1*I)
p = HolonomicFunction(Dx**2 + 1, x, 0, [1,1]).evalf(r)
s = '0.493152791638442 - 1.41553435639707e-15*I'
assert sstr(p[-1]) == s示例2: test_evalf_euler
# 需要导入模块: from sympy.holonomic import HolonomicFunction [as 别名]
# 或者: from sympy.holonomic.HolonomicFunction import evalf [as 别名]
def test_evalf_euler():
x = symbols('x')
R, Dx = DifferentialOperators(QQ.old_poly_ring(x), 'Dx')
# log(1+x)
p = HolonomicFunction((1 + x)*Dx**2 + Dx, x, 0, [0, 1])
# path taken is a straight line from 0 to 1, on the real axis
r = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1]
s = '0.699525841805253' # approx. equal to log(2) i.e. 0.693147180559945
assert sstr(p.evalf(r, method='Euler')[-1]) == s
# path taken is a traingle 0-->1+i-->2
r = [0.1 + 0.1*I]
for i in range(9):
r.append(r[-1]+0.1+0.1*I)
for i in range(10):
r.append(r[-1]+0.1-0.1*I)
# close to the exact solution 1.09861228866811
# imaginary part also close to zero
s = '1.07530466271334 - 0.0251200594793912*I'
assert sstr(p.evalf(r, method='Euler')[-1]) == s
# sin(x)
p = HolonomicFunction(Dx**2 + 1, x, 0, [0, 1])
s = '0.905546532085401 - 6.93889390390723e-18*I'
assert sstr(p.evalf(r, method='Euler')[-1]) == s
# computing sin(pi/2) using this method
# using a linear path from 0 to pi/2
r = [0.1]
for i in range(14):
r.append(r[-1] + 0.1)
r.append(pi/2)
s = '1.08016557252834' # close to 1.0 (exact solution)
assert sstr(p.evalf(r, method='Euler')[-1]) == s
# trying different path, a rectangle (0-->i-->pi/2 + i-->pi/2)
# computing the same value sin(pi/2) using different path
r = [0.1*I]
for i in range(9):
r.append(r[-1]+0.1*I)
for i in range(15):
r.append(r[-1]+0.1)
r.append(pi/2+I)
for i in range(10):
r.append(r[-1]-0.1*I)
# close to 1.0
s = '0.976882381836257 - 1.65557671738537e-16*I'
assert sstr(p.evalf(r, method='Euler')[-1]) == s
# cos(x)
p = HolonomicFunction(Dx**2 + 1, x, 0, [1, 0])
# compute cos(pi) along 0-->pi
r = [0.05]
for i in range(61):
r.append(r[-1]+0.05)
r.append(pi)
# close to -1 (exact answer)
s = '-1.08140824719196'
assert sstr(p.evalf(r, method='Euler')[-1]) == s
# a rectangular path (0 -> i -> 2+i -> 2)
r = [0.1*I]
for i in range(9):
r.append(r[-1]+0.1*I)
for i in range(20):
r.append(r[-1]+0.1)
for i in range(10):
r.append(r[-1]-0.1*I)
p = HolonomicFunction(Dx**2 + 1, x, 0, [1,1]).evalf(r, method='Euler')
s = '0.501421652861245 - 3.88578058618805e-16*I'
assert sstr(p[-1]) == s